When you consider smaller off-grid systems, phantom loads can make or break a system. A 5-watt phantom wastes 120 watt-hours (Wh) per day. If your large home system or on-grid home uses 30 kilowatt-hours (30,000 Wh) per day, 120 Wh is small change. However, for small off-grid systems—for instance, ones that may generate less than 1 kWh per day to power some lighting—any phantom load is bad news. And in a typical home, the phantoms can easily add up to 5 kWh or more per day.
If you must have appliances that are phantom loads, I suggest pre-wiring switched outlets in your new home, so you can easily turn off the phantoms when the appliances are not in active use. Less graceful alternatives are plug strips, individual switches, and pulling the plug. The most common phantoms in a modern home are found in the computer center, entertainment center, and kitchen. Take a watt-meter into the store to check for phantoms before you buy, if possible.
When it comes to making load choices, off-grid folks without deep pockets always focus on efficiency. Here’s some specific advice on common appliances, drawn from my 30 years of off-grid living experience.
• Refrigerator/freezer: Set your sights on extreme energy efficiency here, since this is frequently the biggest electrical load in an off-grid home. Refrigerators and freezers cycle on and off continuously, and need to run regardless of sun and wind—you can’t flex your use to accommodate the variations in weather. Using specialty DC appliances may be a good option in some cases, and getting accurate numbers on energy use before you buy any refrigeration equipment is the best idea. Prepare to spend more up-front for better overall cost savings over the long term. At least one ultra-efficient fridge is also available in an AC configuration for about the same cost.
• Lighting: Off-grid homes of sensible design have no incandescent lights. Compact fluorescent lights (CFL) and LEDs predominate. Try a variety of CFL and LED options, since quality, color rendition, and light output varies.
• Clothes washing/drying: Horizontal-axis (generally front-loading) machines use less electricity (and less water, requiring less water heating and pump operation) than top-loading vertical-axis machines. Check your machine for phantom loads and use a timer or switch when necessary. Off-grid homes will rarely use an electric dryer, and if solar energy (a clothesline!) can’t be used, a propane dryer is an option.
• Motor loads: In the old days, I switched most of my woodshop motors to DC, a smart move in those days of inefficient inverters. Today, it makes sense to choose high-quality, sometimes variable-speed AC motors; whether for pool pumps, heat-pump motors, shop tools, or anything else that is motor-driven. The bottom line is found with your watt meter, which will tell you how much energy is being used.
• Computing/office electronics: A single word gives you the core of my advice here—laptops. These typically use half or less what a desktop machine uses, and they also incorporate a battery, so in times of very low renewable input, you can still use your computer for awhile. Peripherals—printers, routers, modems, backup drives, scanners, etc.—often are phantom loads, so put them on individual switches and turn them on only when needed. These peripherals do not usually need to be on for long periods of time, so ultra-efficiency may not be as crucial as for the computer itself.
• Solar hot water systems: For off-gridders, solar hot water systems reduce the need for propane—making hot water with solar electricity is not an intelligent option. Often it’s wise to make the electrical portion (for the solar pumps) separate from your main system to reduce the unpredictable load on the main electrical system. I like PV-direct systems that use a dedicated PV module to run the SHW system pumps.
Being aware of your energy resource can make off-grid systems much more effective. Off-gridders soon learn that it’s better to do laundry when it’s sunny than to draw on limited battery capacity and do it at night.
Well-designed off-grid systems will produce a significant surplus of energy at times, since they are sized based on the worst-case scenario. Instead of wasting this energy, you’ll want to take advantage of it.
Having “opportunity loads” to use surplus energy is a good strategy. At times, I can get a lot of my winter firewood cut with an electric chain saw, using energy during long sunny days, or during long windy times when much of the energy would be wasted. This has the added benefit of avoiding the noisy, polluting, gasoline-powered chain saw.
Focusing on energy efficiency in your appliance purchasing and operation choices can save money on up-front system cost. It also will reduce your pollution, ongoing generator costs, and battery replacement costs.
The advice here is crucial for off-grid folks, but also useful for all users of electricity. Taking the off-grid, ultra-efficiency mind-set into your on-grid home will shrink your bill, your footprint, and the cost of your future renewable energy system, too.
Ian Woofenden has lived off-grid for almost 30 years in northwest Washington’s San Juan Islands, and lives to tell the tales.