1. Find your last 12 months electric bills or call your utility; you will need your average daily usage for a full year's
climate cycle.
2. Total the kWh from all 12 of your monthly electric bills and divide it by 365 days to get your average daily usage.
(KWh equals 1000 watts)
3. Look on a Solar Isolation Map and find the average Peak Sun hours for your area.
4. Divide line two (average daily usage) by line three (Peak Sun Hours).
5. Add 15% to allow for heat losses in the solar modules, voltage loss in long wire runs and power loss in the inverter (all
electronics use power even inverters use energy to operate).
6. A shading survey would be helpful to track the suns path and give the effect a tree branch; fence or house will have on
your solar production. Add this percentage to the above.
You now have the size of the solar array required to completely eliminate your electric bill.
You now have the information needed to find a grid tie kit system to fit your needs. Not all systems will fit in the roof space
of your home, In such a case you may need to think about a ground mount system. Either way you go we have been
designing solar electric power systems for years and can design a system for your needs.