# How to Heat Your Pool With Solar Pool Heating

If you are currently in the market for a gas pool heater to suit your in-ground swimming pool, you are quite possibly a little overwhelmed by the choices available and the terminology used to describe them as well as all the numbers which are suddenly thrown at you. How can you hope to make sense of all this? How can you be sure you are making the right decision when it comes to your pool? Read on and you will learn that it is not as baffling as it all seems at first.

There are a couple of bits of terminology you have to come to grips with before you can start to understand pool heaters. The first is BTU. This stands for British Thermal Unit and is, in simple terms, the amount of heat (energy) required to lift the temperature of one pound of water by one degree Fahrenheit. Straight away you can see that if you know how many pounds of water your pool holds you can start working out how much heat is required to warm the water by a certain number of degrees F. It is usually used as BTU per hour although it is not normally written this way.

The second term to understand is “efficiency”. This is a measure of how well energy (such as natural gas or propane with gas pool heaters) can be turned into heat in your pool water. In an ideal world all the gas would be converted into heat which would mean efficiency of 100%. unfortunately, in the real world things are not quite so good and most gas pool heaters have an efficiency between about 80% (for example, the Hayward H-Series Millivolt heater is rated at 81%) and top out around 95% (for example, the Jandy Hi-E2 heater rated at 95%).

Getting the idea? Okay, let’s have a look at a heater and break it down. Let’s look at the Jandy LXi series of gas pool heaters. Most pool heaters come in a range of heating capacities (that’s the BTU input of the heater). So the Jandy LXi250N heater is has an input capacity of 250,000 BTU per hour and an efficiency of 88%. This means that 88% of the gas the heater burns is turned into heat in your pool water. So 88% of 250,000 is 220,000 BTU and this is the figure you need to help you work out which heater will do the best job for your pool.

Generally, the more efficient a pool heater is, the higher its price will be. Will the higher efficiency outweigh the higher initial cost? In some cases it probably will but in others it won’t. For instance, the Jandy Hi-E2 is rated at 95% efficiency but is three times the price of an average 84% to 88% efficiency unit. It is also very well made but the cost is hard for the average pool owner to justify. For the “average” pool you will most likely be looking at around 85% efficiency and roughly \$1,800.

It is usually a good idea to go for  a heater which has more capacity (BTU output) than you actually need because there is very little, if any, difference in the overall running cost. A larger unit will generally burn about the same amount of gas to give you the same temperature pool but will do it in less time. In fact, the wear and tear on a bigger heater is usually less than on a small heater but it is doing less work to achieve the same result.