Energy Efficient Home and Garden Products
Home & Garden Products
Energy efficent appliances are essential to living "off grid" or just reducing your total energy usage. In particular refrigerators and freezers can account for almost 15% of your electrical usage!
Efficiency and Energy Conservation in Appliances
The use of energy-efficient appliances and lighting and non-electric alternatives, can make solar electricity a cost-competitive alternative to gasoline generators and, in some cases, utility power. Outlined below is information on typical energy consumption for various appliances and lighting.
Cooking, Heating and Cooling
Each burner on an electric range uses about 1,500 W, which is why bottled propane or natural gas is a
popular alternative for cooking in an off grid home. A microwave oven has about the same power draw, but since food cooks
more quickly in a microwave oven, the amount of kilowatt hours used is typically lower. Propane, wood
or solar-heated water are generally better alternatives for space heating than electric baseboards. Good
passive solar design and proper insulation can reduce the need for winter heating. Evaporative cooling is
a more reasonable load than air conditioning and in locations with low humidity, it's a great alternative.
Lighting requires careful study since type, size, voltage and placement can all significantly impact the
power required. In a small home, RV, or boat, low voltage DC lighting with LEDs is often the best choice.
DC wiring runs can be kept short, allowing the use of fairly small gauge wire. Since an inverter is not
required, the system cost is lower. In a large installation with many lights, using an inverter to supply
AC power for conventional lighting is also often more cost-effective. AC compact fluorescent lights and now LED lights are
common and efficient, but it is a good idea to have a DC-powered light in the same room as the inverter
and batteries in case of an inverter fault. Finally, AC light dimmers will only function properly on AC
power from inverters that have sine wave output.
Gas powered absorption refrigerators can work well in small systems when bottled gas is available.
Modern absorption refrigerators consume approximately 5-10 gallons of LP gas per month. If an electric
refrigerator will be used in a standalone system, it should be a high-efficiency type such as the Sunstar or Sunfrost units for
upright units or a Steca or Sundanzer chest style units. The chest style generally have better energy efficiency since the
cold air is less likely to escape when the door is opened however they are not always practical to have in kitchen area.
All these units are available both as High-efficiency DC refrigerators or with AC power adaptors and can offer significant
energy savings over convential AC units.
The standard AC electric motors in washing machines, larger shop machinery and tools, swamp coolers,
pumps, usually ¼ to ¾ horsepower and consume relatively large amounts of electricity thus requiring a
large inverter. Often, a 2,000 watt or larger inverter will be required. These electric motors can also be
hard to start on inverter power, due to large surge loads. They are also very wasteful when compared
to high-efficiency motors, which use 50% to 75% less electricity. A standard washing machine uses
between 300 and 500 watt-hours per load, but new front-loading models use less than half the power.
If the appliance is used more than a few hours per week, it is often more economical to pay more for a
high-efficiency appliance rather than make the electrical system larger to support a low efficiency load.
Vacuum cleaners usually consume 600 to 1,000 watts, depending on how powerful they are, but most
will operate on inverters as small as 1,000 watts since they have low-surge motors.
Many small appliances with heating elements such as irons, toasters and hair dryers consume a very large
amount of power when they are used but, by their nature, require only short or infrequent use. With a
sufficiently large system inverter and batteries, they will operate, but the user may need to schedule those
activities with respect to the battery charging cycle. For example, by ironing in the morning the PV system
can then recharge the battery bank during the day. Electronic equipment, such as stereos, televisions,
VCRs and computers, draw less power than appliances with heating elements, but these loads can add up,
so opt for more efficient models when possible, such as an LCD TV instead of a plasma or CRT design.