Update: AC died -- HVAC problems - low refrigerant on the ac, what to do

[Sibley]

I have an old 80% furnace and a/c. 20+ years old. Had the hvac company out today for annual maintenance on the a/c and it's low on refrigerant. The guy said its between 1 and 3 pounds low. It is unusually cool here, it was in the 50s this morning while he was here. I've never had to add refrigerant, and have not been told it's low in the past. It uses R22. The wrench in the mix here is I have been planning to replace the furnace and AC in 2024. I do not run the ac 24/7, but only when I'm uncomfortable, and I run cold. I will also run it for the 4th of July to help with fireworks noise. That sort of thing.

I could add refrigerant. This obviously costs money, and right now the max cost I know of is $600 (assuming needs 3 lbs). I can call other places for quotes, but realistically R22 is being phased out so its going to cost more.
I could leave it alone. It might freeze up, which could cause bigger problems and turn into an emergency.
I could move up my time frame for replacement and replace this year.

Bigger picture, I was planning on replacing both units in 2024. They're old, I know this. I had thought to research heat pumps and see if they were going to work for my house and climate. If not, then figuring out what kind of adjustments would be needed for a more efficient furnace and ac.

I live in Indiana. My temps range from hot and humid (100F is possible, more is possible but extreme) down to bitter cold (lowest temp since I bought the house was -20F). "Normal" is 80s/low 90s in the summer, 20s/30s in the winter.

----Ramblings.
I would prefer not to add refrigerant to the existing system. Maybe because it's June and I'm wearing a fleece and still cold, but I'm not loving the idea of spending a ton of money on fixing something that I'm going to replace in a year.

I don't know enough about HVAC to judge the risks here. I  know that the ac could freeze up, I know that if it does and then melts all over the furnace then that could damage the furnace. I don't know how likely any of this is.

Heat pumps. I like the idea of them. I'm not convinced it'll work for my house. My house is old. I have good attic insulation, but no wall insulation and I can't do blown in. Air sealing is decent, but it's an old house. A less efficient house means I need my heating in the winter to be able to keep up. I have no concerns with a heat pump down to the 30s and I'm pretty sure it'll work down to 0. But I have to plan for -20. A heating system that fails when you most need it is not acceptable. So that means that a heat pump plus backup might work, because I wouldn't be relying entirely on a heat pump when it gets cold. However, I don't know what "backup" means in this case - electric heat? Expensive and inefficient. Gas furnace? Seems overkill, plus expensive. I also have longevity questions on a heat pump, and practical access to technicians. I'm not sure I could get service or repair in a timely manner, the hvac companies in my area haven't embraced heat pumps yet. And what about parts? Are they widely and consistently available? Plus, operating in more extreme conditions is going to be rougher on equipment, so I would expect that my average 20s/30s winters would cause more wear and tear than somewhere a bit warmer.

There's also supply to be concerned with. I know there were backlogs due to supply chain issues, and while I'm sure it's improved there's also the new(er) tax credits out which won't help. Can I realistically move forward with replacement in the next few weeks? I don't know My original plan was to do the replacement as a routine item so I could schedule and if there were supply issues it would be fine. I don't know how the market is right now.

Financing: I just spent a massive portion of my "defined available" savings on a big family trip, there isn't enough left to cover new hvac. There's plenty of money in my emergency fund or other savings, or I could get financing. So money is fine, I'm just cheap.

Obviously, I'm not sure what to do. While I'm watching HVAC youtube videos because I just need more general knowledge, I would appreciate hearing from everyone here.

[Sibley]

If I do replace and stick with gas, then I'd like to get a more efficient furnace. Right now, the furnace vents up the chimney and I don't remember if it has a liner. The water heater also vents up the chimney. So I'd have to consider the venting situation. Beyond that, I don't know what I don't know.

The current furnace is updraft, but it was possibly originally downdraft and then converted. The whole configuration needs to be looked at and made sure it's as good as possible. They kinda jury rigged ducts in when they converted to the furnace.

[GilesMM]

I would purchase nothing until something actually breaks.  Sounds like the technician was trying to scare you into a new unit. 


But when the time comes, you want to be ready with a plan.  So, find out who is doing heat pump conversions in your area and get them out for an estimate and a discussion of your concerns.  Ask for references.  Then, when the AC or furnace finally dies, you know what equipment you want.  You can re-bid it then.


Keep in mind furnaces run almost forever.  You can probably keep yours as backup and just get the heat pump when the AC dies.  If the AC has a serious leak, then it probably can't be repaired.

[Sibley]

I've been using this company for a few years, but this is a new tech. If it was the same tech, then I have history and would trust his recommendation. This guy I just don't know. So yeah, grain of salt.

I like the idea of estimates and discussions with heat pump.

[Telecaster]

The IRA currently has an $8000 tax credit for heat pump installation (actually varies based on local income).   I'm of the view it is better to fix than replace, but that is a pretty good sweetener and 20 years is about the useful life of HVAC equipment anyway, so maybe it is time to pull the pin. 

Just throwing spaghetti...could you install the heat pump and keep the furnace as backup?   

[Sibley]

Well, here is what I've accomplished.

-Requested a couple estimates for heat pumps.
-Contacted and scheduled another hvac tech to look at the existing ac unit and give me an estimate to add refrigerant. Edit: yes, this costs money, but this guy was recommended by a friend of mine who is in the trades, and I'll be more comfortable with a 2nd opinion. plus, it won't be 55 degrees when this guy will be here.
-My neighbor sent me a youtube channel on hvac that he likes, will check that out. I need to learn.
-accepted that I am cold and as a result, grumpy. Making hot tea.

[Sibley]

Well, I have watched a lot of youtube videos. And read a lot of HVAC websites. I now know a lot about how ac's work and more about furnaces than I did. Here is my conclusion: try to fix the leak. And don't replace them next year if I can avoid it. Realistically, it's far more cost effective over the long term to keep these units running, even with the lower efficiency. The less efficient units are much simpler, so less chance of failure and when something does break, it tends to be cheaper to fix.

So, we'll see what the tech on Monday says. I will still get the heat pump estimates, in large part because gathering all the information is a very good idea. But they're pushing heat pumps so much that the longer I can hold off, the better they'll be (or something better is invented).

[uniwelder]

A couple of questions for you----

1) What other appliances use natural gas?  It sounds like your water heater does.  How about your stove?  I wonder if you wanted to make the switch to heat pump, would you still use natural gas in your home or would you convert everything over to electric?

2) Have you looked at wall mounted mini-splits?  If your home is open enough, you could just install one now, while your central hvac system is still functioning.  That would let you dip your toe in the water regarding heat pumps.  This assumes your house has an open floor plan, or at least one large enough area for the wall mount unit to cover a decent square footage.  If you like it, it might be possible to install a second one that will cover the remainder of the house.

[Sibley]

1. Gas right now is stove, water heater, and furnace. I do not like gas stoves but am not planning on switching until I redo the kitchen. Which is not on the short or medium term plan list right now. Water heater I'm perfectly willing to switch, but it's silly to replace a 6 year old water heater that's working just fine.

2. I have not. Downstairs is semi open, upstairs is not. Air flow would be the issue not square footage probably. In my mind, minisplits are awesome for those who don't have ductwork, their ductwork is no longer functional, they can't get natural gas to the house (ie, stuck with oil otherwise), or an option for new builds. I'm not in that situation.

RE heat pumps, I looked for contractors in my area. I found 3, all big ones. Which tells me that it's early adopters right now. This is good, because early adopters will either prove out the tech or highlight the problems so they can improve it, which will then prove out the tech. But I really don't want to be an early adopter. I also don't want to lock into a new gas furnace. Ideally, I can keep these units running for a few more years until heat pumps move out of the early adopter stage. The proxy for telling me this, I think, is how many of these HVAC companies install/service heat pumps. There are strong incentives with the tax credits to put in heat pumps, and this is going to speed up the process. It's just too early for my comfort level.

If it would be doable, I'd be comfortable with a heat pump plus my existing furnace for the really cold times. I just don't know if that would be doable. I know that there's some weird stuff with the setup, and it's not really a good idea to extensively mess with 20 year old equipment if you can avoid it. I will get estimates on a heat pump and discuss this with them.

Yes, I'm aware that I'm talking in circles.

[uniwelder]

Here's something I was thinking about from other hvac posts--- coldest design temp for hvac.  You've insisted in the past about wanting an hvac system that can keep your house toasty warm in the coldest temperatures--- negative 20 degrees, which is nearly the record low ever recorded for Chicago.  The actual temp that hvac systems are properly designed for in what seems to be your area is -3 F.  That should really be your target.

[FINate]

We went through a similar process replacing our HVAC last year. Did the recharge of the old AC once spring 2021 to extend usage for one additional summer season, then waited to see what happened after that. Worked fine that summer, but was low on refrigerant spring 2022, not terribly surprising. Didn't want to keep dumping refrigerant (esp. the old stuff) into the atmosphere, so we decided to replace the HVAC. The furnace was also quite old and drawing a lot of amps, well past it's life expectancy, so we replace the entire system. We also looked into heat pumps and came to same conclusion: it's mostly early adopters. A few of our neighbors have newer heat pumps so I asked around about their experience and heard very mixed results. They work great for some whereas others have struggled to keep their house warm in cold temps. Researching more, I came to the conclusion that heat pump tech exists that works in cold climates, but only if the correct system is correctly installed in a house that can handle it. And the big HVAC companies in my city don't yet have technicians trained to spec and install heat pumps. So we replace the HVAC with another 80% furnace and a 13 SEER AC unit, which is much more efficient than the 20 year old unit it replaced, but much simpler and easier to repair than a higher efficiency unit (don't really run the AC for much of the year anyway).

[Sibley]

Here's something I was thinking about from other hvac posts--- coldest design temp for hvac.  You've insisted in the past about wanting an hvac system that can keep your house toasty warm in the coldest temperatures--- negative 20 degrees, which is nearly the record low ever recorded for Chicago.  The actual temp that hvac systems are properly designed for in what seems to be your area is -3 F.  That should really be your target.

Not toasty warm. Warm enough that the pipes don't freeze, which works out to be about 60 in the main house. The utility room will freeze because it always freezes below zero and that's why I have shutoffs so I can isolate those pipes. The existing system managed to keep the house between 60-65, and I have attic insulation now which will help.

[Sibley]

We went through a similar process replacing our HVAC last year. Did the recharge of the old AC once spring 2021 to extend usage for one additional summer season, then waited to see what happened after that. Worked fine that summer, but was low on refrigerant spring 2022, not terribly surprising. Didn't want to keep dumping refrigerant (esp. the old stuff) into the atmosphere, so we decided to replace the HVAC. The furnace was also quite old and drawing a lot of amps, well past it's life expectancy, so we replace the entire system. We also looked into heat pumps and came to same conclusion: it's mostly early adopters. A few of our neighbors have newer heat pumps so I asked around about their experience and heard very mixed results. They work great for some whereas others have struggled to keep their house warm in cold temps. Researching more, I came to the conclusion that heat pump tech exists that works in cold climates, but only if the correct system is correctly installed in a house that can handle it. And the big HVAC companies in my city don't yet have technicians trained to spec and install heat pumps. So we replace the HVAC with another 80% furnace and a 13 SEER AC unit, which is much more efficient than the 20 year old unit it replaced, but much simpler and easier to repair than a higher efficiency unit (don't really run the AC for much of the year anyway).

Yeah, I'm starting to think that's the direction I'll have to go in. The biggest bang for improvement in my house really will be air sealing and insulation, not furnace efficiency. And I've done the cheap stuff in that category. Next easiest would be the crawl space, which technically should wait until after I solve a water problem outside (which will be very expensive to solve).

I really am skeptical about whether a heat pump can handle my house yet. All the people I've talked to online who have heat pumps and say they work fine have modern houses. There's a huge difference between my 1918 house and their 1980 house. They are simply not comparable in many ways. And I haven't found people with the old house and a well functioning heat pump.

[ChpBstrd]

I replaced my heat pump in 2022 (house built in 1940, uninsulated walls). My whole-house electrical expenses for the 12 months prior to replacing the HP were almost double what they were for the 12 months after replacing the HP. In other words, there is a high cost to running an AC or a HP that has low refrigerant or that is worn out.

While my system was being replaced, I put an old 5k BTU air conditioner in the dining room window. It ran 24/7 and kept the whole 1300sf house 15-20F cooler than the peak outside temperature. It also actually did a better job dehumidifying the house than the central AC.

Based on my experience, this is what I'm going to recommend:

1) DO NOT invest any money into a 20+ year old HVAC system with super-expensive R22. That is money down the drain. I do expect the gas furnace to work through the winter though, so this buys you some time if you can just get through this summer:

2) DO replace the system in 2024 as planned. There's no need to fear heat pumps. Just confirm with your technician that the HP being installed is designed for your climate and is appropriately sized for your house. Likewise, if you like the feeling of a gas furnace (short bursts of hot air from the vents) better than the HP experience (steadily blowing air that is very slightly warmer than the room air) there's no reason not to get another Gas/AC combo. The higher efficiency units tend to take up more space and high-efficiency furnaces require special venting, so that's a consideration if your current unit is squeezed into a closet.

3) Pick up a used window AC from Craigslist, Facebook, etc. to get you through this summer. Get more than 5k BTU if possible, or consider getting 2 window units depending on the size and layout of your house and your sensitivity to noise. Even at R-10, these will actually be more efficient to run this summer than your 20+ year old AC with low refrigerant. You might save a couple hundred dollars on electricity by making this move, and you'll resale these used units next summer for the same amount you paid. Most importantly, you don't get stranded when your central AC goes out in the middle of this summer. Low refrigerant means the AC is about to go out!

4) Time the replacement of your HVAC for the least-busy time for installers. So you're looking at Springtime 2024. You'll get a better deal, speedier service, and better installation quality at this time than in the dead of winter or peak of summer when most people request service and the techs are working in the cold or heat. Plus you have time to special order parts and stuff, if necessary, to obtain the ideal setup. This timing also squeezes out the last bits of utility from your ancient furnace. Furnaces are much simpler and less likely to go out, so I think you'll make it through this winter.

5) Make sure you replace the air filters. Poor air flow reduces efficiency by a lot.

[FINate]

I really am skeptical about whether a heat pump can handle my house yet. All the people I've talked to online who have heat pumps and say they work fine have modern houses. There's a huge difference between my 1918 house and their 1980 house. They are simply not comparable in many ways. And I haven't found people with the old house and a well functioning heat pump.

This was the pattern with the folks I talked with. Well sealed envelope with good insulation (e.g. modern construction) and a HP is great. But a big drafty house... even the new HPs struggled to put out enough heat to keep it comfortable. How HVAC is spec'd and installed matters a great deal, and this is difficult to determine moving to a HP without something like an energy audit / blower door test. This wasn't an option for us when we replaced our HVAC, and I wasn't about to go with a fly-by-night operation that would be happy to install an HP but maybe not be around to stand behind their work over the long term.

[uniwelder]

I really am skeptical about whether a heat pump can handle my house yet. All the people I've talked to online who have heat pumps and say they work fine have modern houses. There's a huge difference between my 1918 house and their 1980 house. They are simply not comparable in many ways. And I haven't found people with the old house and a well functioning heat pump.

This was the pattern with the folks I talked with. Well sealed envelope with good insulation (e.g. modern construction) and a HP is great. But a big drafty house... even the new HPs struggled to put out enough heat to keep it comfortable. How HVAC is spec'd and installed matters a great deal, and this is difficult to determine moving to a HP without something like an energy audit / blower door test. This wasn't an option for us when we replaced our HVAC, and I wasn't about to go with a fly-by-night operation that would be happy to install an HP but maybe not be around to stand behind their work over the long term.

If you have an existing system (as opposed to new construction) to compare against, it shouldn't be a big deal to size out replacement equipment.  You just need to look at how much energy your current system uses on the coldest day.  Hopefully you can see that real time, like power or gas company records if available, or going outside to read the meter.  Something else you can do is record how often the gas furnace kicks on and how long it runs for, and look at the furnace specs to see how many btu's its rated for.  For example, on the coldest day of the year, it runs for 45 minutes of an hour and its rated for 60k btu/hr and its an 80% efficient furnace, so you need a (45/60)*(60)*(.80)= 36k btu heat pump at that temp.  Heat pumps are going to be rated a temperature higher than your coldest temp, so you (or the hvac company) needs to read up on the specs to make sure it can put out the necessary heat at your cold temperature.

I think the real problem FINate's neighbors are encountering doesn't have to do with heat pumps, but incompetent hvac companies.  Most hvac techs don't want to do any sort of useful calculation.

[Sibley]

I really am skeptical about whether a heat pump can handle my house yet. All the people I've talked to online who have heat pumps and say they work fine have modern houses. There's a huge difference between my 1918 house and their 1980 house. They are simply not comparable in many ways. And I haven't found people with the old house and a well functioning heat pump.

This was the pattern with the folks I talked with. Well sealed envelope with good insulation (e.g. modern construction) and a HP is great. But a big drafty house... even the new HPs struggled to put out enough heat to keep it comfortable. How HVAC is spec'd and installed matters a great deal, and this is difficult to determine moving to a HP without something like an energy audit / blower door test. This wasn't an option for us when we replaced our HVAC, and I wasn't about to go with a fly-by-night operation that would be happy to install an HP but maybe not be around to stand behind their work over the long term.

If you have an existing system (as opposed to new construction) to compare against, it shouldn't be a big deal to size out replacement equipment.  You just need to look at how much energy your current system uses on the coldest day.  Hopefully you can see that real time, like power or gas company records if available, or going outside to read the meter.  Something else you can do is record how often the gas furnace kicks on and how long it runs for, and look at the furnace specs to see how many btu's its rated for.  For example, on the coldest day of the year, it runs for 45 minutes of an hour and its rated for 60k btu/hr and its an 80% efficient furnace, so you need a (45/60)*(60)*(.80)= 36k btu heat pump at that temp.  Heat pumps are going to be rated a temperature higher than your coldest temp, so you (or the hvac company) needs to read up on the specs to make sure it can put out the necessary heat at your cold temperature.

I think the real problem FINate's neighbors are encountering doesn't have to do with heat pumps, but incompetent hvac companies.  Most hvac techs don't want to do any sort of useful calculation.

I will be limited to whatever the utility has on their website. We didn't hit -22 last winter, but did have some quite negative days. Will research.

And based on the 2 companies I've talked to so far, competence is going to be an issue.

I also think I will get an energy audit, assuming it's not terribly expensive. Maybe I'll get lucky and it'll be free. It would be nice to get some data to guide priority if nothing else.

[Dancin'Dog]

I can't imagine trying to heat or cool a home without insulated walls.  It seems like installing a layer of foam board on the walls would make a huge difference in the load on the HVAC.  Wonder if there are any tax incentives to help with insulation?

[Bartlebooth]

I live in an 1890 house in North Dakota with uninsulated walls.  There is about 1/4" of foam board underneath the steel siding if that counts.  The partial attic is ~R15 insulation.

Heating costs are 2-3x what a similarly sized house would be.  $500-1000 wasted heating cost per year maybe?  Enough that it hurts, but not enough to make me gut the house and insulate it.  The walls are only 2x4 anyways so can't fit a ton of insulation in there.

[uniwelder]

I live in an 1890 house in North Dakota with uninsulated walls.  There is about 1/4" of foam board underneath the steel siding if that counts.  The partial attic is ~R15 insulation.

Heating costs are 2-3x what a similarly sized house would be.  $500-1000 wasted heating cost per year maybe?  Enough that it hurts, but not enough to make me gut the house and insulate it.  The walls are only 2x4 anyways so can't fit a ton of insulation in there.

Was that a typo, or are you saying the typical house in North Dakota only costs $500/year to heat?

[Sibley]

I can't imagine trying to heat or cool a home without insulated walls.  It seems like installing a layer of foam board on the walls would make a huge difference in the load on the HVAC.  Wonder if there are any tax incentives to help with insulation?

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

I'm sorry, but a tax credit for $1k or whatever isn't enough to incentivize me to do this project. It would be a nice side bonus to the project I already decided to do. And this project is not on the short or medium term list. The house is functional.

However, I have plaster on an early form of blue board, so while it's not insulated it's better than drywall + no insulation would be.

-----
Delay, delay. HVAC tech is having transportation difficulties, so he's coming Tuesday now.

[Dancin'Dog]

I can't imagine trying to heat or cool a home without insulated walls.  It seems like installing a layer of foam board on the walls would make a huge difference in the load on the HVAC.  Wonder if there are any tax incentives to help with insulation?

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

I'm sorry, but a tax credit for $1k or whatever isn't enough to incentivize me to do this project. It would be a nice side bonus to the project I already decided to do. And this project is not on the short or medium term list. The house is functional.

However, I have plaster on an early form of blue board, so while it's not insulated it's better than drywall + no insulation would be.

-----
Delay, delay. HVAC tech is having transportation difficulties, so he's coming Tuesday now.

That's much better than "no insulation".  Foam doesn't have high R ratings, but it's still quite an impressive material.


Consider a styrofoam coffee cup.  It's less than 1/8" thick, yet it allows you to hold almost boiling-hot liquid in your hand.  That's pretty amazing. 


Btw, you can actually boil water in a foam cup over a fire.  I couldn't believe it until someone showed me.

[Sibley]

I can't imagine trying to heat or cool a home without insulated walls.  It seems like installing a layer of foam board on the walls would make a huge difference in the load on the HVAC.  Wonder if there are any tax incentives to help with insulation?

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

I'm sorry, but a tax credit for $1k or whatever isn't enough to incentivize me to do this project. It would be a nice side bonus to the project I already decided to do. And this project is not on the short or medium term list. The house is functional.

However, I have plaster on an early form of blue board, so while it's not insulated it's better than drywall + no insulation would be.

-----
Delay, delay. HVAC tech is having transportation difficulties, so he's coming Tuesday now.

That's much better than "no insulation".  Foam doesn't have high R ratings, but it's still quite an impressive material.


Consider a styrofoam coffee cup.  It's less than 1/8" thick, yet it allows you to hold almost boiling-hot liquid in your hand.  That's pretty amazing. 


Btw, you can actually boil water in a foam cup over a fire.  I couldn't believe it until someone showed me.

Earlier than that. Basically, compressed cardboard. It's got a name, I forget. Cellulose and glue, tested and confirmed no asbestos.

[Jon Bon]

I 20 year old furnace might yet still have some life left in it.

I would not go heap pump only in your area climate zone 5 I assume?

I am in climate zone 5 and have 2 heating zones, one is a new furnace and the other is a new heat pump. Now they do make efficient HPs that can work in colder temperatures, but you pay a premium for those. Mine craps out about 10 degrees and I basically just turn if off, and turn my furnace up a degree. Honestly does not feel all that different and I don't have to hear my HP struggle and eat kilowatts to really not do much heating.

The "Cold Air" aspect of a HP takes some getting used to. A gas furnace pushes out air that is >100 degrees and feels warm and dry. A HP on cold days might only push out air a few degrees warmer than room temp. So it can feel like you are running a ceiling fan. Yes it heats, but it can be a bit uncomfortable.

So if you want to keep the furnace and use it 10 coldest days a year? that would probably be a good middle ground. Heat pumps are pretty cool, and they work great! (until they dont...)

[Jon Bon]

OH yeah back to insulation.

if you have zero insulation in your walls, your house is NOT R-0. There are websites that you can build your wall layers and it will tell you what your insulation value is.

If the air is well sealed in a 2x4 wall that would be r -3.5 If you add in your exterior sheeting, and interior wall board it gets a bit higher than you would expect. Still not good, but better than nothing.

Blown in cellulose is your friend FYI. Its a DIY with a bit ROI.

https://www.ekotrope.com/r-value-calculator

[ChpBstrd]

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

Some cellulose blowers and foam injection contractors will install from the inside. This would mean you merely have some drywall patching and painting to do instead of tearing apart the much more complicated exterior surfaces. See for example https://www.retrofoam.com/install-process.

If you have balloon style framing, even easier.

Honestly though, I'm looking at this option as an excuse to pull all the drywall down, rewire everything easily, get rid of a bunch of lead based paint, and have actually smooth walls after all is said and done.

[Sibley]

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

Some cellulose blowers and foam injection contractors will install from the inside. This would mean you merely have some drywall patching and painting to do instead of tearing apart the much more complicated exterior surfaces. See for example https://www.retrofoam.com/install-process.

If you have balloon style framing, even easier.

Honestly though, I'm looking at this option as an excuse to pull all the drywall down, rewire everything easily, get rid of a bunch of lead based paint, and have actually smooth walls after all is said and done.

Old houses do not work the same way as new houses. You can not treat them the same way. If you ever buy an old building (40s or prior), then you need to do a lot of research. Because you are wrong, and doing what you suggest would cause serious damage.

These buildings DO NOT have vapor barriers. Water gets in. They rely on the air gaps to manage moisture. If you look at the inside of the walls, you'll find evidence of old water staining. Staining, and not damage, because the air gaps mean the moisture was able to dry out. If you put cellulous or fiberglass insulation in the walls without addressing the lack of a vapor barrier, the result will be wet insulation, which will cause rot. You will quite literally rot the walls from the inside out given sufficient time.

If you don't want to take the siding down, then you gut the building. Because you need the walls open. Then, you can use rockwool batts (it doesn't come in blown-in as far as I know because it's too heavy) to insulate. Rockwool is hydrophobic, it'll get wet but not retain the water. Or you can use foam (I forget if its open or closed cell which acts as a vaper barrier, so make sure you do the research and use the correct one or you're back to rotting the walls). If you don't want to gut the building, then you have to go from the exterior, which involves removing the existing siding.

https://www.youtube.com/watch?v=_RQ9S1u7ag4

[Sibley]

HVAC tech was here and actually looked at the condition of the ac. Interesting knowledge: the furnace is from 1994, the ac from 2005. Yes, my furnace is almost 30 years old. The ac is almost old enough to drink! AC is a 3 ton, furnace is 75,000 BTU 80% efficiency.

The ac is in really good condition. The guy was very surprised that it was as old as it is, apparently prior owners have been pretty decent at maintenance or at least not mechanical abuse, and I have done annual maintenance/repair since I bought the house. He confirmed that the refrigerant was low and agreed with the 1-3 lbs estimate from the other company, though he thought probably on the lower end. He attempted to locate the leak, but was unsuccessful in specifically locating it. Which means, it's in the A frame. So, we tried to look at the A frame. We weren't able to get the cover completely off without taking a bunch of stuff apart, so we had to be satisfied with peeking from the side. The A frame is rusty, but not falling to bits rusty. The guy also thought it looked decent.

Thus: we recharged it, and I'll continue with my plan to replace both units in 2024. He put in about 1.5lbs of R22. This will hopefully get me through the summer, and I'll replace both units in April/May 2024.

----
I also had a HVAC company come do an estimate on a new system today. I asked for quotes on an 80% furnace and whatever is standard for the ac, which turned out to be 14 SEER2. He also quoted at 15 and 16 SEER2 on the ac. As much as I'd like to get more efficient, realistically, my house isn't that efficient. It would be a waste of money.

Note: apparently SEER2 is the brand new rating system for efficiency, it's replacing SEER. New since the last month or so. I am not researching this, do not care right now.

It is also very possible that the current ac is oversized for the ductwork/house, which explains why there's a giant hole cut into the side of the return air box. The system needs more air supply, unfortunately doing it that way resulted in sucking exhaust out of the water heater so I had to block the giant hole. When I replace next year, this will be a consideration.

I also should get into the crawl space and work on improving that area. That is the next last big area of air sealing/insulation that I can tackle without it being a major project. Previous owners tried to address the cold winter floors except they did it wrong, so I need to remove a bunch of insulation and redo things properly. Luckily, what they did isn't really terrible so it hasn't caused damage, but it's also not right. This will not be fun, not least because the entry is about 2x3 feet and I can't get out without assistance.

[scottish]

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

Some cellulose blowers and foam injection contractors will install from the inside. This would mean you merely have some drywall patching and painting to do instead of tearing apart the much more complicated exterior surfaces. See for example https://www.retrofoam.com/install-process.

If you have balloon style framing, even easier.

Honestly though, I'm looking at this option as an excuse to pull all the drywall down, rewire everything easily, get rid of a bunch of lead based paint, and have actually smooth walls after all is said and done.

Old houses do not work the same way as new houses. You can not treat them the same way. If you ever buy an old building (40s or prior), then you need to do a lot of research. Because you are wrong, and doing what you suggest would cause serious damage.

These buildings DO NOT have vapor barriers. Water gets in. They rely on the air gaps to manage moisture. If you look at the inside of the walls, you'll find evidence of old water staining. Staining, and not damage, because the air gaps mean the moisture was able to dry out. If you put cellulous or fiberglass insulation in the walls without addressing the lack of a vapor barrier, the result will be wet insulation, which will cause rot. You will quite literally rot the walls from the inside out given sufficient time.

If you don't want to take the siding down, then you gut the building. Because you need the walls open. Then, you can use rockwool batts (it doesn't come in blown-in as far as I know because it's too heavy) to insulate. Rockwool is hydrophobic, it'll get wet but not retain the water. Or you can use foam (I forget if its open or closed cell which acts as a vaper barrier, so make sure you do the research and use the correct one or you're back to rotting the walls). If you don't want to gut the building, then you have to go from the exterior, which involves removing the existing siding.

https://www.youtube.com/watch?v=_RQ9S1u7ag4

That's a good video.    But I don't get how you could add insulation without opening up the *inside* as well as the outside - there needs to be a vapor barrier on the inside to prevent humidity from entering the wall from the inside and condensing in the insulation.   Would you just stable the vapour barrier to the studs after you take the siding off and before installing insulation?

[Sibley]

In order to insulate my house, I need to take off the exterior siding, fix whatever is wrong (rotten wood, etc), cut holes in the wood siding that's under the aluminum siding, blow in insulation, probably put foam board on, then vapor barrier, then new siding. Or similar process. Even putting foam board on, which doesn't do much in terms of R-value, requires removing the siding, fixing whatever is found, foam board, vapor barrier, and new siding.

Some cellulose blowers and foam injection contractors will install from the inside. This would mean you merely have some drywall patching and painting to do instead of tearing apart the much more complicated exterior surfaces. See for example https://www.retrofoam.com/install-process.

If you have balloon style framing, even easier.

Honestly though, I'm looking at this option as an excuse to pull all the drywall down, rewire everything easily, get rid of a bunch of lead based paint, and have actually smooth walls after all is said and done.

Old houses do not work the same way as new houses. You can not treat them the same way. If you ever buy an old building (40s or prior), then you need to do a lot of research. Because you are wrong, and doing what you suggest would cause serious damage.

These buildings DO NOT have vapor barriers. Water gets in. They rely on the air gaps to manage moisture. If you look at the inside of the walls, you'll find evidence of old water staining. Staining, and not damage, because the air gaps mean the moisture was able to dry out. If you put cellulous or fiberglass insulation in the walls without addressing the lack of a vapor barrier, the result will be wet insulation, which will cause rot. You will quite literally rot the walls from the inside out given sufficient time.

If you don't want to take the siding down, then you gut the building. Because you need the walls open. Then, you can use rockwool batts (it doesn't come in blown-in as far as I know because it's too heavy) to insulate. Rockwool is hydrophobic, it'll get wet but not retain the water. Or you can use foam (I forget if its open or closed cell which acts as a vaper barrier, so make sure you do the research and use the correct one or you're back to rotting the walls). If you don't want to gut the building, then you have to go from the exterior, which involves removing the existing siding.

https://www.youtube.com/watch?v=_RQ9S1u7ag4

That's a good video.    But I don't get how you could add insulation without opening up the *inside* as well as the outside - there needs to be a vapor barrier on the inside to prevent humidity from entering the wall from the inside and condensing in the insulation.   Would you just stable the vapour barrier to the studs after you take the siding off and before installing insulation?

Vapor barrier goes on the exterior, not the interior. Think of new construction - from outside-in I believe you have siding, housewrap, sheathing, insulation, drywall.

You are severely limited in the types of insulation you can use. The correct type of foam will act as a vapor barrier as well as insulator. With rockwool (brand name for mineral wool), it works because the stuff is hydrophobic, not because there's no moisture. I'm not sure if there's other options that add a vapor barrier from the inside which allow for other insulation types, but if you really are curious watch a bunch of the last 5-10 years of This Old House episodes. If there is, they've discussed it. Even doing it this way though, it won't be as tight as if you added a vapor barrier to the exterior.

The problems of insulating these old houses wrong are not immediate, you can go years before serious rot develops. There are a lot of houses in the US which are ticking time bombs because someone decided to insulate and they just blew in cellulose. My parent's old house is one of them. Eventually, the studs are going to rot. But its expensive to do it right - rockwool is more expensive than fiberglass, and the foam at least used to be the more expensive type, and it's a LOT more labor. Blowing in celluous is cheap, fast and easy.

In general, the key to understanding what you can and can not do with an old house is understanding how it was built. If you have that base knowledge you can logic through the implications of whatever you want to do.

[Dancin'Dog]

It sounds like "the cure is more painful than the disease" type of situation.   Or, "easier to bear than to repair".  <grin>

[Bartlebooth]

Vapor barrier goes on the exterior, not the interior. Think of new construction - from outside-in I believe you have siding, housewrap, sheathing, insulation, drywall.

Hmm, in cold climates that require heating I believe that moisture barrier on the interior is the requirement.  Between the drywall and the insulation, it keeps the moist inside air from condensing in the insulation where the moist air would otherwise cool and condense.  And isn't housewrap a water barrier that breathes (allows water vaper to dissipate outwards, maybe a half vapor barrier)?

Edit: oops I trimmed scottish's text which I guess says basically the same thing.  I side with him!

[Bartlebooth]

I live in an 1890 house in North Dakota with uninsulated walls.  There is about 1/4" of foam board underneath the steel siding if that counts.  The partial attic is ~R15 insulation.

Heating costs are 2-3x what a similarly sized house would be.  $500-1000 wasted heating cost per year maybe?  Enough that it hurts, but not enough to make me gut the house and insulate it.  The walls are only 2x4 anyways so can't fit a ton of insulation in there.

Was that a typo, or are you saying the typical house in North Dakota only costs $500/year to heat?

There is quite a lot of slop in my ranges.  For highest typical house value, say my heating costs are 2x and $1000 wasted ( typical * 2 = typical + 1000 ) which means I am thinking typical heating cost is $1000/year.  A modest house that is reasonably insulated should definitely have heating bills less than that ($142/month over 7 months).  The other extreme is less likely: 3x and $500 wasted ( typical * 3 = typical + 500 ) would be $250 per year.

[Sibley]

Vapor barrier goes on the exterior, not the interior. Think of new construction - from outside-in I believe you have siding, housewrap, sheathing, insulation, drywall.

Hmm, in cold climates that require heating I believe that moisture barrier on the interior is the requirement.  Between the drywall and the insulation, it keeps the moist inside air from condensing in the insulation where the moist air would otherwise cool and condense.  And isn't housewrap a water barrier that breathes (allows water vaper to dissipate outwards, maybe a half vapor barrier)?

Edit: oops I trimmed scottish's text which I guess says basically the same thing.  I side with him!

I know old houses, not new houses. My wall outside-in is aluminum siding, wood siding, studs, backerboard and plaster.

[Dancin'Dog]

Vapor barrier goes on the exterior, not the interior. Think of new construction - from outside-in I believe you have siding, housewrap, sheathing, insulation, drywall.

Hmm, in cold climates that require heating I believe that moisture barrier on the interior is the requirement.  Between the drywall and the insulation, it keeps the moist inside air from condensing in the insulation where the moist air would otherwise cool and condense.  And isn't housewrap a water barrier that breathes (allows water vaper to dissipate outwards, maybe a half vapor barrier)?

Edit: oops I trimmed scottish's text which I guess says basically the same thing.  I side with him!

I know old houses, not new houses. My wall outside-in is aluminum siding, wood siding, studs, backerboard and plaster.

Have you considered contacting This Old House to see if they'd like to do a season on your house?  Pete would be proud!


;~)

[Sibley]

Vapor barrier goes on the exterior, not the interior. Think of new construction - from outside-in I believe you have siding, housewrap, sheathing, insulation, drywall.

Hmm, in cold climates that require heating I believe that moisture barrier on the interior is the requirement.  Between the drywall and the insulation, it keeps the moist inside air from condensing in the insulation where the moist air would otherwise cool and condense.  And isn't housewrap a water barrier that breathes (allows water vaper to dissipate outwards, maybe a half vapor barrier)?

Edit: oops I trimmed scottish's text which I guess says basically the same thing.  I side with him!

I know old houses, not new houses. My wall outside-in is aluminum siding, wood siding, studs, backerboard and plaster.

Have you considered contacting This Old House to see if they'd like to do a season on your house?  Pete would be proud!


;~)

If they pay for it, 1000%. I don't think it works that way though.

[Sibley]

The AC died. Educated guess is a coolant line broke and then all the electronics got fried. I noticed it wasn't cooling off in the house so checked on it, it wasn't running. Turned it off. Given the burning smell, the oil on the ground, the hissing of the coolant.... it's dead. Also turned off the power to it so it's basically scrap.

I'm going to try for a duel fuel system: heat pump for cooling and parts of the heating season, 80% furnace for the rest. If I can't get a heat pump then will get standard ac, which will be significantly more efficient than the dead one.

It will of course be hot this week so please send cool thoughts. And rain, or at least clouds.

[nereo]

The AC died. Educated guess is a coolant line broke and then all the electronics got fried. I noticed it wasn't cooling off in the house so checked on it, it wasn't running. Turned it off. Given the burning smell, the oil on the ground, the hissing of the coolant.... it's dead. Also turned off the power to it so it's basically scrap.

I'm going to try for a duel fuel system: heat pump for cooling and parts of the heating season, 80% furnace for the rest. If I can't get a heat pump then will get standard ac, which will be significantly more efficient than the dead one.

It will of course be hot this week so please send cool thoughts. And rain, or at least clouds.

Why not use a ducted heat pump for all your heating and cooling needs since you need a full replacement. What benefits do you see to adding a second system and duel fuel?

[Sibley]

The AC died. Educated guess is a coolant line broke and then all the electronics got fried. I noticed it wasn't cooling off in the house so checked on it, it wasn't running. Turned it off. Given the burning smell, the oil on the ground, the hissing of the coolant.... it's dead. Also turned off the power to it so it's basically scrap.

I'm going to try for a duel fuel system: heat pump for cooling and parts of the heating season, 80% furnace for the rest. If I can't get a heat pump then will get standard ac, which will be significantly more efficient than the dead one.

It will of course be hot this week so please send cool thoughts. And rain, or at least clouds.

Why not use a ducted heat pump for all your heating and cooling needs since you need a full replacement. What benefits do you see to adding a second system and duel fuel?

Because I know my house, I know my climate, and every scrap of research and first hand experience I can find tells me that a heat pump is not going to keep the house warm in the coldest temps. I'm not saying that they can't handle the climate - I'm saying that can't handle MY HOUSE in the climate. Not without oversizing it in a way that is detrimental overall. I would love to put in the most efficient and environmentally friendly hvac systems. It doesn't make sense.

There's also the other problem of heat pumps are not that popular in my area yet. The number of HVAC companies that install and service them are in the single digits. It's such a limited number that I'm not actually sure I will be able to get a heat pump. Even if I expand to Illinois it's not a large number, and there's no guarantee they'll come to my area.

I'm trying to arrange pickup/drop off of a window ac unit which I can borrow from a friend. He's swamped today which is difficult. That will enable me to not melt this week.

[nereo]

What questions, if any, do you have here now?

[Dancin'Dog]

I've replaced two heat pumps in the past two years.  Last year I chose a Carrier, since I was familiar with the brand & the unit looked similar to the original I was replacing.  This year I called an independent HVAC guy, instead of a company with a dozen vans & billboard advertising.  He recommended a Goodman.  He said it's a simpler design, he has fewer callbacks, and it's about 25% less expensive than a Carrier.  I didn't like the housing color was much darker than the Carrier, but since they're behind the house nobody will really notice, so I decided to try a Goodman.  The total price was $6400 for a 2.5 Ton compared to $8500 for a Carrier. 


It seems that the parts are available for about 50% of the installed price, but you need to get certified to order them.  The removal & installation only takes about 5 hours, but it requires a helper for a little while during the heavy lifting.  (The independent guy recruited his electrician buddy that came to confirm the breaker was properly sized.)  $3200 for 5 hours seems like a darned good day for a blue-collar career.  I'd highly encourage young people looking for "something to get into" to consider HVAC. 

[Sibley]

What questions, if any, do you have here now?

I appreciate it when people come back to update, so that's what I did.

[GilesMM]

The AC died. Educated guess is a coolant line broke and then all the electronics got fried. I noticed it wasn't cooling off in the house so checked on it, it wasn't running. Turned it off. Given the burning smell, the oil on the ground, the hissing of the coolant.... it's dead. Also turned off the power to it so it's basically scrap.

I'm going to try for a duel fuel system: heat pump for cooling and parts of the heating season, 80% furnace for the rest. If I can't get a heat pump then will get standard ac, which will be significantly more efficient than the dead one.

It will of course be hot this week so please send cool thoughts. And rain, or at least clouds.

What kind of oil does your unit use? Mine doesn’t use oil at all except a bit of occasional lubricant on the fan. Are you sure coolant sprayed on the electronics and shorted them? You can test that with a meter.

[Sibley]

The AC died. Educated guess is a coolant line broke and then all the electronics got fried. I noticed it wasn't cooling off in the house so checked on it, it wasn't running. Turned it off. Given the burning smell, the oil on the ground, the hissing of the coolant.... it's dead. Also turned off the power to it so it's basically scrap.

I'm going to try for a duel fuel system: heat pump for cooling and parts of the heating season, 80% furnace for the rest. If I can't get a heat pump then will get standard ac, which will be significantly more efficient than the dead one.

It will of course be hot this week so please send cool thoughts. And rain, or at least clouds.

What kind of oil does your unit use? Mine doesn’t use oil at all except a bit of occasional lubricant on the fan. Are you sure coolant sprayed on the electronics and shorted them? You can test that with a meter.

Giles, it's a 20 year old AC unit. It nearly caught on fire. I was willing to try to limp it along earlier this summer so I could replace it in the spring as planned. Trying to fix now it would be a waste of money.

And I don't know where the oil came from, just that it was oil. It wasn't much.

[ChickenStash]

Regarding the oil, the refrigerant has a few ounces of oil suspended in it to lubricate the compressor as the unit runs - the amount and type of oil varies based on the refrigerant type and system design. It sounds like there was a major leak so all the escaping refrigerant would have carried much of that oil with it and when the gas dissipated the oil would have been left behind.

[Sibley]

New furnace and heat pump were installed on Friday. Just in time for more hot weather. So far all is working well. Looking forward to not needing to worry about the hvac for years, beyond regular maintenance.

[TomTX]

Because I know my house, I know my climate, and every scrap of research and first hand experience I can find tells me that a heat pump is not going to keep the house warm in the coldest temps. I'm not saying that they can't handle the climate - I'm saying that can't handle MY HOUSE in the climate. Not without oversizing it in a way that is detrimental overall. I would love to put in the most efficient and environmentally friendly hvac systems. It doesn't make sense.

Well, apparently it's all too late now - but rather than a furnace that won't get used much I'd look at using a handful of electric space heaters as supplemental heat for the handful of days it's too cold for a modern heat pump.

[NorCal]

I can speak to heat pumps.  I had a cold weather unit installed about a year ago, and it kept my house warm when it was -16 out.  But my house was better insulated than yours.  Less insulation needs a bigger unit, regardless of what type of furnace you go with.

View insulation and HVAC as a single project.  The more insulation you add, the less HVAC you need. 

I've posted a promotional video from Mr Cool below.  They installed a heat pump in North Dakota and it kept the house warm at -24 out.  There are brands that will work in your climate.  However, most traditional HVAC techs are only familiar with the ones that need a backup.  Get at least one quote from a company that specializes in a true cold weather brand.  Mitsubishi is well known here for cold weather capabilities and they are very efficient.  They also happen to be more expensive though.

I have a friend that is also getting a cold weather heat pump.  The installer gave them a choice.  They could get a unit with backup heat, or they could go without backup heat and use space heaters for the couple days a year it gets well into sub-zero temperatures.  There was a $3k difference between these, making a few space heaters worth the money.  The heat pump would still be functional at those temperatures, it would just need a boost. 

I'm happy to answer any specific questions you have on cold weather heat pumps.  I'm finding myself coming back to these threads less frequently, so feel free to DM me as well. 


https://www.youtube.com/watch?v=_v8vizQXwss&t=25s

[AccidentialMustache]

I wish our unit that died a few years ago had hung on just a bit longer. I'd love to have something better than our kinda stupid trane. Alas, it did not and between the price of the A frame and the R22, yeah, we just replaced it.

I do like the electric resistance backup heat though. Not because I want to use it during the year, I'd rather size up the unit, but that stuff is cheap to install (at least in the standard us brand units) and means that if your compressor dies during polar vortex you can still heat the house. By burning money at a prodigious rate, but you'll stay warm!