Everything you didnt want to know about gas hot air furnances... and HVAC Quicksand

[samclem]

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So leaning to replace furnace and debating how high tech to go. Better efficiency and complexity or replace with like kind?
House was built in 1963 current unit installed in 1996 along with AC. We have no plans to move so may be here another 20 years.
Starting to get quotes.

Oh....northern PA, it was 7 degrees this morn but now up to 30 and sunny. And have two ventless log sets as backup heat.

AC: If is still working, I'd probably leave it alone. I'd imagine you run it for about 4 months of the year in N. PA, and it might last a long time. Given that use, it could be a long time before the greater efficiency paid for the replacement.


Furnace: Here's a site with some equipment options and prices, just to give you an idea. 80% furnaces are still sold, and (if they are allowed in your area) then they'll have the lowest installation costs since your existing flue can be used without modification and there's no need to run a condensate line. The newer 93%+ "condensing" units are more efficient so will save you money on natural gas, but they are more complex and are likely to be more trouble than an 80% unit. The condensing units are more popular than the 80% units, but do the math using your gas bill (and estimated future gas prices) to see if it is worth it to you.

 

[Bamaman]

Next time round, I'm getting rid of that Trane heat pump, and going to mini-split heat pumps in my lake house. It'll drop my utility bill in half--not having to heat ductwork. It'll take 2 complete units with 3 and 2 evaporator heads respectively.

 

[target2019]

So leaning to replace furnace and debating how high tech to go. Better efficiency and complexity or replace with like kind?
House was built in 1963 current unit installed in 1996 along with AC. We have no plans to move so may be here another 20 years.
Starting to get quotes.

We had two original systems from 1970's, and replaced both about 3-4 years ago.

• 2- R802VA100521MSA 100,000 Btu’s 80% Efficiency Two Stage with ECM Blower Motor, 10 year parts manufacture warranty, limited life time warranty on heat exchanger manufacture
• 2- RA1630AJ1NA 2½ Ton 16.0 Seer Condenser R410A Freon 10 year parts manufacture warranty
• 2- RCF3621MTAMCA Matching Cooling Coil

ECM is the key component in my opinion.

 

[RE2Boys]

AC: If is still working, I'd probably leave it alone. I'd imagine you run it for about 4 months of the year in N. PA, and it might last a long time. Given that use, it could be a long time before the greater efficiency paid for the replacement.


Furnace: Here's a site with some equipment options and prices, just to give you an idea. 80% furnaces are still sold, and (if they are allowed in your area) then they'll have the lowest installation costs since your existing flue can be used without modification and there's no need to run a condensate line. The newer 93%+ "condensing" units are more efficient so will save you money on natural gas, but they are more complex and are likely to be more trouble than an 80% unit. The condensing units are more popular than the 80% units, but do the math using your gas bill (and estimated future gas prices) to see if it is worth it to you.

Good notes to follow. In our area, some summers the A/C is needed only a few weeks a year, other summers can be a solid two months. And primarily to control humidity rather than cooling.

 

[Bamaman]

That house is possessed by demons. I would consider moving! Like to a lower COL area with a much better climate.

I lived in an ultra low cost of living area with a decent climate--at least until the rains started in August. We have not seen dirt since then. But thankfully my 7 year old granddaughter has never touched snow, either.

My upstairs has a relatively new natural gas furnace/air conditioning unit--replaced at 15 years old. My downstairs has a conventional heat pump installed horizontally in a closet 10' off the floor--strange configuration.

After getting one of those Cadillac priced utility bills, down comes the thermostat and off goes the downstairs heat pump. I just use a ceramic cube heater cut down to 750 watts, and it keeps my bedroom toasty.

Two things that scare me are replacing my roof and replacing that heat pump. But since my downstairs is one huge room and 2 bedrooms, it'll work well to replace it with two mini-split heat pumps that will be half the cost of that conventional heat pump.

I don't mind paying a reasonable profit for a quality job. But some of the prices I've seen on new HVAC units versus the units that can be bought on the internet have a wide variance--too much profit.

 

[samclem]

Next time round, I'm getting rid of that Trane heat pump, and going to mini-split heat pumps in my lake house. It'll drop my utility bill in half--not having to heat ductwork. It'll take 2 complete units with 3 and 2 evaporator heads respectively.

Where do your ducts go--under the lake? It would be a rare house with ducts that cause a 50% reduction in system efficiency.

 

[Koolau]

In our old place (on the frozen tundra of the midwest) we had 90+% eff furnace/AC units starting in early 80s. The units sat outside - meaning no flue through the roof. Heat transfer was "liquid" (absorbed the heat or cold and then pumped inside to the blower system.) They worked very well - until they don't. The house involved (which we still use most summers) is on its third such unit - so about 10 to 12 years and it's an expensive paper weight. I guess, as they used to say, "economy ain't cheap." YMMV