Pool heating

For a typical 8 × 4 m covered pool held at 28 °C, a heat pump costs roughly $2–$3 a day through the shoulder season and less in mid-summer. The same pool with no cover costs three to four times that, and the same pool on an electric element costs about five times that. Use the calculator above with your own pool size and power price — it is the honest way to answer this, because pool size, cover and target temperature change the answer far more than the brand of unit does.

From cold, allow two to four days for a normal domestic pool — a heat pump raises the whole body of water gradually. After that first heat-up it only has to replace what the pool loses overnight, which is a much smaller load. This is why pool heat pumps are left running through the season rather than switched on the morning you want to swim.

Yes, substantially. A gas boiler burns fuel to make heat and is around 90% efficient, so you always get slightly less heat than you paid for. A heat pump moves heat that is already in the air, and returns about five units of heat for every one unit of electricity. On current Auckland prices that works out roughly two and a half times cheaper to run, and there is no daily gas connection charge.

For the heating to be cost-effective, yes. Most of the heat in a pool leaves through the surface by evaporation, and a cover stops about three quarters of it. A cover typically cuts running cost by two thirds and allows a smaller unit to be fitted.

Surface area matters more than depth, because heat leaves through the surface. As a rough guide: up to about 65 m² a 15 kW unit, up to 80 m² an 18 kW, up to 110 m² a 24 kW. We can find the perfect unit to heat your pool. Exposure to wind, shade, whether there is a wet edge, and the temperature you want all shift it. The calculator on this page will get you close.

Not the same unit at the same time, but the same idea can. If you are putting in hydronic underfloor heating, one correctly specified heat pump can run the underfloor through winter and the pool through summer — the two demands barely overlap in Auckland. That is one of the neatest things you can do on a new build, and we do a lot of them. See our pool and underfloor heating page.

The residential units run at about 53–56 dB(A) at three metres, which is roughly a conversation at the other end of a room. Siting matters more than the rating — against a boundary fence under a neighbour's bedroom window is a bad idea whatever the number says. We will tell you where it should go.

Yes, and it is one of the most common jobs we do. The pipework already runs to the plant area and the pool already has a filtration circuit, so the swap is usually straightforward: remove the gas heater, set the heat pump on a level base, connect flow and return, run the electrical, and commission. Most are done in a day. The gas line is capped off and certified by a licensed gasfitter.

It will run, but heating an outdoor pool through an Auckland winter is expensive with any heat source, because the air is cold and the pool loses heat all night. Heat pumps become less efficient as the air cools. The usual use is season extension — swimming from about September through to May — rather than year-round outdoor swimming. Indoor or fully enclosed pools are assessed separately.

For a straight heat pump installation on an existing pool, normally no. The electrical work must be done and certified by a registered electrician, and if we are removing gas the decommissioning must be done by a registered gasfitter. New pools and new plant rooms may have consent requirements of their own — your pool builder will usually be handling that.

Yes. The heat exchangers in the units we fit are made for pool water, including salt chlorinated pools. Water chemistry matters: a pool badly out of balance will damage a heat exchanger, and that is not covered by warranty.

Choose the unit and the location with the coast in mind: keep it out of direct salt spray where possible, rinse the casing down occasionally, and keep up the annual service. We will tell you if a position is likely to shorten the life of the unit.

With balanced water and an annual service, expect fifteen years or more from a quality pool heat pump. The main causes of early failure are poor water chemistry, lack of servicing, and poor airflow around the unit.

Yes. We service pool heating across Auckland regardless of who put it in, including units well out of warranty. If it can be repaired economically we will tell you; if it is past it we will tell you that too. See servicing and repairs.

Yes. A small body of water is quicker and cheaper to heat and holds temperature well under a cover. The same units run at a higher spa output rating.