Heating your pool seems simple, you put a heater on your system and you get hot water. But then the questions come up, what kind of heater do I get, gas, electric, or solar? What size heater do I need? All important questions and all the answers will be different for everyone. So let’s start with the types of heater and their advantages and disadvantages.
Gas heaters come in two different styles; natural gas, and propane. If you have natural gas available that is the best option because propane heaters are considerably more expensive than natural gas to operate. Gas heat’s advantage is that it will heat your pool quickly. When I say quickly that is relative to the other types of pool heaters available. Depending on the size of your pool and the size of heater you have a gas heater can heat your pool in several hours. Another advantage a gas heater has is that it will heat the pool all year long and this is important if you have an indoor pool you plan on using all year. Gas heaters can be placed indoors or outdoors, however since they involve fire they have to be properly vented both indoors and outdoors. Also because of the fire and explosive nature of the fuel and carbon monoxide they produce gas heaters require multiple building permits in order to be safely installed to code. So to review good side of gas heaters: They heat the pool quickly, they heat the pool all year long, and they can be placed indoors. On the down side: They are expensive to operate when compared to other types of heaters, gas heaters require three permits in order to be installed according to the building code.
Heat pumps are very energy efficient and cost considerably less to operate than a gas heater, however they take longer to heat the water than gas heaters. When heating a pool with a heat pump you should allow at least 12 hours or more to heat the pool to the desired temperature depending on the starting temperature. With a heat pump the colder the water is the longer it will take to heat the pool. Heat pumps however do not require a building permit like gas heaters. Heat pumps cannot be placed inside a building; they can only be placed outside, but heat pumps don’t emit CO2 into the environment. Heat pumps can only convert heat from the air from a certain outdoor ambient air temperature, with Aqua Comfort Heat Pumps Aegean Pools sells, the heat pump can convert down to 40° ambient air temperature. Aqua Comfort also offers a line of heat pumps that will not only heat your pool but if your pool water gets very hot during the summer they can cool your pool water! To review the good side of heat pumps: They are considerably less expensive to operate than a gas heater and much easier on the environment than a gas heater. Aqua Comfort heat pumps will heat down to 40° ambient air temperature. If you select the heat/cool model you can not only heat your pool with the heat pump you can also cool the water, gas heaters cannot do that. Heat pumps do not require a building permit to install like a gas heater. On the down side: They take longer to heat the pool water than a gas heater and will not heat the pool all year round. They also cannot be put inside a building.
Solar heat comes in several versions; solar blankets, solar panels, solar pods. Regardless of the type of heating system you decide to employ it is recommended that you use a solar blanket. Solar blankets look like bubble wrap packing material but the plastic is much thicker, eight to twelve mils thick depending on the model you choose, and usually tinted a deep blue color. Solar blankets have two functions; first they collect radiant heat from the sun and transfer that heat to the pool water. This will reduce your dependence on any other type of heating system you may be using reducing the cost to operate that system. Second, they trap heat in the pool by stopping evaporation. When you see steam coming off the surface of your pool what you are seeing is the heat escaping from the water. The solar blanket blocks that process. If you want to try and heat your pool without spending thousands of dollars a solar blanket is your best option. If you decide to employ a solar blanket you will also want to invest in a solar reel. While solar blankets are not heavy they are bulky and un-wieldy to handle. If you don’t have a reel for the blanket you will end up dragging this hulking mass across the deck. When that happens you will puncture holes in the air bubbles of the blanket, when that happens you destroy the heating capability of the blanket and make it much more difficult to handle. The solar reel will stop you from dragging the blanket across the deck extending the life of the blanket. In addition it will make moving the blanket around simpler and less messy. If you use a solar blanket you don’t want to leave the blanket on the pool to the point the temperature goes over 95°, keep in mind the hotter the water is the faster algae and bacteria will grow. Also, the solar blanket creates a shaded environment which algae love and helps enhance its growth. So when you get up to temperature take the blanket off the pool and store it out of the sun. The good side of solar blankets: The initial investment is substantially less expensive than conventional heaters. There is no cost to operate because it uses heat from the sun. It keeps the heat in the pool as well; no other heating system does that. On the down side: Solar blankets can be un-wieldy to handle without a solar reel. If you don’t get at least six hours of sun on your pool the blanket may not warm the pool up to your desired temperature. If you leave the blanket on too long it can promote algae growth.
Solar panels/pods come in all kind of styles roof mount, rack mount, and ground mount. In ground pools usually use panels and above ground pools usually use pods. If you are going to go with roof mount solar you should consider having it professionally installed to protect your roof from leaking. However there are do it yourself solar kits if you feel comfortable working in that environment. For this type of solar heater to be effective you have to have correct exposure to the sun on your roof and sufficient length of exposure, otherwise your pool will not warm significantly. The great thing about solar heat is that it does not cost anything to operate. Another nice feature is when the pool water gets hot during the summer you can run the water through the panels at night and it will lower the water temperature several degrees. Now granted the heat/cool heat pump will lower your water temperature far lower than the solar panels will but, you will get some temperature reduction from the panels being used at night. Most solar panels are flat and go on the roof of a structure. Above ground pool solar pods are usually modular, compact, fit in a very small area and are easy to connect to the filter system. The good side of solar panels/pods: The only cost you have is the equipment once you have made the investment the panels begin paying you back, the longer you have them the more the cost of operation goes down. Solar panels on the roof of a structure will drop the water temperature several degrees if you run them at night. The down side of solar panels: Professionally installed panels can cost thousands of dollars. Solar panels are definitely not an attractive feature on the roof. Solar panels will not work if you do not get sufficient exposure to the sun. Solar panels will not heat the pool year round, you will still need a gas heater if you want to warm you pool water all year.
One of the most important things you must know when you are trying to determine what size of a heater or solar system will be right for your pool is your pool’s surface area. Surface area is important to determine heat loss. The heating system you are considering has to be able to overcome that heat loss. Time for some geometry:
Here are the examples for all three pool types:
For a kidney shaped pool that was 36’ long 16’ wide at the shallow end and 18’ wide at the deep end the formula would look like this:
Surface Area= (16 + 18) x 36 x .45 the answer would be 550.8 square feet.
For a round pool that is 24’ round the formula would look like this:
Surface Area= 12 x 12 s 3.14 the answer would be 452.16 square feet.
For a rectangular pool that is 20 x 40 the formula would look like this:
Surface Area= 20 x 40 the answer would be 800 square feet.
So if we are going to determine what size gas heater we would need for this pool we will need a chart from the heater manufacture showing the maximum square footage that the heater will handle like the one below:
So in our 16/18 x 36 kidney pool we would need to install at least a H200 model heater. If you want to go larger it is not a problem, it will just heat the pool more quickly. However, if you go too small your heater will struggle to maintain the desired temperature and you will wear it out faster and spend lots of money on fuel to heat the pool. So determine what size heater you need for you pool them go up at least one size for efficiency sake.
To size an Aqua Comfort heat pump consider that bigger is always better to achieve quick heating. The largest heat pump is a 175k btu unit. The most popular is a 155k btu unit, this unit will usually handle pools up to 800 square feet.
To size a solar blanket you will buy it based on the size of your pool. In our kidney shaped pool example you would want a cover size 18 x 36. When you lay the blanket on top of the pool water you will leave it on the water for a day or two to allow the vinyl to shrink slightly in the sun, then you will trim it with scissors to the shape of your pool.
For solar panels/pods you should consult with the specific manufacture for sizing requirements.
This is a pretty comprehensive review of swimming pool heaters, however there are usually questions and as we are not in an actual classroom you cannot raise your hand to ask a questions, if you do have a question please feel free to contact me or visit our retail store to have your question answered by one of our pool experts.
We have one more class this year so don’t be late you won’t want to miss a minute of class.