Solar

How Do I Figure Out the Electric Load for my Appliances?

I am very interested to install a small solar system that would power our lights and water pump. We live in a new log home and use a wood-burning stove to heat the upstairs, and back up the stove with an electric heat pump. How would I figure out the electrical load for the appliances? I would think that I could use the electric bill for a month like April or October when the heat pump is seldom used. Jerry J. Columbia, SC

Jerry, Yes, check your electric bill for the Spring and the Fall to show your electric load without the heat pump. Once your get the lowest kWh readings per day in those two times it is pretty easy to minimally size your system, either to address your entire electric load or to dedicate your solar electric system to some of the important smaller electric loads. If you take a 15-year second mortgage (9%), it’s approximately $203 per month for a 2 kW system “with the works”. A lower percentage loan with some lower cost installed-PV system and maybe some added energy efficiency could probably get the cost below $150 per month. Cost depends on how you want to approach it. The National Renewable Energy laboratory (NREL) has guides to solar energy as does the US Department of Energy. Both have introductory primers that are all worth looking over as you consider a residential photovoltaics system.