Swimming Pool Blog

Electric Pool Heater for Small Pools?

Electric Pool Heater for Small Pools?
Rob Cox  September 07, 2016


Can you put an electric pool heater on a swimming pool? Yes and No. There's been a renewed interest in electric pool heating, but there is also some confusion about how to use electricity to heat swimming pools.

There are two types of electric pool heaters, Resistance Heaters and Heat Pumps. Resistance heaters use an immersion element that heats the water as it flows through the heating chamber. Heat pumps, also electric, absorb heat from the surrounding outside air using an evaporator, compressor and condenser to heat the pool. Like a reverse air conditioner.

Both types of electric pool heaters require hard wiring, 240V, neither can be plugged into an outlet. Resistance electric pool heaters (those with heater elements), need a lot of amperage, 100-150 amps, or 2 or 3, 50 amp circuit breakers. Pool heat pumps only require a single 30-50 amp breaker.


cost to generate 1 million BTU's - image by RheemAnd herein lies the problem with resistance heaters. They are Expensive to Operate, or very expensive I should say, when compared to other heating methods. It takes a lot of amperage to heat up even a small pool, and when it comes to your energy bill, what you really pay for is amps. 

Pool Heat Pumps, on the other hand, draw only about 30 amps, for a 100K BTU unit, and only 15 amps for smaller 50K BTU heat pumps, used on small pools or aboveground pools. 

A pool heat pump uses about the same amount of juice as a 100 watt lightbulb, and can heat a pool for just $2-3 dollars per day. Install an electric resistance heater however, and you can spend $10-15 dollars per day, easy.

It's so tempting to take a look at these cute electric pool heaters (one model shown here) that promise warm water for up to 11,000 gallons.

Don't be Fooled! This small electric 'pool' heater, even at 27 kw, is not going to heat much more than 3000 gallons, and unless you have an insulated spa cover on your pool, it can cost hundreds of dollars per month to use, even on a small pool. Plus, you'll have a high electrician bill, to add 100 amps to your breaker box, and a buried power line to the heater, which is not really even weather-proof, so it needs a shelter.

Electric element heaters are great for hot tubs, but not pools. If you want an electric pool heater, buy a pool heat pump, they are more expensive than resistance heaters, in the $1500-$3000 range, but will heat your pool effectively and efficiently.

So No - swimming pools, even a small pool, should not be heated by an electric pool heater. Heat Pumps, Yes! But Resistance Heaters, NO...

That is all for now, carry on.


- Rob