If you are only looking into a solar electric system to simply REDUCE your power bills a utility inter-tied system may be what you need. These systems do not require the above info, instead these systems are based on your allowed budget to determine system size. These net metering type systems feed power back to the utility - prices range from a few thousand dollars and up.

If you want a 'stand-alone' independent power system-Please Read Below. :

Without writing down the power requirements for the loads you wish to run, there is no way of determining even an estimated cost.

There is no 'average' that gives any useful information about what your specific needs will require.

  The square footage of a house or building does not enter into our calculations, only the location, amount of power used at the site per day and the peak load are useful to determine general system size and costs.