If I manage to get to below 500kWhrs a month, what would it cost to put solar panels on my roof? Assuming I have enough roof space, the going ball park cost per watt is $8-$10 Watt. According to PVWatts I need about a 5,000 Watt system. PVWatts is a great tool! I will use $9 a Watt. 5000 Watts x $9 x 0.7 (Federal Credit) = $31,500. Think of its as buying as car. But in ten years the car will be worth virtually nothing and the system will still be worth at least half of its installed value. And to top it off the system will be making you money! In my case not as much as some. (My rate is about $0.10 a kWhr.)

PVWatts assumptions.

De rating factor of 0.80
Array Tilt of 45 degrees.
Array Azimuth of 200 degrees. (House does not face due south)

The output from PV Watts is (“Year”, 4.36, 5973, 595.81). The middle number is a yearly output of kWhrs. This number divided by 12 is about 500 kWhrs.

This would be a grid-tie system. So I would not be able to “ride out” a storm with lights if the power fails. The power very rarely goes out, but it would be great if I did not have to worry about outages. But, grid-tie usually yields higher efficiencies. If the state offered some additional incentive I would seriously consider a solar system. The next power reduction upgrade is a new Heat Pump. This will replace the Gas Furnace and the AC unit. I currently have a 80% efficient Gas furnace and a SEER 10 AC unit.

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