Swimming pools are fun!  They can add value to your home.  They are great for neighborhood gatherings.  They can make you the cool house on the block.  They can make holidays more festive.  They can keep kids busy during Summer time.  It is great exercise to swim. They add beauty and ambience to any backyard.  Regardless of the reason you chose a home with a swimming pool or had a custom one built, have you ever thought of extending your swimming season?  If you have, that requires a swimming pool heater.  Whether you are replacing an existing heater or adding one to your equipment pad, you have choices.

Natural gas, propane gas and electric heaters are all readily available.  Then you have to decide the size of the heater you want to buy.  When referring to the size of a heater, I don’t mean the footprint.  I mean the heat output.  In heaters, this is measured in British Thermal Units (BTUs).  The larger the heater, the higher BTU it will have, and the more quickly it will heat your swimming pool water.

Pro Tip:  Always go with the largest BTU your swimming pool can accommodate.  While it may be a bit more upfront cost, it will maintain less operating costs for the life of the heater by heating the water more quickly.  This means you get to jump in sooner too!

Natural Gas Heaters

These heaters are very popular in places, like where I live in California, because of their affordability to operate.  Electricity is very expensive here, so unless you have solar, an electric heat pump may not make a whole lot of sense.  You must have, or build, an existing gas line to operate a natural gas heater.  The size of the gas line, and how long the run of the gas line is, will determine the maximum size natural gas heater you can purchase and install.  Remember, size is referring to BTUs…not dimensions.

Dimensions can be important as well.  I will use myself here in California again as an example.  We tend to have much smaller backyards.  With a smaller backyard, you have a smaller equipment pad which can put limitations on the brand of heater you buy due to space.  Natural gas heaters tend to have a smaller footprint than electric heaters.  Not always.

Electric Heaters

Heat pumps are becoming more and more popular.  Depending on the climate a heat pump can be an excellent choice.  They work differently than natural gas heaters.  The end result is of course the same:  warm water.  But they operate off of the air outside and electricity.  Inside the heat pump there is a fan.  This fan draws air from the outside.  Then this outside air is directed over a coil.  Inside the evaporator coil is a liquid refrigerant. This refrigerant absorbs the heat from the outside air, turning it into a gas.  Then the warm gas in the coil passes through the compressor and heats the water as it passes through.

How Long Will a Heat Pump Take to Heat My Pool?

In doing my research for this article, I learned there is not a simple one line answer.  There are several factors that need to be attributed to answer this question.  I found a lot of good reading out there and have consolidated it for you here.  

The Temperature of the Outside Air

As I mentioned above, a heat pump draws air in from the outside, so how warm or cold the ambient air is plays a major role.

Pro Tip:  Heat Pumps are designed for temperatures above 45-50 degrees Fahrenheit. 

If the temperature is colder, the heater will not work efficiently and cannot warm your swimming pool.  I take that back.  It absolutely could, but it would take forever and cost a fortune.  

The BTU of Your Heater

As we chatted about above, the larger the heater,  (You guessed it, BTU!), the more quickly your electric heat pump will heat your water.  I learned that one BTU will raise one pound of water by 1 degree Fahrenheit.  We don’t measure our swimming pool in pounds do we?  Nope.  So, 1 gallon of water weighs 8.34 pounds.  In a nutshell, 8.34 BTUs heat 1 gallon of water 1 degree.  I hope this isn’t confusing you. This being said, the size of your swimming pool plays a role in how long it will take to heat.  The larger the pool, the more water.  The more water, the more gallons.  The more gallons, the more pounds.  Starting to make sense.

People often buy too small of an electric heat pump to save on the cost.  This is a mistake because you end up paying the difference, and more!, in operating costs.  Heat pumps don’t have to cost a fortune anymore.  We will talk more about that below.

How Hot Do You Like it?

No, I am not being coy.  It is an honest question.  How warm the water currently is and how warm you want it to be are obviously factors that will determine how long you need to leave your heat pump on for.

Pro Tip:  Always, always use a solar blanket when you use any heater.  75% of heat is lost off of the surface of your swimming pool.

To keep things simple, I learned it typically takes between 24 and 72 hours to heat with an electric heat pump, based on the factors above.

Remember When I Said Heat Pumps Don’t Have to Be Expensive?

Whether you go with a natural gas heater or an electric heater, it can get costly.  ANy sound investment has this commonality.  Heat pumps can tend to be more expensive than gas heaters.  But you don’t have to pay an arm and a leg.  You can get an economical, fast acting, name brand ComforTemp electric pool heater for about half of what you would find for another name brand heater at your local pool supply store.  These heaters come in a variety of sizes?  (We mean BTUs, remember?) to fit any swimming pool.

 These heaters will pay for themselves by cutting the cost of energy.  They are BT certified and come with the industry standard 1-year warranty.  My favorite part is the self diagnosis and easy-to-use displays.  Don’t believe me?  Check them out here. https://poolpartstogo.com/collections/heat-pumps

Whatever heater you decide to go with, remember…swimming pools are supposed to be fun!  Don’t stress about this purchase.  Do your research, like you are doing now, and treat yourself to a brand new heater.  An investment you won’t regret as you enjoy it for years to come!  See you poolside!