How should I heat my pool?
There’s a lot of choices out there, and exactly what you choose hinges on a few things:
• What services are available, e.g. mains gas, LPG, oil, power supply
• Space: is there a suitable spot for a heat pump?
• What heating is already at the property? Is there spare capacity?
• Performance – how long is your client prepared to wait for the pool to get to temperature?
• Environment – Does your client want to minimise their carbon footprint?
Let’s run through a few basics for each option.
Using a boiler
You may come across a property where there’s already an existing boiler doing the house heating, and the customer is considering using it for the pool too. There’s no reason why they shouldn’t, but you do have to consider a few things that might make it less cost effective than they are expecting.
Is there capacity? Especially in newer homes, it may only be a small output boiler, and there just won’t be enough power to heat the pool as well.
Plumbing and control – you’ll need a heat exchanger such as Zodiac’s HeatLine or Uranus range, and you’ll need to zone off part of the heating system. Then you need a way to tell the boiler to come on. All this should be possible, but can add to costs.
What fuel are they using? Mains gas is still a cheaper alternative to LPG and oil. If your client is off-grid for gas, then a heat pump might be a better option and will certainly be cheaper to run. This applies if the client is looking at a dedicated pool boiler, plus they need a place to put it, and if it’s mains gas, it’ll need supply pipework.
The plus side to using a boiler is that the heat-up times are good. Running costs for mains gas are (comparatively!) low.
Using solar
Solar PV can make a big contribution to a property’s electricity usage, but can you use it to heat a pool? Not directly, but it’s certainly offsetting the running costs of, for example, an electric heater.
Solar thermal (flat panels or evacuated tubes) can be used via a heat exchanger, but their performance is seasonal – they won’t cope with the heating demand in winter or at the start and end of an extended season. It’s still a contribution, true, but you may be better placed investing in a really good quality slatted cover instead.
Direct electricity
An electric heater like Zodiac’s RedLine range works just like your kettle – it’s just a bigger version. It’s a simple way of heating a pool and heat-up times are as quick as they’re going to be – obviously this depends on the size of the pool and the power output of the heater. You have to ensure the power supply is up to it, though, and it’s expensive to run. Sometimes they are used as a back-up for other means of heating, such as…
Using a heat pump
Heat pumps used to be a bit mysterious. These days they are more widely accepted and understood, and an air source heat pump (ASHP) is a great way to heat a pool. Dedicated pool heat pumps do need to be properly sized for a pool, and so much depends on how much of the year your customer wants to swim for. It’s much harder work for a heat pump to heat a pool in winter!
Siting is hugely important for ASHPs, from both a noise and performance point of view. The right sized power supply is vital, too. A 3 phase power supply isn’t always necessary, but if it’s available, make use of it. Plenty of pool heat pumps are capable on single phase supplies, especially more modern modulating, inverter driven units. These are the most energy and cost efficient. For every kilowatt of energy a heat pump uses, it gives you up to four kW in return – this is what makes them a good choice both environmentally and financially.
Of course, when most people want to swim, the weather is fine and warm – and that’s when a heat pump works at its best. Mitigate any environmental concerns by considering insulated pools such as HeatForm, and using a high performance cover like Hydrodeck.
Ground source heat pumps are totally usable, but are a huge capital outlay – but if the build is still at the design stage, and this is an option for your customer, it’s well worth exploring.
