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razl_gw

What do you think of my energy usage

razl
16 years ago

I have a 3200 SqFt house in Stonington, CT. Since it was a new contruction, the installer ran a heating load with a mid range air infilitration, which called for roughly 5-tons heating, but being a 2 zone, he installed two 3 tons Closed Loop GSHPs. After moving in, I added more insulation to the attic (R-30 to R-49)and had the heating load calculated again with a blower door test.

The results are as follows:

Annual Load 42 Mbtu/yr

Annual Energy 22.0 Mbtu/yr

Heat Loss 34.9 kBtu/hr

Output Required 40.1 kBtu/hr

So I guess this shows that I could have gotten away with two 2-ton units, right? Since I been there over a year, I have logged by kw/Hr usage:

Month Usage in KWHr (Avg Temp)

Jun 536 (69F)

Jul 954 (76F)

Aug 828 (75F)

Sep 588 (65F)

Oct 790 (54F)

Nov 1133 (43F)

Dec 1172 (40F)

Jan 1553 (36F)

Feb 2022 (23F)

Mar 1549 (35F)

Apr 1199 (46F)

May 625 (60F)

Of course the KWHr used includes lights & appliances, but I think that averages around 530KWh per month. For example, during Feb, the coldest month, you coul say I used 1492KWh for heating.

So what do you make of my "oversized" system?

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