Alex wrote:
wrote:
buffalobill wrote:
....
There's no harm in having an oversize unit for a year until you do the
addition. The bigger question is, did they do a manual J to figure
out what size you needed? 4 tons sounds like a hell of a lot of
capacity for 2100 sq ft. average construction house. Also, they should
have verified that they can get proper ducting to the new area as well,
figured out how it's gonna be done, etc, so that it can be integrated
in. I would have made sure of that, so there are no surprises later on.
Hi,
Ducting to the garage shouldn't be a problem... the attic is pretty
much open and the duct work from what I can tell can be easily patched
in.
As for the 4 ton for 2100 square feet, it's my understanding that 1 ton
is suggested per 500 square feet, so 4 tons for 2000 square feet. Is
this not correct? We're at 1660sqft now, and the AC is installed and
working. It's blowing more air then I thought, but the intsallers said
once the addition is added that will go away.
Thanks,
Alex
One ton per 500 sq. ft. is like a stopped clock: it is right twice per day.
There is so much that differs from house to house to change the heat load
other than floor area:
Wall area
Wall insulation
Window area
Window type (single pane, double pane, low-E)
Window exposure (direction, overhangs, shade)
Floor insulation
Ceiling insulation
Regional climate
etc.
The windows are probably where the most variation in the
heat load can occur.
Unfortunately, few AC contractors seem to want to heat load
calculation, but just use that terrible rule-of-thumb.
They don't care about wall or window area or insulation
thickness.
My last house had 4 tons for under 2000 sf. and it wasn't adequate
(R-11 walls & ceiling, no floor insulation, northern california).
I just got AC installed in this house and none of the contractors
would do any real heat load calculations. This house has R-19
wall, R-30 floors, and R-30+ ceilings. We will see how this works.