Sizing an Off Grid Solar System
Determining how much power your solar PV system needs to produce for off-grid living is similar to sizing a grid-tie solar system, except that there is no utility bill to refer to for historic usage. So, the first step is to make a comprehensive list of your electrical loads – all the items you plan to power in your off-grid home. Just remember that the more power you use, the more you will need to produce.
For the most accurate calculations you can refer to the label on each appliance or piece of equipment, estimate the amount of time you will use them each day, and then do some math. For some items, it is reasonable to use a guesstimate, but for those that have higher power consumption or that are in use frequently, we suggest using the actual electrical load ratings when doing off-grid calculations.
It is generally not cost-effective or feasible to install a renewable energy system large enough to provide power for things like electric heat, air-conditioning, electric cooking or electric hot water. Geothermal, solar hot water, and of course, gas appliances, are just some of the alternatives available that will allow you to maintain a comfortable lifestyle without relying on utility power.
Once you know how much power you use, you can proceed to sizing your solar PV system. In an off-grid application it is critical the system is properly sized, because you will not have utility power to draw from if your power system does not provide enough to meet demand. That is why we recommend getting professional help from an expert off-grid system designer, so you can be sure that you have all the power you need when you need it.