Talk to me about heat pumps vs. convential central air conditioners

[Primalzer]

So I got caught up in reading and researching central AC units...my unit is of unknown age, and while it still works, I have no idea for how long, and I'm sure it's fairly inefficient (house was built in 1981, and it may be original to the house....) While researching central air units, I ran into information and recommendations to move over to heat pumps. Currently I have a gas furnace and central AC integrated into the same fan housing (that's common, right?) Now I've been told the furnace is around 10 years old, and probably in need of replacement within the next 5 years or so. So does anyone have experience with heat pumps? Are they inefficient for our area because of the extreme hot and cold we have? If I do go with one, would I need a supplemental little furnace? Also, anyone have any experience with geothermal heat pumps? I know the cost to install one of those units would be astronomical and a bit outrageous for a house with only 1350 SF...but the cost savings in energy and the fact that geothermal lasts basically forever is hard to pass up, especially if you want to stay in the same spot for a long time...

Thanks guys.

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[FESTER665]

I'm going to start looking into all this stuff soon as well. I'm thinking I'll get another year or two out of my furnace and central AC unit, I was toying with the idea of doing one of those Mitsubishi units where there's a unit in every room so each room is it's own "zone" in the house, then I would have the condenser outside for all of those. That would free up the close where the furnace is now, and I wouldn't have to hack up the slab to run a drain there for condensate like I would have to if I went with a new high efficiency unit.

 

[OffshoreDrilling]

buy a regular AC unit

/thread.

heat pumps are useful in warmer climates where you wouldn't have a full furnace, just an air handler. Extremely uncommon in this area.

 

[OffshoreDrilling]

I'm going to start looking into all this stuff soon as well. I'm thinking I'll get another year or two out of my furnace and central AC unit, I was toying with the idea of doing one of those Mitsubishi units where there's a unit in every room so each room is it's own "zone" in the house, then I would have the condenser outside for all of those. That would free up the close where the furnace is now, and I wouldn't have to hack up the slab to run a drain there for condensate like I would have to if I went with a new high efficiency unit.

little giant pump. no trenching necessary.

Still need a furnace for heat unless you've got a boiler and radiant floors/convectors

 

[OffshoreDrilling]

The way a heat pump works is essentially running your AC backwards. There is a reversing valve in the unit that changes the refrigerant flow direction. Your condenser is now inside and the evaporator is outside. There isn't much heat energy in the outside air at 10*. It would never keep up with hearing needs in extreme temperatures.

Now a ground source heat pump could be doable. You just drill a few wells in the ground a couple hundred feet deep and push some water lines down there. Then you have a pump circulating water through those lines that feed your heat pump heat exchanger.

 

[Primalzer]

Now a ground source heat pump could be doable. You just drill a few wells in the ground a couple hundred feet deep and push some water lines down there. Then you have a pump circulating water through those lines that feed your heat pump heat exchanger.

As I understand it, that's what they call geothermal...have to imagine it's ridiculously expensive to drill those holes...

 

[Gone_2022]

A furnace at 10 years old should not be at the end of its life. Especially if it was ever maintained or serviced. My recommendation would be to have a trusted service tech out to the house to evaluate the condition of the system. Sometimes a good cleaning and tune up is all that's needed. Have he or she provide you an estimate on replacement. It's not cheap so I would make sure it's worth it

If the house was built in 1981 and your furnace is 10'years old I would assume your outside AC unit is around the same. If it was original it would be 35 years old which I highly highly doubt.

 

[FESTER665]

little giant pump. no trenching necessary.

Still need a furnace for heat unless you've got a boiler and radiant floors/convectors

I have one of those now, just not a fan of it pumping up and out of the house for some reason. I was just thinking ahead to when I redid the kitchen (the furnace is technically along the wet wall of the kitchen and bathroom) I would just jackhammer over to it and add a drain to make less to go wrong as much as possible.

Those Mitsubishi wall units do both. They also have units I can ceiling mount as well if memory serves.

Kinda like this but different brand:

I'm sure I'll still end up just doing a furnace and A/C unit again, just a high efficiency version. Just was thinking of ways to gain square footage in the house. Then I could use the old closet from the Furnace as a stackable washer and dryer, and toss a tankless hot water heater in there and turn what was a tiny laundry room into a walk in closet for the master bedroom.

See I think of all these things I would like to do, then remember it's a 915 square foot ranch on a slab in Streamwood so why bother.

 

[OffshoreDrilling]

tankless water heaters are another waste of money, just not as reliable. high efficiency tank.

 

[OffshoreDrilling]

I have one of those now, just not a fan of it pumping up and out of the house for some reason. I was just thinking ahead to when I redid the kitchen (the furnace is technically along the wet wall of the kitchen and bathroom) I would just jackhammer over to it and add a drain to make less to go wrong as much as possible.

Those Mitsubishi wall units do both. They also have units I can ceiling mount as well if memory serves.

Kinda like this but different brand:

I'm sure I'll still end up just doing a furnace and A/C unit again, just a high efficiency version. Just was thinking of ways to gain square footage in the house. Then I could use the old closet from the Furnace as a stackable washer and dryer, and toss a tankless hot water heater in there and turn what was a tiny laundry room into a walk in closet for the master bedroom.

See I think of all these things I would like to do, then remember it's a 915 square foot ranch on a slab in Streamwood so why bother.

mild climate winters only for those bud. there should be a map floating around somewhere of where a heat pump is a viable alternative to a furnace. good luck getting that repaired too. $$ plus way more complex than most residential guys ever get a chance to work on in their day to day travels. Too many hacks out there.

 

[FESTER665]

tankless water heaters are another waste of money, just not as reliable. high efficiency tank.

That's my biggest hangup, I'm not even that worried about the efficiency, I would be doing it just to try to save square footage honestly. My gas bill is next to nothing all summer, but goes up quite a bit in winter because I need to pack more insulation in the attic. I've been slowly re-doing bedrooms in the house and doing them in closed cell foam which has helped a ton already, just need to get the attic once I get the roof replaced.

Fucking stupid houses.

 

[FESTER665]

mild climate winters only for those bud. there should be a map floating around somewhere of where a heat pump is a viable alternative to a furnace. good luck getting that repaired too. $$ plus way more complex than most residential guys ever get a chance to work on in their day to day travels. Too many hacks out there.

We're not mild winters now? All I hear about is global warming....

 

[OffshoreDrilling]

good luck selling the place with only a heat pump.

you'll have no problem after all your pipes freeze and your whole house needs to be remodeled from water damage

 

[stock-t-bird]

I sell the Mitsu's at work..great product for room additions & hot upstairs bedrooms etc..the Mitsu's are useless in the Chicago cold winter..at about 11 degrees they lose all capacity and you freeze your ass off.

Not really designed for whole house usage.

 

[FESTER665]

good luck selling the place with only a heat pump.

you'll have no problem after all your pipes freeze and your whole house needs to be remodeled from water damage

You're killing me today... Just laughing at the desk like a nutcase...

I just saw someone was quoted 23k to have that system installed on the Home Depot Q&A.... Holy hell.... Although I'm sure I would need to jump up to a 200A service to have those things all over the place.

Way to ruin my hopes and dreams!

 

[FESTER665]

Not really designed for whole house usage.

Tell those jerks to fix their website.

 

[stock-t-bird]

throw some snow & minus degree temps in that pic...you will see icicles in that house

 

[Primalzer]

A furnace at 10 years old should not be at the end of its life. Especially if it was ever maintained or serviced. My recommendation would be to have a trusted service tech out to the house to evaluate the condition of the system. Sometimes a good cleaning and tune up is all that's needed. Have he or she provide you an estimate on replacement. It's not cheap so I would make sure it's worth it

If the house was built in 1981 and your furnace is 10'years old I would assume your outside AC unit is around the same. If it was original it would be 35 years old which I highly highly doubt.

Went back to my initial purchase inspection...looks like I was wrong, and the AC compressor looks to be 16 years old (manufactured in 2000) and the furnace is 13 years old (manufactured in 2003). So I really should be a bit better off than I initially thought. The AC unit is getting up there in years, and as a 2-ton, may be a bit undersized for the house (1350 SF), but seems not egregiously so, and decently cools down the house.

 

[Gone_2022]

Went back to my initial purchase inspection...looks like I was wrong, and the AC compressor looks to be 16 years old (manufactured in 2000) and the furnace is 13 years old (manufactured in 2003). So I really should be a bit better off than I initially thought. The AC unit is getting up there in years, and as a 2-ton, may be a bit undersized for the house (1350 SF), but seems not egregiously so, and decently cools down the house.

I would assume that size is fine, both the furnace and outside unit need to operate together correctly and be sized correctly together. (Common sense).

I just looked at our home inspection. We just bought a home, 2700 square feet and our outside unit is 4 tons, inside furnace is 120,000 btu. So with yours being 2 tons that seems normal, double your square feet and you have our 4ton unit.

 

[Gone_2022]

Again I would really suggest looking around for someone trustworthy to come out and evaluate everything. When you go to buy new don't just throw bigger at the house, you may just waste electricity powering a larger unit you don't need. Make sure the HVAC tech sizes the home, and does not just give you an off the shelf unit thats on special or promo that month.

 

[Primalzer]

Again I would really suggest looking around for someone trustworthy to come out and evaluate everything. When you go to buy new don't just throw bigger at the house, you may just waste electricity powering a larger unit you don't need. Make sure the HVAC tech sizes the home, and does not just give you an off the shelf unit thats on special or promo that month.

Yeah, I have to find a good AC guy...my dad has a buddy that used to do it....but he hasn't talked to him in a long time....I know commercial guys, but I'm not sure how good they are with residential stuff

 

[Angus]

If the house was built in 1981 and your furnace is 10'years old I would assume your outside AC unit is around the same. If it was original it would be 35 years old which I highly highly doubt.

Found out last month my ac unit is from 1974. I knew it was old, but not that old.

 

[Gone_2022]

That's crazyness. Talk about inefficient lol. I mean I know they don't make them like they used to but damn

 

[OffshoreDrilling]

Went back to my initial purchase inspection...looks like I was wrong, and the AC compressor looks to be 16 years old (manufactured in 2000) and the furnace is 13 years old (manufactured in 2003). So I really should be a bit better off than I initially thought. The AC unit is getting up there in years, and as a 2-ton, may be a bit undersized for the house (1350 SF), but seems not egregiously so, and decently cools down the house.

if you're cooling down the house, especially with the warm summer we've had, it's likely sized correctly. You're better off with a unit that runs longer as it removes more humidity versus an oversized unit that short cycles. It will not only poorly remove humidity but it's going to decrease the life of the unit.

 

[Primalzer]

if you're cooling down the house, especially with the warm summer we've had, it's likely sized correctly. You're better off with a unit that runs longer as it removes more humidity versus an oversized unit that short cycles. It will not only poorly remove humidity but it's going to decrease the life of the unit.

I mean, how quickly should it be able to cool down the house? Right now, I keep it at 70 after 5 PM and all night until 7 AM, then it goes to 75 while I am at work. It usually takes 3 hours or so, at least, to cool it down to 70. Am I setting the disparity too high?