Power Factor Correction to Save Energy

There have been a variety of products over the years pitched to correct power factor in homes to save energy. The pitch goes something like this:

Your homes has all kinds of motors (inductive loads) like pool pumps, air conditioners, refrigerators, washers, dryers, and even vacuum cleaners. Those electricity using appliances all have a power factor that is less than 100%, meaning you are wasting energy and increasing your electric bill unnecessarily. We have a gadget that you install to correct power factor in your home, and you will save X% on your electric bill!

Devices are often called Power Factor Correction Devices or KVARs. It all sounds great, right? There is one problem… they don’t do what they says, namely, reduce your electric bill!

Power factor is a measure of efficiency. It is the amount of kilowatts required as a ratio of kVA (volts times amps) that the utility company needs to deliver. When you run an appliance that has a power factor less than 100%, the utility company needs to deliver more power (in kVA) than the appliance uses (in kW). That’s not your problem. You are only billed for the actual kW power consumed.

In Florida (and the rest of the U.S.) residential users of electricity are billed on the basis of kilowatt-hours (kWh). This is the basic unit of energy that your electric meter measures. The meter doesn’t care what the power factors of inductive loads are. If you improve the power factor of anything on the home’s side of the meter with one of these power factor correction devices, the appliance still uses the same kilowatt-hours of electricity. The utility will need to deliver less actual power to meet the kilowatt usage. That’s great for the utility company, but it does absolutely nothing for you.

There are a lot of power factor correction devices on the market, and even some reputable electrical contractors advertise them. Sadly, even licensed professionals get duped by manufacturers of these worthless devices.

While on the subject, there is a pool pump being marketed and installed in Southwest Florida that claims to have a power factor near 100%. For the same reason, it doesn’t matter. Having a power factor of 100% does nothing for your electric bill. Using that as a sales feature is a ridiculous claim. If you want a truly inherently efficient pump, use a variable speed pump with a permanent magnet motor. For the same price of the 100% power factor, 2-speed pump, you can get a more powerful and real variable speed pump that actually saves money and meets a wider range of needs. If you can’t afford a variable speed pump, a properly sized and controlled two-speed pump works in many applications, but our clients are unquestionably happier with variable speed pumps. Some people want to explore solar pool pumps, but the best use of your money is a good variable speed pump, and stop worrying about the power factor!

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