how to heat a pool the right way

How To Heat A Pool – 4 Common Ways

The need for heating your pool varies by region. However, it’s always a nice-to-have feature. In northern states (Chicago, New York, Boston), it’s essential unless you only wants to swim for a few months. Therefore, you need to know how to heat a pool to be able to enjoy the pool for longer periods of time. While adding heat will increase the pool’s price, it’s absolutely worth it.

There are more than 4 ways on how to heat a pool but we have explained the most common methods in this article. Other methodologies not discussed are oil fired heaters, wood fired heaters and heat exchangers on a main boiler. These are not used very much and are widely being phased out by the pool industry. Here are the 4 options you’ll likely be presented with by your local pool builder.

4 Pool Heating Methods

  • Natural gas or Propane
  • Electrical Resistance
  • Electric air source heat pump
  • Solar
how to heat a pool homeowner guide

How To Heat A Pool With Natural Gas or Propane

Your first option is a natural gas or propane heater. These act like a house boiler and use fire to heat the water.  That’s over simplifying the process, but you get the idea.  To hook up one of these heaters you need to be a licensed plumber. This is due to the gas connections required and the venting for the exhaust gasses. 

These heaters come in different efficiency ratings. This is a good metric to check before you make a purchase. However, it’s not the only thing to consider. You should also look at consumer reviews for the heater you consider buying.  One heater may have 96% efficiency (very good), but have an expected lifespan of 3 years. While another may have an efficiency of 84% but have an expected lifespan of 10 years.

How To Heat A Pool With Electrical Resistance

Electrical resistance heaters are typically the most expensive type to operate.  These generate heat through electricity running through a conductive material in the resistor which gives off heat through electrical resistance.  These are commonly used on prefabricated hot tubs and sometimes on commercial spas, but rarely on residential pools and spas.  They do the job of heating well, but their electricity use is astronomical and when compared to fossil fuel heaters they most often are much more expensive to operate.

How To Heat A Pool With Electric Air Source Heat Pump

The electric air source heat pump or simply “heat pump” is the economical choice for heating your pool in most locations.  However, they do not work well in states with temperatures below 40 degrees fahrenheit. This can be frustrating for those who like to extend the swim season.  Also heat pumps are slow to increase temperature when compared to either of the above options. 

They work the same way an air conditioner works, only in reverse.  The fan pushes the outside are across the evaporator coil where refrigerant liquid is warmed by the outside air and becomes a gas.  Then this gas is then run through the compressor where the heat is increased before running through the heat exchanger where the heat from the gas conducts through to the pool water as it runs through the heat pump. 

The pool water takes the heat from the gas and the refrigerant becomes a liquid once again and the process can start again.  Air source heat pumps are an excellent choice for a pool heater if you live in a warm climate, or only plan on using your pool in the summer months in a cold climate.  If you plan on heating a spa in addition to the pool, you’ll need to consider other options in addition to the heat pump or In lieu of the heat pump.

How To Heat A Pool With Solar

Solar heat is the best choice for many in the southwest where sunny days are plentiful.  Solar pool heat is not photovoltaics, as in there is no electricity being produced.  Instead there are solar collectors made up of small water tubes installed on the south / southwest facing roof which allow the sun to radiate heat over a large square footage of tubing.  As the water circulates through these collectors, the water temperature increases. 

Obviously these systems only work well on sunny days. However, the heat is basically free. You only need to pay for the electricity to circulate the water which you’ll already be doing if you have a pool.  Solar collectors can also be used to cool the water.  When used at night, these same panels expose pool water to the ambient air temperature over the total square footage of the collectors and can reduce the pool temperature.  This is especially useful in the southwest where pools can become too warm.  A problem those in the northern climates can only dream about!

Bottom Line On Heating Pools

Now you understand the options you have for how to heat a pool. While there is no “right” way to heat your pool, we have some recommendations. If you have a spa, a gas or propane heater is definitely the right way to heat your pool. Additionally, from our experience in three different pool regions, we feel that solar is not used nearly enough. If you’re in a southern state, consider solar as your top option. When in doubt, consult the pool builders in your area. They will know what’s best for your backyard and region.


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