Replacing a gas furnace and adding AC to a forced air heating system
May 26, 2011 12:52 PM   Subscribe

We have an oldish (~90 years or so) house with a gas furnace and forced air heating. We're thinking of replacing the furnace and adding an AC compressor for cooling. I'm looking for recommendations for specific furnaces and compressors (brands or models), especially ones that are long lasting and/or energy efficient. We'd also like to hear stories and or warnings about setting this up in an old house.

Not sure how old the ductwork is but it would be very, very difficult to make any changes to it, and I know certain systems may require upgrades to duct work.

We're replacing the furnace because it's at least 15-20 years old, is not a particularly good brand, and the home inspector told us that essentially once you factor in the labor cost of adding the compressor to the furnace it's worth it to just replace the furnace while we're at it.

I would be willing to sacrifice some energy efficiency for furnace longevity, since I figure the monetary and economic costs of replacing a furnace sooner would be greater than a small amount of inefficiency.

I keep spelling it furnance for some reason. I had to go through my post and delete at least have a dozen n's.
posted by Deathalicious to Home & Garden (7 answers total) 3 users marked this as a favorite
Best answer: For your "stories" file -- I would prioritise finding a furnace person you trust and who you enjoy dealing with. I have an old house and had a lot of furnace bother. First furnace broke; "Direct Energy" offered a nearly $1k repair, also offered an awful salesman who...oh, long story short, I found myself calling and e-mailing "Direct Energy" with a great deal of rage when awful salesman would not stop leaving me messages. It was a deeply unpleasant experience.

But, it lead me to my current furnace guy, who did the purported $1k repair for a bit over $200. Shop around. He warned me that the thing would die soon, and, next year, dead. I was happy to go to $200-repair guy's entry-level furnace; his best deal was way better than what I had been offered from DE, and also notably cheaper than Costco's offering, and two other local little HVAC firms'.

Some little teething troubles in the first new-furnace year were dealt with so well that I blither on to neighbours about how they totally want to call my furnace guy if they have furnace issues, while at the start of furnace trouble with the Direct Energy people I was tremendously stressed. If you can find a good person to hold your hand through your furnace transition phase, it makes a huge difference. (Persons west of Ottawa want to see Adrian at Reliable Heating)

I apologise for the long story with lack of brand recommendation -- I went with 'cheap,' 'so much more efficient than the old one that it scarcely matters if others are even better,' 'good warranty,' and I'm not even sure of the brand. But, yeah. You may see a lot of whomever you choose, you may see them at less than ideal hours of day, you will want to depend on a good response -- be picky. If a place acts like it's a chore to give you a quote, or a minor inquiry turns into a big sales hustle, I would not count on better service when it's urgently needed.
posted by kmennie at 2:08 PM on May 26, 2011

Best answer: I'll second what kmennie said, it is all about finding the right company. Find friends who have had work done, or people in the construction trades to get recommendations. Then call two or three out to give you recommendations and bids on the job.

Any reliable company will recommend reliable equipment.

That said, I just installed a Carrier ac/air handling unit, i'm happy with the equipment. And, although the job (due to odd factors in the house) took three or four return calls to get things exactly right, the company has been responsive, hasn't charged me an additional penny and has sent good people out.

It's all about the right company (did I say that before?).
posted by tomswift at 2:16 PM on May 26, 2011

Best answer: Not sure how old the ductwork is but it would be very, very difficult to make any changes to it, and I know certain systems may require upgrades to duct work.

If your current ductwork configuration has been working for you (e.g. sufficient airflow, etc.) it should be fine for adding AC, but it's a good idea to have all of it cleaned. Your furnace/AC installer might offer this as part of the upgrade process already. Make sure to get a few quotes and weight your decision in favor of locally owned companies than have an established history.
posted by amyms at 3:03 PM on May 26, 2011

that* have an established history
posted by amyms at 3:04 PM on May 26, 2011

Best answer: We just finished installing a compressor/coil to our forced hot air system. We have a good family friend who does HVAC and is extremely knowledgable. Per his recommendation, we ended up with a coil and condenser made by York. I asked him about other brands and he had nothing but great things to say about York stuff and strongly recommended we go with something by them.

Our system is new (~10 years) so I don't have much to offer in terms of older systems. We basically just added the coil above the furnace, installed the condenser, and ran the piping.

I don't have much besides that to add. It hasn't even been warm enough to warrant using it yet. :)

Good luck!
posted by Tu13es at 5:37 PM on May 26, 2011

Response by poster: I don't have much besides that to add. It hasn't even been warm enough to warrant using it yet. :)

Yeah, my wife is pregnant and the temperature was in the low 90s today, so the AC is sort of a higher priority now.
posted by Deathalicious at 8:24 PM on May 26, 2011

Response by poster: We survived the summer without AC. Turns out one real problem is we're probably going to have to install return vents. Not sure how we'll find the space for them in our already very cramped house.
posted by Deathalicious at 12:20 PM on October 28, 2011

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