Lifestyles & Appliances

Solar Sizer

Lighting

Lighting Guide

Fluorescent lights are the most efficient, halogens use twice the energy for the same amount of light, and regular incandescent bulbs use four times more power than fluorescents. Artists prefer halogens for sharp color, workers prefer fluorescents for less shading. More important than using energy-efficient lighting is turning off lighting that isn't needed.

If your computer won't open the Flash version of the Solar Sizer, you'll have to do this the pen and paper way: for each table, pick the category that best describes your needs and write down the watt-hours. (If your computer will support Flash, click on the Solar Sizer tab above.)

Heating & Cooling

Solar Heating & Cooling Guide

Passive solar heating, with large insulated windows facing south, can pay for itself in months not years. Wood stoves and propane wall heaters are good for backup (they don't use electricity). Forced air and radiant floor systems (that aren't designed with electrical efficiency in mind) can consume much of your precious energy, when you need it the most: the dead of winter. We can assist with designing high efficiency radiant floor pumping systems that work on solar.

Air conditioning is NOT practical, except for super efficient evaporative cooling designs which only work well in areas with low humidity (below 40%). Fans are OK, as long as they're not left on continuously. Ceiling fans aren't recommended, simply because they are almost always left on continuously.

Water Pumping

Water pumping is your most important power use. Water system energy requirements can range from low to high. On the low end is a rain catchment cistern with a small DC pump. But if your well is deep (over 200 ft), if you are irrigating a garden, or if you have a large family that uses a lot of water for bathing, washing clothes, etc., you will use as lot of energy. The average American uses close to 100 gallons/day per person. Some solar enthusiasts use less than 5 gallons/day.

Refrigeration

Refrigerator Tech Guide

Kitchen Appliances

Most kitchen appliances, like microwaves, blenders, and pop-up style toasters, work fine on solar power. Even though they can use a lot of power, they usually are only on for a few minutes each day so the total energy they consume is low (that is, unless you live on toast). Crock pots, toaster ovens, coffee makers with a warmer plate, etc. are not recommended because they may stay on for hours. Use a coffee maker with an insulated carafe, it only takes power for 5 minutes when it's making coffee, then it's off.

Household Appliances

As before, appliances that stay on for long periods of time (like an electric blanket) are much more of a problem than things that are on for short periods (a hair dryer). Some new appliances like washing machines have computer controls that are not always compatible with mod-sine inverter or generator power.

Electronics

Electronics on Solar Guide

Most stereos, computers, and TVs work well on solar power. Unfortunately most also have what is known as "Phantom Loads," that is, they consume power even when turned off. This is to power their remote controls or built in clocks, etc. The solution is to unplug these devices when not in use or plug them into a switchable power strip. These phantom loads, while very small (under 20 watts), keep the inverter on 24/7, and can take several solar panels worth of energy production. Portable devices like jamboxes and laptop computers usually use much less power (and space) than desktop models. For example: a desktop computer uses as much energy in one hour as a laptop uses in 5 hours or more.

Power Tools

Most power tools work fine on solar power. If the inverter is large enough to initially start the motor, it should continue to work. Most tools are really on for just a few minutes at a time, so even though they take a lot of power, it doesn't add up to very much total energy. Air compressors can take a huge amount of electricity to start, so even though their total energy consumption may not be huge, you may need a large inverter to actually run one. Big tools require big inverters.

The Bottom Line

Add up your watt-hour choices from each section to get your Total Watt-hours per day. This number may be as low as 1000 watt-hrs (1 kWh) or it may be as high as 20,000 watt-hrs (20 kWh).
If it is high you need to start changing your planned lifestyle, because that lifestyle could cost you a fortune.
Check out the Package systems to get an idea what price range you fall in.

For a more accurate load analysis, print out our Solar Sizer Basic (PDF)

For the technically minded that are ready, you can download our Solar Sizer Excel Spreadsheet.