this house has a 2 yr old Sunny Boy 2100u system installed. 4BR, 2.5 Bath House.

Best answer:

Answer by billrussell42
If you have 8 hours of sun a day, that is 2100*8 = 16800 watt hours of energy, or 17 kW-hrs.

17 kW-hrs purchased from the power company is about $ 1.70, so you will save about $ 50 per month.

This assumes power costs 10¢ per kW-hr

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