Air Source Heat Pump Hot Water Cylinders – What’s it all about?

An air source heat pump hot water cylinder is basically a special kind of insulated water cylinder that does a fantastic job working hand in hand with an air source heat pump to give you all the domestic hot water you need for showers, baths and taps at home. Unlike your standard boiler tank, these heat pump cylinders often come with a bigger coil heat exchanger, allowing heat to transfer efficiently into the stored water at the lower primary flow temperatures commonly used by heat pumps

How Does a Heat Pump Hot Water Cylinder Actually Work?

An air source heat pump out in the garden sucks heat from the air and sends it off to your central heating circuit. Then that heated water makes its way through a coil inside the cylinder, where it transfers heat to your hot water without the two sets of water getting mixed up.

And that means your hot water is ready and waiting for you in your showers, baths and taps.

Why Do Heat Pump Cylinders Have Such Large Coils?

The thing is that air source heat pumps usually don’t run at as high a temperature as traditional gas or oil boilers. So a nice big coil helps get around this problem. It lets heat transfer go much better, gets the water in the cylinder hot more quickly and lets the heat pump work more efficiently in general.

What types of heat pump hot water cylinders are out there?

You can get heat pump cylinders of all sorts – from 200 litres up to pretty much anything you need or 1,500 litres or more. And there’s choice too; there are unvented cylinders that give you mains pressure hot water, or open vented cylinders, and there are twin-coil cylinders that work with a heat pump and another heat source like solar thermal, or even hot water from your boiler. Our full range of hot water cylinders for heat pumps are detailed here: Heat pump cylinders from 200 to 1,500 litres in volume for air source or ground source heat pumps

And then there are integrated heat pump water heaters – basically a heat pump and a tank in one. 

Choosing the right one – What to look out for

A few things to think about then: the cylinder size for you and your household, the heat exchanger’s performance, insulation, heat loss when idle, compatibility with your immersion heater, and of course, compatibility with your air source heat pump system.

The best heat pump cylinder for you is one that’s been carefully matched to your household’s hot water needs.