Author Topic: Help with HVAC Options  (Read 1323 times)

treefly

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Help with HVAC Options
« on: January 18, 2023, 10:13:39 AM »
Hello, I want to request some help on some HVAC + insulation choices:

We (Me, Wife, 2yr old, 6mo) live in a 3500 sq ft home in the upstate of SC, built in 1950. We currently have a 2-zone HVAC with a 3 ton 12 seer system(I think) each upstairs and downstairs. The outdoor units are from 1990 and the furnaces are 80,000 btu units, 92% efficiency, which were installed in 2006. I assume the efficiency of all the units has gone way down since installation, but I'm not sure how much.

Currently the upstairs ducts are duct board with flex tube to the vents, while the downstairs is metal to the end. Only one return upstairs, but downstairs has a separate return for each room. Our total utilities bill is $4,500ish, and I estimated a heating load of 74 mil BTUs and 13 mil BTUs of cooling. I try to keep the thermostat at a reasonable level, 67 in winter, 78 in summer.

The attic insulation is very poor, maybe 2-3in, and I am currently working on sealing the house. I am unsure of how to measure the wall insulation, and the house has an unfinished, uninsulated basement. I am also in the process of replacing the windows, and they seem to be really poorly sealed too. 

I got a HVAC company to come in and check the units as they are quite old, and they gave me the following estimates for replacing the systems:

Option 1:
Replace AC units with 16 Seer units(York YCG), upgrade electrical to current code: $11,253
   I assume these units are also 3 ton, but the quote did not specify

Option 2:
Option 1 plus switch out furnaces for 80,000 BTU 96% ones: $17,119

Option 3:
Change to 19 Seer 3 ton, 2 stage heat pump(York YZT) paired with 96% furnace: $22,453
   For this one, I could get the 30% tax break up to $2k, so it's really $20k.

Obviously, I need to work on the sealing and insulation, but I wanted to get y’alls advice on how much I can reduce my heating and cooling load by doing that, and if you would replace the furnace as well as the AC, as those are pretty clearly on borrowed time. We plan on living in this house at least until the kids are out of the house, so we’ve got a pretty long timeframe.

affordablehousing

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Re: Help with HVAC Options
« Reply #1 on: January 19, 2023, 10:24:33 AM »
I would just focus on the insulation and air sealing, and on wearing jackets to get your thermostat down to 63 in the winter. Is the $4,500 just for gas / cooling electric? or include all other utilities? If it includes all others, I would only replace the systems when they break down. Of all the components, you may save some money on doing the furnace swap yourself if you have good access.

chemistk

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Re: Help with HVAC Options
« Reply #2 on: January 19, 2023, 11:46:16 AM »
Your A/C units are definitely on borrowed time, and you would do well to replace them when they're still functional rather than wait until they stop working. You'll have the benefit of being able to purchase whichever replacement system you settle on in a timeframe that aligns with supply chains, your schedule, and the installer's schedule. That's much more advantageous than having them down during a summer heat wave and trying to get the HVAC company in ASAP.

I'd get some other quotes on other systems, especially with the complexity of your configuration. You might end up with the HVAC company you initially contacted, or you might find that another is more desirable.

In the meantime, it's definitely to your advantage to work on increasing the R-value, at a minimum, in your attic space. Blown in insulation is relatively affordable, especially considering its immediate returns. As for the walls, that can get much more expensive - the best way to tell what the insulation looks like in your walls is to cut a hole in the wall and peek inside to see what's in there. If you do end up trying to add more insulation/air sealing in the walls, you're looking at professionally applied spray foam. With your current HVAC costs, that could make sense, but you won't know what you need and what it would cost until you actually have an idea of where the walls are now.

I'd investigate option 4: Install two heat pump units with accompanying electrical work while keeping your existing gas furnace. You certainly don't need 19SEER heat pumps, especially in your climate, so I'd expect the cost on that setup to be between options 1 and 2.

Being in SC, I think you'll find that the heat pumps will be able to handle the vast majority of your heating needs. You or the HVAC company can set the threshold where the furnace is engaged in the high 30's or low 40's, and you and your family will probably never notice the fact that the heat pumps are doing the heating work 90% of the time.


treefly

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Re: Help with HVAC Options
« Reply #3 on: January 19, 2023, 12:33:12 PM »
Your A/C units are definitely on borrowed time, and you would do well to replace them when they're still functional rather than wait until they stop working. You'll have the benefit of being able to purchase whichever replacement system you settle on in a timeframe that aligns with supply chains, your schedule, and the installer's schedule. That's much more advantageous than having them down during a summer heat wave and trying to get the HVAC company in ASAP.

I'd get some other quotes on other systems, especially with the complexity of your configuration. You might end up with the HVAC company you initially contacted, or you might find that another is more desirable.

In the meantime, it's definitely to your advantage to work on increasing the R-value, at a minimum, in your attic space. Blown in insulation is relatively affordable, especially considering its immediate returns. As for the walls, that can get much more expensive - the best way to tell what the insulation looks like in your walls is to cut a hole in the wall and peek inside to see what's in there. If you do end up trying to add more insulation/air sealing in the walls, you're looking at professionally applied spray foam. With your current HVAC costs, that could make sense, but you won't know what you need and what it would cost until you actually have an idea of where the walls are now.

I'd investigate option 4: Install two heat pump units with accompanying electrical work while keeping your existing gas furnace. You certainly don't need 19SEER heat pumps, especially in your climate, so I'd expect the cost on that setup to be between options 1 and 2.

Being in SC, I think you'll find that the heat pumps will be able to handle the vast majority of your heating needs. You or the HVAC company can set the threshold where the furnace is engaged in the high 30's or low 40's, and you and your family will probably never notice the fact that the heat pumps are doing the heating work 90% of the time.



So the option 4 idea is to have the two heat pumps be able to take over for the furnaces whenever it goes out? The environmentalist/efficency nerd part of me wants to get rid of the gas line entirely, but I'm not sure if that's actually economical or not. Do you think I should replace the furnace units as well?

@affordablehousing the $4500 is for all utilities, but I subtracted out the "normal" electrical use from the part of the year we use heating to attempt to find how much is used for cooling.

I do wonder how much I can reduce my heating and cooling loads, and how much that will affect what I need. Not sure how to estimate that without getting someone to do a blower door test.

Also, should I look into replacing my ductwork upstairs? I've thought about getting them sealed or doing it myself, but maybe ductboard is bad enough to completely replace?

chemistk

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Re: Help with HVAC Options
« Reply #4 on: January 19, 2023, 01:16:27 PM »
So the option 4 idea is to have the two heat pumps be able to take over for the furnaces whenever it goes out? The environmentalist/efficency nerd part of me wants to get rid of the gas line entirely, but I'm not sure if that's actually economical or not. Do you think I should replace the furnace units as well?

On the contrary, you would actually primarily rely on the heat pumps for heating in all but the coldest temperatures, usually when the COP drops below 2-2.5 depending on the overall performance of the heat pumps you'd buy.

This assumes that your electrical rates aren't absurdly high but consider that in many areas, heat pumps are the primary heating system being installed in new residential construction.

Without knowing your specific utility rates, as well as your actual usage, no assumptions about cost can be made other than 'it's probably not going to cost more than what you currently pay'.

By relying more on heat pumps, you'd be extending the life of your furnace and avoiding incurring that replacement cost, while also reducing your gas usage.


@affordablehousing the $4500 is for all utilities, but I subtracted out the "normal" electrical use from the part of the year we use heating to attempt to find how much is used for cooling.

I do wonder how much I can reduce my heating and cooling loads, and how much that will affect what I need. Not sure how to estimate that without getting someone to do a blower door test.

Also, should I look into replacing my ductwork upstairs? I've thought about getting them sealed or doing it myself, but maybe ductboard is bad enough to completely replace?

Just like with insulation, replacing ductwork means opening up walls, and that's a pretty significant project to undertake. The attic insulation, and overall air sealing are by far the lowest hanging fruits, followed by replacing the A/C units given their age. You can always go back and start replacing ductboard (especially if it's deteriorating), same with deferring insulation in the walls.

treefly

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Re: Help with HVAC Options
« Reply #5 on: January 20, 2023, 11:32:47 AM »

On the contrary, you would actually primarily rely on the heat pumps for heating in all but the coldest temperatures, usually when the COP drops below 2-2.5 depending on the overall performance of the heat pumps you'd buy.

This assumes that your electrical rates aren't absurdly high but consider that in many areas, heat pumps are the primary heating system being installed in new residential construction.


Sorry, I mean having them take over the entire heating load whenever the furnaces break. For reference, I paid $1.35/therm, and $0.122/kwh this past year, with 4500 kwh of cooling, and 1000 therms of gas.

chemistk

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Re: Help with HVAC Options
« Reply #6 on: January 20, 2023, 01:30:04 PM »

On the contrary, you would actually primarily rely on the heat pumps for heating in all but the coldest temperatures, usually when the COP drops below 2-2.5 depending on the overall performance of the heat pumps you'd buy.

This assumes that your electrical rates aren't absurdly high but consider that in many areas, heat pumps are the primary heating system being installed in new residential construction.


Sorry, I mean having them take over the entire heating load whenever the furnaces break. For reference, I paid $1.35/therm, and $0.122/kwh this past year, with 4500 kwh of cooling, and 1000 therms of gas.

This is also definitely possible. It would be something to factor in, though, as most heat pumps do have some sort of emergency heat source that's leveraged if the temperatures fall too low past the COP. If you had a cold snap for a couple days in the teen's or lower, and no backup, you'd probably only be able to keep the house at 65ish or lower.

But by relying on them as primary sources of heat, you could easily get another couple decades out of our existing furnace.

The cost differential is hard to pencil out without first knowing what system you would settle on.

SweatingInAR

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Re: Help with HVAC Options
« Reply #7 on: January 20, 2023, 03:33:55 PM »
You should borrow, rent, or buy a thermal camera and walk around your house to see where the biggest leaks are. You might find a wall that was never insulated! The stairwell to the loft in my house was uninsulated on one side, so it only had drywall separating it from attic air.

It could also be useful in the attic to check for under-insulated and leaky ductwork.

Option 3:
Change to 19 Seer 3 ton, 2 stage heat pump(York YZT) paired with 96% furnace: $22,453
   For this one, I could get the 30% tax break up to $2k, so it's really $20k.

I would not proactively replace both units. I doubt that they will magically cut your utility spending in half. Maybe replace one?
Do you have smart thermostats that could tell you which unit runs more? This would let you prioritize one unit over the other.
Do you have to change both units at the same time to take advantage of this tax break, or could you do one in 2023 and the other when it fails?
Alternatively, could you upgrade one to 19 SEER and the other to 16 for the rebate?

I noticed a trend in my coworker's multi-AC homes. I don't have much data, but regardless... I noticed that homes with 2 identical units would have them fail in the same manner in short succession. As a result, I am of the opinion that someone would be better off with two different-manufacturer AC units so that they don't fail at the same time in the same way.

treefly

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Re: Help with HVAC Options
« Reply #8 on: January 23, 2023, 09:38:25 AM »
@SweatingInAR Unfortunately the units are too old to hook up to smart thermostats, that would be one advantage of replacing them. Interesting idea to replace them separately though, I will look into it. I think the leaks for now are obvious enough that I don't need a thermal camera, but that is a good idea for after I get the gaping holes sealed ¯\_(ツ)_/¯

index

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Re: Help with HVAC Options
« Reply #9 on: January 23, 2023, 10:19:51 AM »
@SweatingInAR Unfortunately the units are too old to hook up to smart thermostats, that would be one advantage of replacing them. Interesting idea to replace them separately though, I will look into it. I think the leaks for now are obvious enough that I don't need a thermal camera, but that is a good idea for after I get the gaping holes sealed ¯\_(ツ)_/¯

You can wire a smart thermostat to an old furnace or ac. I had an Ecobee on a 1976 furnace/ac. Yes, the 40 year old ac was still kicking!

I would focus on your insulation first and foremost. I would pay an insulation contractor to air seal and blow in new insulation and spray or flash and bat your basement rim joists. Probably under $3k for all that work. You can DIY but you will pay 2/3rds of the pro install price just for materials and will not do nearly as good of a job. If you have any problem windows, order Larson gold or silver low-e storms for those windows.

The heating and cooling loads are insane for your house. 160k btu worth of furnaces are 2x what you should need heat wise and 6 tons of A/C for 3500 sf is probably 2 tons high as well. For reference, my home is 2400 sf, 110 years old with original windows and 2 climate zones north of you and we use a 70k btu 2 stage furnace and 3 tons of AC (and the ac is oversized).

I would spend $3k on getting your place insulated, replace both A/Cs with 2 ton heat pumps and keep the furnace in the basement. Those prices seem high if they are not replacing a lot of duct work. You should be getting top of the line trane/mitsubishi equipment for those prices.   

mizzourah2006

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Re: Help with HVAC Options
« Reply #10 on: January 24, 2023, 10:09:20 AM »
I'm currently in this situation too. My system is 19 years old and I just paid $1k to get the control board replaced. The technician said my HVAC is limping along and could go out at any point.

I'd love everyone's opinions on what to do. Current setup is a traditional HVAC with electric AC and gas furnace. We live in the Bentonville, AR area so winters are typically mild, with a few weeks of nights dipping into the 20s or teens and the occasional couple of days where it might get colder, but overall typical January and February's are lows in the low 30s and highs in the mid 40s to 50s. Summers can get hot.

We are also pretty flexible on temperatures. In the summers we usually let it get to 78-80 in the day and then turn it down to 75ish at night. In the winters we usually let it get to 60/61 during the day and turn it up to 64 at night. For this reason I'm wondering if just having a heat pump system may be enough and we may be able to get by without a dual fuel system. Also open to the idea that a heat pump isn't even the right option and that it's overhyped, but from what I'm seeing it seems like a good option for us.

Monthly average temps: https://weatherspark.com/y/9740/Average-Weather-in-Bentonville-Arkansas-United-States-Year-Round


FLBiker

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Re: Help with HVAC Options
« Reply #11 on: January 24, 2023, 10:12:50 AM »
I'm currently in this situation too. My system is 19 years old and I just paid $1k to get the control board replaced. The technician said my HVAC is limping along and could go out at any point.

I'd love everyone's opinions on what to do. Current setup is a traditional HVAC with electric AC and gas furnace. We live in the Bentonville, AR area so winters are typically mild, with a few weeks of nights dipping into the 20s or teens and the occasional couple of days where it might get colder, but overall typical January and February's are lows in the low 30s and highs in the mid 40s to 50s. Summers can get hot.

We are also pretty flexible on temperatures. In the summers we usually let it get to 78-80 in the day and then turn it down to 75ish at night. In the winters we usually let it get to 60/61 during the day and turn it up to 64 at night. For this reason I'm wondering if just having a heat pump system may be enough and we may be able to get by without a dual fuel system. Also open to the idea that a heat pump isn't even the right option and that it's overhyped, but from what I'm seeing it seems like a good option for us.

Monthly average temps: https://weatherspark.com/y/9740/Average-Weather-in-Bentonville-Arkansas-United-States-Year-Round

I'm not an expert on HVAC, but I think a heatpump would be a great option in that climate.  I'm in Nova Scotia, and many folks up here mostly use heatpumps, with supplemental systems for the coldest nights (-20C or so) which would be much colder than anything you'd see.  I've been very happy with hours -- the maintenance is very simple, it's quiet and has been reliable.  We're thinking about adding one downstairs as well (we currently use a pellet stove down there as our primary heat).

chemistk

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Re: Help with HVAC Options
« Reply #12 on: January 24, 2023, 10:28:54 AM »
I would spend $3k on getting your place insulated, replace both A/Cs with 2 ton heat pumps and keep the furnace in the basement. Those prices seem high if they are not replacing a lot of duct work. You should be getting top of the line trane/mitsubishi equipment for those prices.

Just want to point out that HVAC prices vary wildly region to region. Last year, our 3ton Carrier system with new air handler was just a hair under $10k, but in the Midwest where my brother works in HVAC distribution, the all in cost would have been closer to $7-8k.

chemistk

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Re: Help with HVAC Options
« Reply #13 on: January 24, 2023, 10:34:37 AM »
I'm currently in this situation too. My system is 19 years old and I just paid $1k to get the control board replaced. The technician said my HVAC is limping along and could go out at any point.

I'd love everyone's opinions on what to do. Current setup is a traditional HVAC with electric AC and gas furnace. We live in the Bentonville, AR area so winters are typically mild, with a few weeks of nights dipping into the 20s or teens and the occasional couple of days where it might get colder, but overall typical January and February's are lows in the low 30s and highs in the mid 40s to 50s. Summers can get hot.

We are also pretty flexible on temperatures. In the summers we usually let it get to 78-80 in the day and then turn it down to 75ish at night. In the winters we usually let it get to 60/61 during the day and turn it up to 64 at night. For this reason I'm wondering if just having a heat pump system may be enough and we may be able to get by without a dual fuel system. Also open to the idea that a heat pump isn't even the right option and that it's overhyped, but from what I'm seeing it seems like a good option for us.

Monthly average temps: https://weatherspark.com/y/9740/Average-Weather-in-Bentonville-Arkansas-United-States-Year-Round

All my sentiments in this thread apply to your situation. Heat pumps are the future for most folks in Zone 5 and South, so you're not hopping on some hype trend. Eventually, we will move away from NG and other residential combustion heat sources for climates with milder winters. It will take time but that's where things are going right now - NG burned in a power plant and supplied as electricity to residential heat pumps much more of an efficient use of that fuel compared to NG plumbed directly to homes.

I would strongly consider replacing your system before it completely dies. You'll immediately recoup some of the costs in year round efficiency, and by leaning on the heat pump as your primary heat source, you would have the option to keep you NG furnace much longer while using it a lot less, or just tear it out completely have have heat strips installed as backup.


mizzourah2006

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Re: Help with HVAC Options
« Reply #14 on: January 24, 2023, 10:56:57 AM »
All my sentiments in this thread apply to your situation. Heat pumps are the future for most folks in Zone 5 and South, so you're not hopping on some hype trend. Eventually, we will move away from NG and other residential combustion heat sources for climates with milder winters. It will take time but that's where things are going right now - NG burned in a power plant and supplied as electricity to residential heat pumps much more of an efficient use of that fuel compared to NG plumbed directly to homes.

I would strongly consider replacing your system before it completely dies. You'll immediately recoup some of the costs in year round efficiency, and by leaning on the heat pump as your primary heat source, you would have the option to keep you NG furnace much longer while using it a lot less, or just tear it out completely have have heat strips installed as backup.

This is very helpful thanks. The technician said something about the coils in my furnace being very rusted and the blower motor was running at 10 amps, which is very high. The way he described it was that the furnace wouldn't make it much longer either and was already really inefficient. I've read that the heat strips are pretty inefficient as well, but given that we aren't trying to keep our house at 72 when it's 15 outside do you think that would be sufficient?

chemistk

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Re: Help with HVAC Options
« Reply #15 on: January 24, 2023, 11:12:41 AM »
All my sentiments in this thread apply to your situation. Heat pumps are the future for most folks in Zone 5 and South, so you're not hopping on some hype trend. Eventually, we will move away from NG and other residential combustion heat sources for climates with milder winters. It will take time but that's where things are going right now - NG burned in a power plant and supplied as electricity to residential heat pumps much more of an efficient use of that fuel compared to NG plumbed directly to homes.

I would strongly consider replacing your system before it completely dies. You'll immediately recoup some of the costs in year round efficiency, and by leaning on the heat pump as your primary heat source, you would have the option to keep you NG furnace much longer while using it a lot less, or just tear it out completely have have heat strips installed as backup.

This is very helpful thanks. The technician said something about the coils in my furnace being very rusted and the blower motor was running at 10 amps, which is very high. The way he described it was that the furnace wouldn't make it much longer either and was already really inefficient. I've read that the heat strips are pretty inefficient as well, but given that we aren't trying to keep our house at 72 when it's 15 outside do you think that would be sufficient?

Ours is more or less an entry level system (albeit from a more reputable manufacturer). Heat strips are inefficient relative to the heat pump, but are still an efficient use of energy (heat pump is >200% efficient where heat strips are about 100% efficient) . The number of times you'll leverage the heat strips will vary, based on the performance of the system you have, the age of your house, and the R-value of your insulation.

Over the course of this entire month of January, where temps for us have been between 35-50 during the day and 25-45 overnight, our heat strips have not been used. We keep the house at 65, and it's an older house with an underinsulated attic. When the exterior temperature is >40F, the air from the heat pump is hot enough that you wouldn't really know it's not natural gas.

I'd get to replacing your system this year. Rusted coils and stuffy air handlers can put you at risk for elevated levels of CO and other combustion byproducts in your home. 

mizzourah2006

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Re: Help with HVAC Options
« Reply #16 on: January 24, 2023, 11:18:24 AM »
Ours is more or less an entry level system (albeit from a more reputable manufacturer). Heat strips are inefficient relative to the heat pump, but are still an efficient use of energy (heat pump is >200% efficient where heat strips are about 100% efficient) . The number of times you'll leverage the heat strips will vary, based on the performance of the system you have, the age of your house, and the R-value of your insulation.

Over the course of this entire month of January, where temps for us have been between 35-50 during the day and 25-45 overnight, our heat strips have not been used. We keep the house at 65, and it's an older house with an underinsulated attic. When the exterior temperature is >40F, the air from the heat pump is hot enough that you wouldn't really know it's not natural gas.

I'd get to replacing your system this year. Rusted coils and stuffy air handlers can put you at risk for elevated levels of CO and other combustion byproducts in your home.

Yeah we knew it was coming. I have the company that just serviced the control panel coming out Friday. Then I'll probably get a few more quotes and make a decision in March/April. Our home was built in 2004, so it's the original HVAC. Your input has been extremely helpful. I don't know much about this type of stuff and I've never had to replace a system as this is the first home I've owned.

treefly

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Re: Help with HVAC Options
« Reply #17 on: January 24, 2023, 11:39:09 AM »
@SweatingInAR Unfortunately the units are too old to hook up to smart thermostats, that would be one advantage of replacing them. Interesting idea to replace them separately though, I will look into it. I think the leaks for now are obvious enough that I don't need a thermal camera, but that is a good idea for after I get the gaping holes sealed ¯\_(ツ)_/¯

You can wire a smart thermostat to an old furnace or ac. I had an Ecobee on a 1976 furnace/ac. Yes, the 40 year old ac was still kicking!

I would focus on your insulation first and foremost. I would pay an insulation contractor to air seal and blow in new insulation and spray or flash and bat your basement rim joists. Probably under $3k for all that work. You can DIY but you will pay 2/3rds of the pro install price just for materials and will not do nearly as good of a job. If you have any problem windows, order Larson gold or silver low-e storms for those windows.

The heating and cooling loads are insane for your house. 160k btu worth of furnaces are 2x what you should need heat wise and 6 tons of A/C for 3500 sf is probably 2 tons high as well. For reference, my home is 2400 sf, 110 years old with original windows and 2 climate zones north of you and we use a 70k btu 2 stage furnace and 3 tons of AC (and the ac is oversized).

I would spend $3k on getting your place insulated, replace both A/Cs with 2 ton heat pumps and keep the furnace in the basement. Those prices seem high if they are not replacing a lot of duct work. You should be getting top of the line trane/mitsubishi equipment for those prices.   

There was something about the lack of grounding wire which prevented the technician from installing a google nest, I'll look into it further. I have storms on the windows, but the current issue is that they're all super old and have very little sealing around them. There are lots of efficiency projects to be done. To optimize taxes, I would do windows, insulation, electrical, furnace, AC, and water heater in separate years, $1,200 each year. But there is always the risk of over-optimizing for taxes and not for real life.

lutorm

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Re: Help with HVAC Options
« Reply #18 on: January 24, 2023, 12:08:47 PM »
All my sentiments in this thread apply to your situation. Heat pumps are the future for most folks in Zone 5 and South, so you're not hopping on some hype trend. Eventually, we will move away from NG and other residential combustion heat sources for climates with milder winters. It will take time but that's where things are going right now - NG burned in a power plant and supplied as electricity to residential heat pumps much more of an efficient use of that fuel compared to NG plumbed directly to homes.
I'm with chemistk here. Even if it appears right now that it would be cheaper to continue to rely on burning fossil fuels, the writing is clearly on the wall and I don't think assuming that this state will continue is prudent. This is regardless of what you think about the urgency of climate change.

My parents were in a similar, but opposite situation. They built a house in northern Sweden in 1976 and when looking at heat sources they were advised that, electricity being so cheap, it was a no brainer to just install direct electric heat. They ended up paying for that choice for the next 45 years because, guess what, electricity did not stay cheap and when you have direct electric it's extremely difficult to change to another heat source. If they had gone with what appeared, at that time, to be a slightly more expensive but much more flexible option and installed hydronic heat, they could have switched heat source at will because you can heat water with pretty much anything.

Air-carried heat used by so many US homes isn't nearly as bad since you can change the heat source without changing the ductwork, though, so I guess it's much less of a lock-in situation.

Jon Bon

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Re: Help with HVAC Options
« Reply #19 on: January 24, 2023, 08:00:58 PM »
As the others have said insulate.

Your utilities could be drastically cut with a few hundred pounds of chopped up newspaper.

Your furnace is fine, you live in South Carolina right? I mean how much does it even get used. Replacing your furnace with a slightly more efficient model would be wasteful.

I would get a few more bids on heat pumps, that feels like a crazy high number. Remember you do NOT want the company that has an office staff, a fleet of matching work trucks and slick marketing. You do want the guy that answers own phone and drives a beat up van and has enough work to not need to try and sell you a $23,000 heat pump system.




mizzourah2006

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Re: Help with HVAC Options
« Reply #20 on: January 30, 2023, 09:59:31 AM »
I got my first quote back.

Is there a huge benefit to two stage vs. one stage? It obviously seems beneficial from an efficiency standpoint, but how much?

I got a quote for the following:

1. Lennox ML17XC1 Heat Pump duel fuel system (single stage) for $11,630 after taxes
2. Trane XL17i Heat Pump duel fuel system (two stage) for $17,904 after taxes
3. Trane XV18 Heat Pump duel fuel system (750 stages) $19,403 after taxes.


Obviously I get how 2 and 3 are better and more efficient, but for $8k it doesn't seem completely worth it.

I have another company coming out on Thursday to give me a quote as well, and I'll probably also get a third quote, but right now I'm leaning towards the Lennox, but I'd love to hear thoughts on if I should consider the Trane. It almost seems like the XV18 for $1.5k more would be the one to go with if I'm jumping all the way up there for the Trane system.

chemistk

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Re: Help with HVAC Options
« Reply #21 on: January 30, 2023, 10:10:54 AM »
When were were going through these options last year, we were told that the 2 stage is more energy efficient but not by a large magnitude. I certainly don't think it justifies half the cost of an entire new system.

mizzourah2006

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Re: Help with HVAC Options
« Reply #22 on: February 03, 2023, 08:52:04 AM »
I got my second quote. Basically the same prices as the first company within a couple hundred dollars. I did ask if any of them qualified for the $2k federal rebate and the second salesmen said only the $22k system qualifies. I'm strongly leaning towards the $11.5k single stage dual fuel system. I could see how a variable stage system saves a lot of money if your house is very large and if they are very particular about consistent temperatures (i.e. want it to be 70-72 year round), but our house is only 2.2k sq ft and right now with a 20 year old 10 SEER (probably running about 6 SEER right now) we are only paying about $200/month on average between gas and electricity, with lows probably around $130s and highs, like this month around $300. Also, we are fine with it running at 60-64 in the winter and 76-80 in the summer, so we are pretty flexible with the exterior temperature.

FINate

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Re: Help with HVAC Options
« Reply #23 on: February 03, 2023, 09:44:09 AM »
What are the winter lows in your climate? Climate data for Spartanburg, for example, show average lows of 30 and an average daily temperature of around 40. Unless you're in the mountains or a micro climate where things are much colder, I wouldn't hesitate going all in on heat pumps. Modern heat pumps should perform well even if you have a few hours overnight that get into the 20s. Sealing and insulating will make this even more of a non-issue. Many systems include resistive heat backup in case temps drop too low, which is expensive but not a problem if this is a rare occurrence.

Since you're in the process of getting quotes, I would also get a quote from someone that specializes in heat pumps.

index

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Re: Help with HVAC Options
« Reply #24 on: February 03, 2023, 12:24:39 PM »
@SweatingInAR Unfortunately the units are too old to hook up to smart thermostats, that would be one advantage of replacing them. Interesting idea to replace them separately though, I will look into it. I think the leaks for now are obvious enough that I don't need a thermal camera, but that is a good idea for after I get the gaping holes sealed ¯\_(ツ)_/¯

You can wire a smart thermostat to an old furnace or ac. I had an Ecobee on a 1976 furnace/ac. Yes, the 40 year old ac was still kicking!

I would focus on your insulation first and foremost. I would pay an insulation contractor to air seal and blow in new insulation and spray or flash and bat your basement rim joists. Probably under $3k for all that work. You can DIY but you will pay 2/3rds of the pro install price just for materials and will not do nearly as good of a job. If you have any problem windows, order Larson gold or silver low-e storms for those windows.

The heating and cooling loads are insane for your house. 160k btu worth of furnaces are 2x what you should need heat wise and 6 tons of A/C for 3500 sf is probably 2 tons high as well. For reference, my home is 2400 sf, 110 years old with original windows and 2 climate zones north of you and we use a 70k btu 2 stage furnace and 3 tons of AC (and the ac is oversized).

I would spend $3k on getting your place insulated, replace both A/Cs with 2 ton heat pumps and keep the furnace in the basement. Those prices seem high if they are not replacing a lot of duct work. You should be getting top of the line trane/mitsubishi equipment for those prices.   

There was something about the lack of grounding wire which prevented the technician from installing a google nest, I'll look into it further. I have storms on the windows, but the current issue is that they're all super old and have very little sealing around them. There are lots of efficiency projects to be done. To optimize taxes, I would do windows, insulation, electrical, furnace, AC, and water heater in separate years, $1,200 each year. But there is always the risk of over-optimizing for taxes and not for real life.

Ecobee has a little device that allows installation without a C-wire.


index

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Re: Help with HVAC Options
« Reply #25 on: February 03, 2023, 12:33:28 PM »
I got my first quote back.

Is there a huge benefit to two stage vs. one stage? It obviously seems beneficial from an efficiency standpoint, but how much?

I got a quote for the following:

1. Lennox ML17XC1 Heat Pump duel fuel system (single stage) for $11,630 after taxes
2. Trane XL17i Heat Pump duel fuel system (two stage) for $17,904 after taxes
3. Trane XV18 Heat Pump duel fuel system (750 stages) $19,403 after taxes.


Obviously I get how 2 and 3 are better and more efficient, but for $8k it doesn't seem completely worth it.

I have another company coming out on Thursday to give me a quote as well, and I'll probably also get a third quote, but right now I'm leaning towards the Lennox, but I'd love to hear thoughts on if I should consider the Trane. It almost seems like the XV18 for $1.5k more would be the one to go with if I'm jumping all the way up there for the Trane system.


I would keep looking for quotes from smaller HVAC companies. The low end unit you are looking at is about $4k worth of equipment (depending on size). I priced out a Trane XV20i which is better than the high end units you were quoted for $8400. This is not installed. But you are paying 8k-10k for a day of work... 

mizzourah2006

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Re: Help with HVAC Options
« Reply #26 on: February 03, 2023, 12:45:38 PM »
I got my first quote back.

Is there a huge benefit to two stage vs. one stage? It obviously seems beneficial from an efficiency standpoint, but how much?

I got a quote for the following:

1. Lennox ML17XC1 Heat Pump duel fuel system (single stage) for $11,630 after taxes
2. Trane XL17i Heat Pump duel fuel system (two stage) for $17,904 after taxes
3. Trane XV18 Heat Pump duel fuel system (750 stages) $19,403 after taxes.


Obviously I get how 2 and 3 are better and more efficient, but for $8k it doesn't seem completely worth it.

I have another company coming out on Thursday to give me a quote as well, and I'll probably also get a third quote, but right now I'm leaning towards the Lennox, but I'd love to hear thoughts on if I should consider the Trane. It almost seems like the XV18 for $1.5k more would be the one to go with if I'm jumping all the way up there for the Trane system.


I would keep looking for quotes from smaller HVAC companies. The low end unit you are looking at is about $4k worth of equipment (depending on size). I priced out a Trane XV20i which is better than the high end units you were quoted for $8400. This is not installed. But you are paying 8k-10k for a day of work...

Yeah, that seems accurate. I see the following breakdown:

Lennox ML17XP1: $3,800
Cooling Coil: $1,350
Furnace: $1,590
Misc (Refrigerant lines, thermostat, flue vent, new whips, gas piping, and permits): $1,195
Labor: $2,300
Taxes: ~$1,000
Total: ~$11,300