BEopt: Too good to be true?
Has anyone used BEopt software? Are the results reliable?
I entered my design into BEopt. I had to create many of my own options. For instance, there was no description for my R22 exterior foam. I think I understand the process and how to use it.
Detroit, Michigan (CZ5)
1040 sq. ft.
71° heating set point
76° cooling set point
11 ft. walls. (There is no option for my shed roof design so I averaged.)
R40 walls (Nominal R22 external EPS and R21 batts downgraded for framing)
R80 vented roof (24″ cellulose in â‰¥ 30″ parallel chord trusses.)
R20 8′ basement walls and floor (I think. The category wasn’t clear.)
305 sq. ft. U1.9 windows
2 Fiberglass doors
1 air change per hour at 50 pascals
Electric resistance water heating
Standard clothes washer
Gas clothes dryer (0 CFM. Existing dryer will be located in detached garage/shop.)
10 KW PV (Meant to cover future electric car.)
I dialed back hot water usage. In retirement, we don’t take frequent showers or wash a lot of clothes.
The results show 4801 KWh/y with 6756 KWh/y PV surplus. This is beyond my expectations. Can I trust the results?
I’ve attached the BEopt output graph.