Author Topic: Replacing AC Condenser only vs evap coils + furnace?  (Read 549 times)

jeromedawg

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Replacing AC Condenser only vs evap coils + furnace?
« on: June 01, 2021, 05:16:04 PM »
Hey all,

We're about to go into escrow on a place where the seller disclosed that the AC condenser is out. When we walked through it looked pretty old and seems like it'll have to be swapped out. Stupidly, I didn't take a look at the furnace so it may be old too. A couple AC companies I've reached out to have said that if I'm changing the condenser out, there's a good chance I'll have to get the evap coils and furnace/blower changed out too. Is it a safe bet just to get all of this taken care of? Or does it sound like they're just trying to upsell?

AccidentialMustache

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #1 on: June 01, 2021, 09:29:07 PM »
How old (/banned) is the refrigerant it uses?

jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #2 on: June 01, 2021, 10:05:57 PM »
How old (/banned) is the refrigerant it uses?

We're not sure yet - planning to have a different no/less BS AC guy come out to check things out. I might have the other company come out just to give a second opinion but also don't want to waste too much time either. The AC is something I'll probably get done later in August

KYFIRE

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #3 on: June 02, 2021, 10:06:14 AM »
I went through similar issue last year when my heat pump compressor died, the new R410 gas can't be used on (most?) older systems primarily due to the evap coils.  My system was about 14 years old and I could have gotten fixed but between compressor and finding someone with the old gas (can't buy new anymore) it was nearly as much as a new system.  Unless it's only a few years old, I think you'll be in similar situation unfortunately.

yachi

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #4 on: June 02, 2021, 01:55:16 PM »
It's legitimate advice, not an upsell.  It's more likely than not that both units are the same age, and there have been lots of refrigerant changes (as other posters are noting).

Newer units are also more efficient, and can provide an offsetting energy savings that wouldn't be available with just a condenser replacement:
https://www.seerenergysavings.com/

jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #5 on: June 02, 2021, 09:16:27 PM »
Thanks for the feedback all.

Any specific recommendations on units - brand, size, etc? This is for a 1965sq ft home with two levels and attic space.


Is it worth considering getting mini-split system installed? Although, not sure how it works when you replace a Central AC/furnace with mini-split... do you typically want to remove all the duct work/venting and patch up the holes where the vents were?

Was reading up more and it seems another alternative is to go with a Multi Ducted Air Handler?
« Last Edit: June 02, 2021, 11:18:01 PM by jeromedawg »

norajean

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #6 on: June 02, 2021, 10:10:00 PM »
Further, if the coil sits atop the furnace and if the furnace is ancient, it might be prudent to replace it as well otherwise when it dies you pay labor to dismantle the coil. That way the new system is all the same vintage and matched - coil/condenser/furnace. Get itemized estimates for each component and labor, if you can.   On the the other hand, if is is a great old furnace they can run forever so consider keeping it.

KYFIRE

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #7 on: June 03, 2021, 08:12:01 AM »
Are you doing a separate AC and Furnace or heatpump? 

As far as brand the there's actually only really like 3 manufactures with a ton of brands.  Lennox, Trane, and Carrier (I think).  Anyhow, like a lot of things, a couple big corporations that buy other brands and then have different level "quality". 

From people I know who actually installed HVAC units, going with a mid to high tier is better but the critical detail is installation, especially vacuum and filling. 

I ended up going with a rebranded Armstrong heatpump (it's the lower version of Lennox, I have a looooong story about that and this dealer).  It's a top of the line 19 SEER unit with variable compressor and fan.  It was a much larger cost but so far saving about $50/month but the real benefit is it's far quieter, runs at capacity needed not just on or off like single stage units so much more consistent temps in the house, and of course more efficient.  I paid around $15.5k I think for that and then also added accessories.  Of course I would imagine a smaller sized one should be cheaper.  A regular single stage cheap one would have been around $8k.

jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #8 on: June 03, 2021, 08:22:16 AM »
Are you doing a separate AC and Furnace or heatpump? 

As far as brand the there's actually only really like 3 manufactures with a ton of brands.  Lennox, Trane, and Carrier (I think).  Anyhow, like a lot of things, a couple big corporations that buy other brands and then have different level "quality". 

From people I know who actually installed HVAC units, going with a mid to high tier is better but the critical detail is installation, especially vacuum and filling. 

I ended up going with a rebranded Armstrong heatpump (it's the lower version of Lennox, I have a looooong story about that and this dealer).  It's a top of the line 19 SEER unit with variable compressor and fan.  It was a much larger cost but so far saving about $50/month but the real benefit is it's far quieter, runs at capacity needed not just on or off like single stage units so much more consistent temps in the house, and of course more efficient.  I paid around $15.5k I think for that and then also added accessories.  Of course I would imagine a smaller sized one should be cheaper.  A regular single stage cheap one would have been around $8k.

That's what I'm not really sure on at this point. AFAIK the existing system is Condenser/Coil/Furnace. I don't know if there are better, more efficient options to choose from - would heat pump be an alternative to all that?

Good to know on the brands - we had a Trane at our last place and that thing was a tank. Lasted the 13 years I lived there and I think it had been installed several years before that.

I'll ask my AC guy about good mid-high tier brands and see if he recommends Lennox, Trane or Carrier.

How many tons is your unit btw?

KYFIRE

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #9 on: June 03, 2021, 08:50:11 AM »
I'm going to guess that in CA you guys really only have a furnace for the odd cold nights?  A heat pump is really an AC with the ability to reverse the gas flow so it can also be a heater so we don't have a separate furnace.  It works pretty well until below 40ish degrees and then the 22kw heaters kick in.  That's not too often so not too bad and I'm sure less of an issue in CA.

I looked mine up, it's a 5ton 20SEER actually.

jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #10 on: June 03, 2021, 09:53:33 AM »
I'm going to guess that in CA you guys really only have a furnace for the odd cold nights?  A heat pump is really an AC with the ability to reverse the gas flow so it can also be a heater so we don't have a separate furnace.  It works pretty well until below 40ish degrees and then the 22kw heaters kick in.  That's not too often so not too bad and I'm sure less of an issue in CA.

I looked mine up, it's a 5ton 20SEER actually.

Gas is also cheaper in SoCal whereas electricity pricing can get pretty bad. So I think that might be the other reason. But yea, we never use our furnaces as much as our ACs... well, maybe other people do but we definitely didn't haha. Heat pumps are fully electric right? So I think that could drive our electric costs up during the 'colder' months (ha ha)...unless we just avoid using heat all together. When you're used to 70F weather all year round, those 50F nights feel super cold hahahaha!

Are there other good alternatives? I've read about multi-position air handlers too, which *seems* to be a more compact/condensed version of a standard AC/furnace setup.

KYFIRE

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #11 on: June 03, 2021, 10:28:56 AM »
I'm not sure whether they're better or not for sure but I could see where they might be as can isolate by room/section.  Central air can do this by using zones (I had on old unit, thinking I'm going to add again on this one).  But I would also think installation would be a lot more since they'll have to route new lines vs likely re-using your existing line set. 


jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #12 on: June 03, 2021, 11:49:47 AM »
I'm not sure whether they're better or not for sure but I could see where they might be as can isolate by room/section.  Central air can do this by using zones (I had on old unit, thinking I'm going to add again on this one).  But I would also think installation would be a lot more since they'll have to route new lines vs likely re-using your existing line set.

Are you referring to heat pump or the multi-position air handler in terms of something better and isolating by room/section?

I didn't realize central air could do that but it makes sense but yea I wouldn't want to have the ducting all re-done at least at this point.

jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #13 on: June 03, 2021, 12:16:01 PM »
Thought about cases where a heat pump might make more sense and actually I think if you were to go solar (or already are solar) it would make a lot more sense since you can leverage the KWs generated from solar. I don't know if we're quite there at the moment - I've thought about adding solar panels to the roof and if we were to do that then maybe a heat pump would make better sense.


AccidentialMustache

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #14 on: June 04, 2021, 09:03:15 PM »
Modern heat pumps aren't that bad in terms of expensive. Calk and insulation if you have air turnover issues will do you more good long term than a "cheaper to run" ac/gas furnace.

Due to coil design (copper + aluminum, gotta [not] love it!) when we moved in our new house, it's system leaked to non-functional in the first year. It was air-source heat pump, we replaced it with another air-source heat pump (but with a coil which won't self-corrode).

Previous house has a ground-sourced heat pump that we put in. It was supposed to be cheaper than gas, but that was just as fracking was really getting going and tanking the price of gas. It ended up more expensive, but not that much more expensive across the year, overall than the old system. Also turning off the gas and saving the $20/mo connection fee pays for a lot of power.

Both cost more in the winter than the summer but the cost isn't that bad. I'm in the midwest and get far, far colder (occasional single digit Fahrenheit highs) than you will. Also more humid, because... the midwest.

jeromedawg

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Re: Replacing AC Condenser only vs evap coils + furnace?
« Reply #15 on: June 04, 2021, 11:02:12 PM »
Modern heat pumps aren't that bad in terms of expensive. Calk and insulation if you have air turnover issues will do you more good long term than a "cheaper to run" ac/gas furnace.

Due to coil design (copper + aluminum, gotta [not] love it!) when we moved in our new house, it's system leaked to non-functional in the first year. It was air-source heat pump, we replaced it with another air-source heat pump (but with a coil which won't self-corrode).

Previous house has a ground-sourced heat pump that we put in. It was supposed to be cheaper than gas, but that was just as fracking was really getting going and tanking the price of gas. It ended up more expensive, but not that much more expensive across the year, overall than the old system. Also turning off the gas and saving the $20/mo connection fee pays for a lot of power.

Both cost more in the winter than the summer but the cost isn't that bad. I'm in the midwest and get far, far colder (occasional single digit Fahrenheit highs) than you will. Also more humid, because... the midwest.

Here in SoCal electricity prices are pretty costly. My initial thoughts (with my limited knowledge of heat pumps) is that in this area you'd only really want to invest in something like that if you had the right "system efficiency" to provision for it, meaning a home that has a combination of good insulation (windows, etc) and also solar panels. Otherwise, I could see bills getting run up quite a bit. Maybe I'm completely wrong though - anyone here from SoCal who has a heat pump, begs to differ, and wants to share your thoughts and numbers?