What Size of Pool Heater Do I Need?

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What Size of Pool Heater Do I Need

As a pool owner, you need to choose an ideal pool heater size to ensure optimal pool heating. A large enough heater warms up the pool fast and efficiently.

However, the large the heater, the pricier it will be, and sometimes you might not even need the extra heating capability if you have a smaller pool. Therefore, the right idea is to match your pool heater with your pool size and specific needs.

That said, choosing the ideal pool heater size only requires you to consider a few basic things like your pool size, heating needs, and environmental factors.

1. Pool Size

The first and perhaps most important consideration when deciding on the heater to get is your pool size. It is crucial to match the heater to the pool size you have, which ensures fast and efficient heating.

You need to calculate your pool’s volume if you do not already know it. A simple way to do this is to find the surface area and multiply this by the average pool depth.

The surface area is the length multiplied by the width for those with rectangular pools. For L-shaped pools, you should divide the pool into two rectangles, calculate the surface area, and then add the numbers you get.

Regardless of the pool shape, you can still calculate the surface area and hence the volume. Once you know your pool size, you should choose a heater rated to heat at least that volume of water.

2. Your Heating Needs

Heating needs and preferences vary from one pool owner to the other. Therefore, as you choose your pool heater, you need to keep your specific preferences in mind.

Some pool owners prefer to heat their pool from cold to warm before swimming, while others want to keep it warm throughout.

Many heaters can effectively maintain your water temperature, but some might not work very well when you want to raise the temperature fast.

That said, you will need a larger and more powerful pool heater to raise the water temperature from cold to warm quickly. However, a smaller heater can still work for you if you prefer to maintain your water temperature at a certain level or heat the water gradually.

3. Understand the BTUs

Like most other heater types, your pool heater’s power is measured in BTU (British Thermal Unit). As you decide on the model to buy, you need to keep the BTUs in mind.

A high BTU pool heater is always preferable as it will help raise your pool temperature fast. However, you can still get away with a heater with a relatively low output by running it longer.

Another trick for getting the best service from a low BTU heater is running it when the pool is not in use to ensure the temperature will be ideal by the time you start swimming.

You do not have to struggle to do complicated calculations to determine how much BTU you need for your heater. Most manufacturers and pool equipment suppliers provide a chart for this. 

These charts provide BTU estimates for the most common pool sizes. For example, many of these charts recommend a 200,000 BTU heater for a 12’ x 24’ pool as it can raise the temperature by at least 1.5 degrees Fahrenheit per hour.

4. Environmental Factors

The environment has a massive impact on your water temperature, so you cannot afford to overlook it when picking a heater.

When the temperatures are very low, you need a more powerful heater to raise the temperature faster to keep the pool comfortable.

In these cold climates, the water temperature will drop much faster, and so your heater needs to be large enough to maintain optimal temperature.

On the other hand, you often do not need a massive heater if you live in hot areas. Unless you also plan to be using the pool at night when the temperatures drop, a small model that can maintain the temperature is often enough.

You might not even need to heat the pool in hot weather as cool water is more comfortable. Also, the hot sun will help raise the temperature significantly.

5. Other Variables

You need to consider other variables when deciding the size of your pool heater, such as how often you use the pool and whether you use a solar pool cover.

If you are an occasional pool user, you do not need a massive pool heater since you will not need to heat your pool that often. A small but efficient heater that can raise the temperature gradually and maintain it well should be enough. However, regular pool users are always better off with a larger and more powerful heater.

For those who use solar pool covers, the BTU requirements for their pool heater are much lower since it will help warm up the water and conserve heat. Using a solar pool cover together with a heater can reduce your BTU requirement by at least 50%.

Bottom Line

When it comes to choosing a pool heater, you need to make sure you match the size to your pool size.

Additionally, whatever you buy should suit your specific heating preferences and be powerful enough to raise your water temperature quickly.

As a pool owner, you should also know that by combining your pool heater with a solar pool cover and solar pool rings, you can ensure heating your pool will be more efficient and cost-effective.