Swimming Pool Blog
by Rob Cox September 11, 2019
DIY Installation of a Pool Heat Pump
You want to add some cheap heat to your swimming pool? Pull the heat out of the surrounding air! You can save thousands of dollars by Purchasing, Placing and Plumbing your own heat pump, and then hiring an electrician to wire it up.
Pool heat pumps, popular now for over 30 years in Florida, have advanced to levels of efficiency to operate with high output, even when outdoor temperatures are cool.
The installation (at least most of it) is a real simple affair. The placement and plumbing can be easily done by any homeowner, but the electrical hook-up may be best left to an electrician.
Electric heat pumps need a lot of amperage to power the fan and compressor, and there's one thing I know about electricity, it's not the volts that'll kill ya, it's the amps! Heat pumps need a 30-50 amp breaker, and heavy gauge wire to carry the current.
We'll discuss some guidelines for electrical hookup later, now let's discuss purchasing, placement and plumbing for a pool heat pump.
Purchasing a Pool Heat Pump
When you consider the wide array of heat pump models available, from over a dozen manufacturers, choosing just one can be difficult. Features such as digital display and self-diagnostics are common, as are Scroll compressors, titanium heat exchanger or the ability to heat or cool the water.
Most importantly however, would be the size of the heater. Pool heat pumps are rated by the amount of BTUs that they generate, the smallest being around 50,000 BTU, up to 150,000 BTUs. Installing a heat pump that is too small can cause it to become overworked, or not keep the pool as warm as you like, or take long periods of time to heat up to temperature.
50-75K BTU heat pumps are best for aboveground pools, and 95-140K BTU heat pumps are better for inground pools. It bears repeating, much like filter size, you'll never regret having a larger heater when cool and rainy weather comes around.
Placement of a Pool Heat Pump
The heat pump is usually placed next to the pump and filter, but if you have a need to place it further away, you can run as much pipe and wire to it as you need. The best location will be shielded from heavy winds and water from roof run-off or sprinklers. Heat pumps need to have adequate air space all around the unit, at least 2 ft. on all sides, with 4 ft on the front for access, in case future repairs are needed. It should have clear sky above it, without eaves or overhanging trees blocking the exhaust air. Placing the unit in an area of direct sunlight will increase efficiency, by warming the area around the heater.
Heat pumps are heavy (250-350 lbs) and the base should be very solid, either a concrete pad, or a substantial plastic AC unit pad can be used. You can also build a level 4x4 ft. frame with 6x6 in. lumber and fill it full of gravel. If the area slopes downward behind the equipment pad, be sure to stake in your wood frame, or pour footers for an A/C pad or concrete pad.
If you have nearby dryer vents or furnace vents, you can recycle some of your home's lost heat with a pool heat pump drawing in the warm air, but keep the vents at least 48" from the heat pump.
Plumbing of a Pool Heat Pump
Heat pumps are very easy to plumb, just one pipe going in, and one pipe coming out. You will need some basic PVC plumbing fittings, 90's, 45's and couplings - plus several feet of pipe, a hacksaw, and PVC glue and primer. Union connections are standard equipment with most heat pumps, and allow you to drain the heat pump, for winterizing or repair. Most heat pump unions are 2" or 1.5", so you can connect either size PVC pipe.
Find a spot on the return line, on the pipe exiting the filter and carrying water back to the pool. The spot you cut on the pipe (with the hacksaw) should be before any chlorinator, salt system or purifier unit. Cut out a few inches of pipe, and with the use of the PVC fittings and the pipe (flexible or rigid Schedule 40 PVC pipe), run the pipe in and out of the heat pump, priming and gluing all fittings securely.
To reduce resistance and turbulences, the best installation will make use of as few 90's elbows as possible, and keep straight runs where possible. Substitute sweep elbows instead of standard elbows to reduce restriction by over 50%. Plumbing in 2 inch PVC pipe also reduces restriction. To reduce turbulence, run 6-8" of straight pipe directly out of the heat pump, before the water encounters the first turn (90 or 45 elbow).
Here are some pictures of a few installations of pool heat pumps.
Wiring of a Pool Heat Pump
As mentioned earlier, wiring a heat pump does require a lot of amperage, and mistakes in wiring could be hazardous or fatal. With that disclaimer out of the way, here are some guidelines for wiring a pool heat pump. Please consult the owner's manual or installation instructions for specific information.
If your pool has a 100 amp sub-panel by the pool, which many inground pools do, it's possible that you have enough leftover ampacity available, to add a 30 or 40 amp breaker to the sub panel that's already there. If so, the electrical installation is made much simpler. You only need the proper sized breaker and wire, and sturdy conduit and connectors to run from the sub panel to the heat pump.
If your sub-panel is full-up, or you have no sub-panel, just a time clock for your pool pump - then the job becomes more expensive. The cost to bring power to the heat pump will vary on the distance to the home main breaker panel, and of course you need to have enough available amps in the home main panel to add a new breaker of 30-50 amps. An experienced electrician always has a way to make it work.
As stated above, you could install the heat pump in another location, closer to the home's main breaker panel, and dig a trench to bury the pipes in the ground, or insulate them to prevent heat loss. This will reduce the electrical cost, but raise the plumbing cost. The average heat pump electrician's expense is about $500, more or less.
In addition to bringing enough power to your heat pump to power the unit in durable conduit, your electrician should also pigtail the heat pump to the bonding wire grid.
~ Bypass those outrageous quotes you've been given for a complete pool heat pump installation, save 25% or more by Purchasing, Placing and Plumbing your own heat pump, then hire a local electrician to hook up the power and bonding wire.
Choose from 7 Great Models by AquaCal, Aqua Pro, Hayward and Pentair.