What size generator do I need?
It is very important to choose the right sized generator for your needs. If you choose a generator that is too small, you will not be able to run your essential appliances during a power outage. Further, overloading the generator may lead to its breakdown as well as damage to all appliances that are using its power.
On the other hand, if you choose a generator that is too big, you will be spending more on its purchase, installation, fuel, maintenance and repairs than required. Choosing a generator that is too big may lead to a huge and unnecessary initial cost.
The size of your generator depends on the number and type of electrical appliances that you plan to run. Heating and cooling appliances like air conditioners and refrigerators consume a lot of power. You will need a bigger generator to power such appliances. On the other hand, if you want your house to power lights, you can opt for a smaller generator.
Furthermore, appliances that have moving parts like fans and pumps consume a lot of electricity at start-up but do not require a lot of power to continue functioning. When electric motors form part of your appliances, you will need to multiply three times the motor horsepower (hp) to your required steady state load.
The first thing you need to do is work out your Total Electrical Load, using the power chart below. Then, you will need to establish your steady state load, such as lights and appliances, which you expect to operate at any one time.
Above chart is a guide only and some appliances will vary their watts depending on brand.
To convert Watts to kVA @ 0.8pf, divide Watts by 0.8.
2000 Watts = 2.5 kVA
4800 Watts = 6 kVA
To convert kVA to kW @ 0.8 pf, multiply kVA x 0.8
CHOOSING A GENERATOR
Power tools rated up to 1000 watts. Portable Drill, Jigsaw, Toaster, Frypan, Lighting, Heating, TV, Small Fridge, ¼ to ½ hp Motor (depending on type). Ideal for the “Home Handyman”. Light in weight to power small appliances and for home use. Choose 2.4 kVA.
Power tools rated up to 2200 watts. Small Air Conditioner or Radial Saw, Lighting, Heating, TV, Microwave, Oven or Hotplate, Small Submersible Pump, ¾ hp Motor (depending on type). Choose 4.4 kVA.
Power tools rated up to 3400 watts. Small Air Conditioner, Radial Saw, Lighting, Heating, TV, Microwave, Oven or Hotplate, Submersible Pump, ¾ to 1 hp motor (depending on type). Choose 7 kVA.
All information above is an approximation only.