One of the most common questions asked by anyone installing a pool boiler for the first time is “what size pool boiler do I need for my swimming pool?” Unfortunately, though, there isn’t a single answer to this question. This is because the response depends on several factors. Firstly, it comes down to your personal preference – how quickly do you want your pool to heat up, and what temperature do you want the water to be? Secondly, the answer also depends on where the pool is located. A swimming pool located in a warm part of the country requires less energy to warm its water than one in a much colder spot.

With this in mind, it’s impossible to give a definitive response. Therefore, this article gives you a broad idea of how to determine the best sized boiler to suit your swimming pool.

Will My Supplier Tell Me Which Size Boiler To Buy?

While you could ask your pool boiler supplier which one is best for your needs, you can’t guarantee that their answer will actually be the right one for you. The supplier could be recommending you a boiler that simply isn’t suitable, or one that goes above and beyond your requirements. Therefore, you need to be aware of the basics of how to calculate the correct size of boiler so that you can make a well-informed decision.

How Do I Calculate The Correct Boiler Size?

You shouldn’t just install the biggest size of gas boiler in the hope that doing so will guarantee you trouble-free heating. Yes, this will ensure the water in your pool heats more rapidly and will say warm even on the coldest days, but it will also come at a high price. The most powerful boilers use considerably more gas than a less powerful one, and this will take a serious toll on your energy bills.

Working Out The Surface Area

The first step, then, is to work out the swimming pool’s surface area. The sun’s rays shine on the surface of the pool and their heat passes through this membrane. It’s also this membrane that the heat escapes through on cold days. With this in mind, the bigger the surface of the pool, the more powerful the boiler needs to be to keep your pool water at a higher temperature than the air’s ambient temperature. It also explains why the average cost of heating your pool will be much higher in a cold climate than in a hot one. You can work out the surface area of your pool by pacing out its width and length using even steps, working out how long your pace is, then applying the result.

Determining BTU Requirements

Next, you need to determine your BTU requirements. For example, if your swimming pool measures 360 square feet in total, you should divide this area by 3. This makes the basic BTU requirement 120. Yet, that doesn’t mean that buying a 120,000 BTU pool boiler is necessarily the right course of action. You then need to take into account the environment factors that will impact on the calculation.

Fine Tuning The BTU Requirements For Your Pool

The perfect BTU rating for your pool boiler will depend on several qualifying factors. These include:

  • How much effect the wind has on the surface of the water
  • The average temperature of the air in the location of your pool
  • The average night time temperature year-round
  • Whether the humidity profile is low or high

You can incorporate those factors by first deciding how hot you want your pool to be once the thermostat has cut out, then by finding out the average temperature of the air during the coldest month that you’ll be using your pool. Finally, take the figure for the air temperature from the temperature you wish your pool to be and this tells you how much you need to be able to warm up the pool. Once you’ve done this, you can calculate the ideal BTU rating by using this formula: Desired rise in temperature x the surface area of the pool x 12

How Can I Help My Pool Heater To Work More Efficiently?

Keeping your pool warm during the winter can be a major struggle. When your boiler pumps out heat, that heat keeps on transferring to the cold air above the surface of the water. Even worse, the hottest water will be just under that level since heat will rise in water. You can keep heat in the pool water, though, by using a thermal cover. Even better, use a complete enclosure. This will ensure that the pool heater can work as efficiently as possible.