# Heating a pool



## timofleeds (Feb 11, 2014)

Hi, can any body share their experience of heating an inground pool with a heat pump. I am thinking of having one installed when I have my new pool built, it will be 8m x 4m with a pool blanket.
Regards Tim Patrick


----------



## davexf (Jan 26, 2009)

Hola, 

Whilst the idea seems to be good, a friend of mine said that getting out of a pool after September was too cold. This year we have had it a lot warmer but now the weather has cooled down, I would not like to get out of a pool into the much cooler air. 

You need to think of covering the pool with a structure that will allow you to get out into warmer air. 

Davexf


----------



## Pesky Wesky (May 10, 2009)

Or wear a wet suit


----------



## timofleeds (Feb 11, 2014)

Hi, thanks for your replies, getting out does not bother us.


----------



## Roystanley59 (Jul 14, 2019)

There are two forms of heat pump you can use air source or ground source


----------



## timofleeds (Feb 11, 2014)

I would be using an air source heat pump, do you have any experience of these Roystanley59?


----------



## Nomoss (Nov 25, 2016)

timofleeds said:


> I would be using an air source heat pump, do you have any experience of these Roystanley59?


I have lots of experience installing seawater source heat pumps on ships, and large and small yachts, as I used to sell them, and quite a lot on installing air source domestic systems, including in three of our own houses, where I installed supplementary heating systems (wood or pellet stoves) for the very cold weather.

They work extremely well and efficiently in seawater, as long as the water temperature is above about 5ºC, when the efficiency (COP) starts to fall rapidly with further decrease in temperature, but they still do produce more kW in heat than they consume in electricity as the water temperature falls lower, until they become useless.

The same applies roughly to air source heat pumps, but the big problem is that the outside coils (evaporator) start to ice up at ambient temperatures of somewhere around 8 to 10ºC, depending on the design of the coils and the air flow through them.

This causes the air flow through the coils to become blocked with ice, and the unit doesn't work any more. The solution is an automatic de-icing system, where the unit reverses to heat the outside coils until the ice has melted. This function may be set for a fixed period of time, which is usual, or the coils may have a device to sense that the ice has gone, which is less common and more expensive.

In icing conditions the unit will continually go into de-icing mode, which considerably decreases its efficiency, and it eventually becomes useless.

It may be OK if the unit is used only during the daytime, when the air temperature tends to be higher, but that may not be enough to heat a swimming pool.

Many units are advertised as having a reasonable COP at temperatures of -15º or lower, but there is usually very little air humidity below about -5ºC, so icing is not a problem. Installations in areas in N Europe which don't normally have winter temperatures below -10º will usually have enough air humidity to cause icing problems.

It's a case of "suck it and see", which is not good enough for the cash outlay involved, even though plenty of people will sell them and give all sorts of excuses when they don't work. A supplementary heating system in the form of a small electric heater should be considered. I think this is called a "boiler" in the UK, even though it doesn't boil anything.


----------



## timofleeds (Feb 11, 2014)

Hi Nomoss, thanks for your reply. I am in Southern Costa Blanca temperatures at night rarely go below 5deg . The pumps I am looking at have auto deicing built in. What do you advise is the minimum COP rating I should be looking for to have my pool at around 30degs
Regards Tim Patrick


----------



## NickZ (Jun 26, 2009)

COP is an efficiency rating. The better it is the less you'll spend in electrical bills. But usually higher COP ratings mean a more expensive unit. 

I'm curious why you aren't starting with a solar setup? Solar sized to handle the shoulder months. The add on system would only be needed when it's really cold.

You should find somebody local to size/design a system for you taking into account the local situation.


----------



## NickZ (Jun 26, 2009)

BTW if you do get a heat pump the smart thing would be to run it during the day while it's warm out. It'll use less power that way. Or at least wait for the sun to come up.


----------

