Too much insulation?
Mike wrote:
This summer, I upgraded my walls to R20, attic to R40, replaced metal single
windows with double low-e argon vinyl, replaced all wood doors with
insulated steel, air sealed the house and replaced a 30 year old 120k gas
furnace with a 75k condensing unit. The old furnace used to run every 5 out
of 15 mins at 0C, now it runs 10-15 mins every 3-4 hours. Something doesn't
seem right here as my neighbors runs 2-3 times per hour and it's a 100k
furnace in approx the same sized house with similar insulation (maybe 20%
less) I have my tstat set to +/- .5C and CPH disabled.
Don't follow the question (if there is one?). What doesn't seem
"right"?
I see a former case of running 1/3-rd the time, now only about
1/16.8-th of the time (using mid-points of on time and interval given).
That seems pretty good to me. It seems to be taking 2-3X the "on"
time to raise the temperature from "on" to "off" with something under
2/3-rds the capacity of previous (assuming same efficiency which was
probably also worse for older unit) so that also seems quite
reasonable.
Trying to then do something w/ the neighbor's "data" w/o any more
factual basis than this seems futile.
So, I'm at a loss as to what you're asking/expecting...
|