Free Heat For Your Swimming Pool

Using Waste Heat from

air-conditioning and refrigeration or heat pump.

Written By:  Scott Meenen of:
G&S MECHANICAL SERVICES of Maryland.

    When compared to the cost of running a natural gas, propane or oil fired pool heater, this system will win every time. When compared to the cost of installing and piping a conventional heater the costs are less..

    Performance: Depending on the size of your pool, the output of your a/c unit and the outdoor temperature, you can expect to pick up 1 to 3 degrees F per day and should extend the season by at least one month later and possibly two months earlier.
Cooling performance may not be very noticeable, but can make the difference on a hot day. Electrical consumption will be noticeably less, especially on hot days when it would be highest on an air cooled (conventional) system.

    Additional equipment: water to refrigerant heat exchanger for transferring heat from a/c system to pool water. Piping to run from pool filter system to water to refrigerant heat exchanger.
The Indoor coil should be changed to one that can accommodate a TEV (thermostatic expansion valve) if it doesn't already have one. This change will improve cooling performance and prevent coil icing when the pool water is cold. Pressure safety controls are mandatory in case of inevitable water flow failure or indoor coil icing.

    Costs: Basic system; where the pool filter is right next to the outdoor unit (straight air-conditioning only) and the indoor coil does not need to be changed in any way, existing unit already has pressure controls, compressor does not need a start kit (scroll compressors do not need start kits)  and no indoor work needs to be done.
$1200 US (within 20 miles of Washington dc. or Baltimore md.)

    Standard system; where the pool filter is right next to the outdoor unit (straight air-conditioning only),  the indoor coil must be changed to one that will accommodate a thermostatic expansion valve, pressure controls must be added and the unit requires a start kit
$1500 US (within 20 miles of Washington dc. or Baltimore md.)

    Indoor system; everything included in the Standard system where the pool filter is located in the basement or a vault near the indoor section and the outdoor unit is within 15 feet of the filter pump.
    In this system the heat exchanger will have to be supported from the ceiling or hung on a shelf and the water piping will be pvc pipe integrated into the filter system. Since these quarters are usually tight it will require more labor but system will not have to be drained in the winter.
Subtract $350 if the indoor coil does not have to be changed
$2100 US (within 20 miles of Washington dc. or Baltimore md.)

    Remote system; everything included in the indoor system but the pool filter is located over 50 feet from the outdoor unit because a trencher will have to be used to bury the pipes to bring filter water to the refrigerant heat exchanger or in some cases the refrigerant lines can be extended.
Subtract $350 if the indoor coil does not have to be changed
at least $2100 US (within 20 miles of Washington dc. or Baltimore md.)

Heat pump systems, systems over 4 tons, multiple systems and other modifications that require extra controls and piping will significantly add to the cost of the system.

Frequently asked Questions:
Q: how hot will my pool get?
A: Depending on the weather and the size of the pool in relation to the building and if a cover is used,  the pool can get as hot as the mid 90s but will loose heat so fast that it will be limited to the low 90s.

Q: What do I do I do in winter?
A: .The system will have to be drained in the usual manner and any additional piping will have to be drained or blown out with air. Indoor systems do not have to be drained.

Q: Will my air-conditioning work if my pool filter is not working?
A: No it will not but many commercial systems use devices called "cooling towers" that are similar in operation to this system and must be put in and out of service each year.

Q: My system is new, will this system hurt my present system or void any warranties?
A: This system when properly installed will improve the performance of your system but will most likely void any manufactures warranties. However except for the compressor most items are of nominal cost and can be fixed by us. If a compressor does fail in the warranty period we will most likely be able to get the warranty honored.

Q: My system is very old can this modification be done?
A: Yes, we have successfully modified a system that was 25+ years old and by changing the indoor coil we have improved the efficiency of the system to a level that is better than some new systems.

Q: I all ready have a gas or oil fired heater can this system help?
A: This system can help by saving money on fuel once the pool has reached a decent temperature. A fossil fueled system is nice to quickly bring the pool up to temperature but is a waste when the air-conditioning will provide free heat. We can set the controls so that the fueled heater will not run when the air-conditioning is running.

Q: I like a cold pool because I do laps and don't stay in very long?
A: This system is not for you!

Q: I have a very large pool will this system help?
A: If the pool is very large (surface area) and deep then this system will help but it will be limited in what it can do. You may need to consider adding solar collectors to boost the temperature of the pool.

Q: My system has given me lots of problems, will these problems go away?
A When we make the modifications, we will go over every inch of your system and any pre-existing problems can be corrected or discovered. One system we discovered that a metering device was left out since day 1 (25+ years), when we were done the system worked better than new.

For more information please contact us:

                 This text written by: Scott Meenen * G & S Mechanical