Controlling Your Electrical Needs

One of the critical changes that owning your own power generation system imposes on you is being aware of your electrical current loads.  This is where your power goes to when you're using it.  We're going to cover  the basics of load reduction here; it's not part and parcel of setting up your PV system, but it's a major chunk of it.

Lighting

Get rid of your incandescent bulbs; the difference in lighting a room with incandescents versus compact fluorescents is anywhere from a 70 to 80% reduction in total loads used…and they're now about 1.5 to 2x as expensive rather than 5x as expensive, and most are now tolerant of modified sine wave inverters.  On the horizon are LED bulbs, which are about a 90% reduction over incandescents.

If you are installing a new system, direct current lighting is much more energy efficient than alternating current lighting. Direct current wiring circuits will use larger gauge wire than alternating current circuits (See Wiring and Safety). This, depending on the number of lights and the distance of your runs, could be a significant cost factor.

Heating Hot Water

This is another major source of load, in large part because electric hot water heaters are incredibly inefficient.  Electrical hot water heaters are usually the largest single draw on power in a home.  Consider a propane hot water heater, even an 'instant on' one without a storage tank, if you're up to doing a replacement on this, or installing a secondary solar thermal hot water heater.  At the very least, put more insulation on the hot water heater you have.

Air Conditioning

The first rule of living green is that air conditioning is expensive.  If you live in a dry climate, get an evaporative cooler; these systems cool air by osmotic flow over a moist pad.  If you're not in a dry climate, cooling fans and ceiling fans are a good choice.  If neither of those are palatable, look seriously at getting an Energy Star certified air conditioning system.  And, while it's counterintuitive to most folks, improving your home's insulation can dramatically cut your cooling bills or the draw that you climate control system makes on your power system.

Refrigeration Alternatives

Refrigeration is another major consumer of electrical power. Unlike stoves or clothes dryers, which are used only sporadically, refrigerators draw power 24 hours a day.  There are energy efficient refrigerators available that use only 25% of the power of a conventional refrigerator. However, these are relatively expensive and the power they consume is still substantial.  If you're using a propane water heater, or a propane generator as part of your power system revamp, look seriously at propane refrigerators.

Computers and Other Appliances

Today there is a wide assortment of 12V appliances on the market, from kitchen counter appliances, TV's, VCR's, stereos and small vacuum cleaners. You will have to decide what your needs are and whether these 12V appliances will meet them.
While many laptop computers can be run off of 12V- direct current power, most desktop computers, printers, scanners, etc. require the use of an inverter. While most computers and accessories will run off of a modified sine wave inverter with no problems, some computers (Apple) and laser printers, as well as some photocopy machines will need a pure sine wave inverter.

Water Pumping

One of the largest draws of electricity in rural areas, especially in the Western US, is pumping water to crops, for animals or livestock, or for household use.  One of the earliest uses of solar power was to power electric pumps for just this purpose.  They're also becoming more popular in residential areas to run sprinkler systems and misting systems for lawn care.