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Gas, Forced-Air Furnace Replacement Query
QUESTION:Our residential HVAC maintenance company has recommended that we
replace our very old (20+ year) forced-air, gas furnace. We have used this
company for 12 years, without major problems, and I have no reason to
doubt the validity of their recommendation.
Their service technician suggested a mid-efficiency Lennox forced-air,
gas furnace (G20Q3/4 100) (AFUE 78%) and quoted a price of $1,900,
installed. This is for an 1,800 square foot, ranch style house. The
furnace comes with a 5 year parts warranty and they give 2 years on the
labor (20 years on the heat exchanger).
Are there any HVAC FAQs that I should read before entering into an
agreement with them? Any other "gottchas" that I should be aware of?
We're also considering adding an electrostatic air cleaner at the same
time. Any thoughts or suggestions on this?
ANSWER: Why are they recommending this? If the furnace has holes or cracks in
the
heat exchanger, then this should be done. If they just see an old unit
and think you should have a new one, think twice. If you are happy with
the way it heats and don't mind the heating bill, you may not need to
change.
Sounds like the technician sees some commission. I don't like the G20 personally. The 78% is misleading. Lennox got that
furnace
through some kind of loophole in the rating system to get it called 78%.
When
installed in the house, my guess is that it is more like 70% when one
factors
in all the air lost up the draft hood. Air that you paid to heat but
that
furnace isn't being rated considering all that lost heat. Without the
draft
inducer, it really isn't any more efficient than many standard furnaces.
I can
elaborate more if that isn't too clear. If you like the company and like
the
idea of a Lennox, go for a G23 instead. It really is 80% efficient.
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