Power tips: If you’re thinking of upgrading your generated power, remember that anything that makes heat with electricity (electric heat, water heaters, dryers, etc.) uses relatively huge amounts of power compared to other loads. If your house heats with electricity, consider another heat source or be prepared to buy a large generator.
Motors that start under light load (well and septic pumps, many fans) require two to three times the starting power than they do to run while those starting under heavy loads (refrigerators, compressors) may take as much as five times to start. A “rule of thumb”: Allow 2-3 KW of generator power per horsepower of electric motor.
Electronic loads (particularly newer computers) take relatively little power, but that power must be clean and stable (well-regulated voltage and frequency with low harmonics). But computer electronics have properties that produce difficulties for the power source. If you are planning backup power for computer networks a “rule of thumb” the total electronic load should not exceed 50 percent of the generator’s capacity. Besides, there’s always the air conditioning that needs to keep running to keep the computers cool.