Though not a new phenomenon, its true to say that heatpumps have come of age in recent years. They are an extremely efficient way of heating a pool, and given certain parameters, can save a fortune in heating your pool. Everyone is looking for a cheaper way to heat their pool, and many dismiss heatpump because they don’t understand the way they work. Thats a mistake that be be costly! Don’t make the mistake yourself! Take the time to read this narrative, and get the facts, then make a decision whether its the way to go for you. If you want to save hundreds of pounds a year on fuel costs, read on! We have installed heatpumps for years for in our clients pools, and can speak from experience.

Heatpumps are a great green alternative because they use up to 80% less fossil fuel to produce the same amount of end heat output! Think what that means to the planet, less fossil fuel, less depletion of natural resources, less pollution, but heck, thats not the main reason your interested in the idea of a heatpump is it? Come on now, if your honest, the idea of saving a huge wad of money each and every year by reducing your pool cost is far more appealing than all those laudable and altruistic reasons isn’t it! That just what does happen though- you get a nice warm pool and save money while helping the planet! That’s got to be a double result!

Heatpumps used to be very expensive, so the payback time meant that they were not worth considering. Now however, because of worldwide popularity, more manufactures are producing units, and because of that, more people are buying them which has led to increased volume sales, more competition, and therefore lower prices, with far better products coming on the market. Fact is, a few years ago the only units generally available we £3-4,000, bulky, restricted to May to September use, with fairly low outputs of 8-12kw. Now we see new generation units being available at £1-3,000, with outputs of 10-30kw,. A word of caution is in order here though, all that glitters is not gold as they say! A lot of units we see advertised on the Internet and on-line shops are cheap rubbish that will fail and lead to heartache and disappointment- more on that later

There are many types of heatpump around today, some using heat sources as diverse as rivers, ponds, underground wells, and buried ground heat collecting coils to name but a few of the most popular types. Though all of these types have their use, cost of installation, plus the capital cost of the equipment makes them outside the viable use for most pool owners. For the sake of clarity, we will limit ourselves to discussing the type most frequently used in swimming pool applications, the air source heatpump, since these are simple to install, requiring nothing more that an electrical supply.

Can I use my Heat Pump All-Year-Round?

Basically, anytime you want to supply heat to your pool water, you should consider a heatpump. Of course, there are limitations. A heatpump works in essence, by removing available heat from the air and transferring It to the water. Although there are specialized units that will work efficiently at very low air temperatures, most heatpumps will be working at their optimum coefficient of performance (coeficient of performance, or C.O.P. for short, is the term used to express the efficiency of output of the heatpump), at ait temperatures of 15 degrees centigrade and above. As the air temperature gets lower, the COP. drops.also! To illustrate this consider the following: with an air temperature of 15 degrees and above, the COP will be about 5:1 that means, for every pound spent running the equipment, you will get £5 pounds worth of heat! Now thats great value. Now assume the air temperature has dropped to 10 degrees. Now the COP of asn average heatpump will have dropped to 3:1, so you are now getting £3 pounds worth of heat for every £1 spent. Still good value eh? But suppose the air temperature is only 5 degrees, what then? Well the heatpump will still be working, and still producing heat, but the COP will have dropped to perhaps only 2:1. While still giving you heat, the amount of heat you are getting from the heatpump, is probably not enough to overcome the heat loss from the pool, and so you may find the pool will never get warm enough, or worse, will not heat at all, as all you are doing is paying to put a small amount of heat into the water, that is sucked away by the pool structure and surface loss! Its a bit like trying to boil a kettle full of water with a single candle! You might make the water tepid given time and by lighting one candle as soon as the first one burns out, but you will never boil the water, no matter how much you spend buying candles!

Now however, try putting 50 lighted candles under the kettle, and suddenly you can get the water to boil! Get the point? Having the right number of candles to get enough heat to overcome the heatloss from the water results in putting more heat in the water than is being lost, causing the water temperature to rise and boil. Same principle applies to a heatpump. You will see many websites advertising that the units they are selling work down to zero degrees but beware, as that doesn’t mean your pool will be gaining any heat at those low temperatures. As you have seen, once the COP drops below a certain level, you may find you are running the unit and producing only enough heat to cover the heat loss, and so you are spending money running the unit for no gain! So does that mean you can’t heat your pool in the cooler weather such as we get in the British spring, autumn and winter seasons? No not at all-its just that you can’t do it with a heatpump (unless you are planning to spend a LOT of money on a specialist unit.)!

So how DO you heat the pool? Generally we use a conventional boiler in tandem with the heatpump, and we fit an air temperature sensing control. This lets the heatpump look after heating the pool until the air temperature drops below the preset 8 or 9 degrees, when the controller will drop out the heatpump and turn on the boiler. Also, many of the cheaper units for sale use inefficient gases that do not transfer the heat so well from the air to the water. Always check the type of gas being used, as some machines use gases that are banned under EU law. Sometimes you can buy a cheap machine, only to find that if it has a problem, it cant be repaired because the gas cant be replaced- not such a cheap buy then!