Gas and Oil Home Heating Furnaces - My Installer Recommends 80%, not 92% Efficiency on Furnace

I opted for a gas furnace with 92% efficiency rating but my installer said that 80% would be better in the long run (7-10 years down the road) with less maintainence costs and less problems. He said that in his experience, people with the higher efficient models (90% and up) were more prone to condensate related problems due to being more complex in design or a "different animal" vs the more simple, 80% rated model. He also said that being 12% more efficient is not that a big difference. This is coming from a man (installer) with 35+ years experience. He will be putting in a Goodman furnace.

We will be using the heater for only 3- 4 months out of the year out here in sunny southern California. What do you guys think?

He is making a reasonable point.

High efficiency furnaces make more sense in cold climates than in warm climates where heat is only needed for a brief part of the year.

Condensing furnaces are more complex and more expensive, and have a greater number of things that can go wrong.

That's not a big difference, but it's real in my experience.

In my town of Seattle, I do perfectly well with an old window air conditioner for the few days a year I operate it. It's cheap, low efficiency equipment, but the cheap and simple means a lot more to me than the efficiency of the equipment around here.

Same kind of issue with the seasons reversed.

I agree. In your area the payback on a 90+% efficient furnace along with the increased maintenance & possible (probable?) repair costs would, in my opinion, tip the scales in favor of the 80% unit.

I agree with Seattle, Grady and your installer.

We only recommend condensate furnaces for basement installations in my area.

I had the choice between a 80% and a 95% furnace after getting rid of a old 65% furnace with a questionable heat exchanger.

I chose a 80% unit because of the relatively low heating requirements (2 story 1600 sf townhouse with only two exterior walls (north and east), but a northern exposure with 6' sliding doors on both levels.

I have a gas furnace and a gas water heater. In the summer, my monthly gas bill is $16 (half usage and half minimums and fees). even in the coldest Minnesota weather, my total monthly gas bill has been $90 (only twice in 5 years) for heat, water heating and minimums.

The reason I chose an 80% was the installation cost and problems for the venting for the high efficiency, while the existing chimney venting could be used. It is also not as ugly as the high efficiency and has no cloud of vapors on a -20F night.

I have been very happy for two reasons. First, I got a very fast and quality installation from a reputable contractor (4 hours from start to final gas inspection). The second was getting a furnace with a variable speed fan that is quiet and efficient. I ended up with a much more comfortable home and you never really notice when the second stage burner kicks in unless you really listen. The second stage never runs unless during the morning start-up because we have a 8 degree set-back over night (it may have run once at -30F). The unit also seemed to increase the efficiency or performance of the old AC units that was retained.

Dick