Picking the Right Size Pool Heater

There’s nothing worse than getting into a pool or spa that isn’t properly heated. Cold water can really ruin what is supposed to be a relaxing and enjoyable experience. Oftentimes, people don’t pick a heater with the capability of properly heating that particular pool or hot tub, or just have no idea what size they need in the first place. We’ve created an infographic for that express purpose: to help you pick the right size pool heater.

Pool and spa heaters help your water (which is constantly losing heat through the surface area of the water) maintain a warm temperature so you can have an enjoyable and extended swimming season. A pool heater works by using fuel to create heat to warm water drawn from a pool and then returning the warmer water to the pool to raise the temperature.

Pool heaters are rated according to their output in terms of BTU which is shorthand for a measurement known as British Thermal Units. One BTU raises the temperature of one pound of water by one degree Fahrenheit.

If you have a heater with a high BTU count, it means that heater is capable of heating water in a pool or spa quicker than one with a lower count. You also will need to take into account the size and shape of your pool or spa in order to pick the right heater for your pool.

You’ll first need to establish the surface area of your swimming pool to determine what kind of BTU output you’ll need from a heater. If you reference the infographic in this post, you can calculate that number for a rectangular, round, and oddly shaped swimming pool.

The more surface area on your pool, the more chance heat has to escape. This also means you will need more BTUs to adequately heat the water initially and maintain heat from day to day.

Note: If you need to heat an indoor pool, divide that surface area number by three as it takes much less to maintain the heat of a pool inside.

When it comes to hot tubs, you will want to know two things to find an appropriate heater: the size in gallons and the time required to raise the temperature of the spa/hot tub by 30 degrees Fahrenheit. Use the table in the infographic to know the right heater size for your spa.

A pool or spa heater is the most effective way to maintain the heat in your water, but it can be really tricky to find the right size and BTUs can be confusing. Hopefully you can use this infographic to find the one for you!