Heat pump cylinders aren't a one-size-fits-all product. They come in 3 fundamentally different set-ups, and picking the wrong type for a property usually means an install that's harder, more expensive, or simple impossible. Here's how to tell them apart: 

Self-Contained Heat Pump Cylinders

This is the all-in-one option. There's no separate outdoor heat pump as the cylinder draw in surrounding air itself and uses it to heat the water, all from a single indoor unit. 

It's the simnplest install of the 3, and the obvious choice if there's nowhere sensible to site an outdoor unit, or the property just doesn't have the outdoor space for one. The trade-off is that it needs a reasonable volume of air around it to work efficiently, so it suits a utility room or plant space rather than a tight airing cupboard. Project CURV is a good example of these units. 

Integrated Heat Pump Cylinders

Here, the heat pump sits directly on top of the cylinder and draws its air from outside through insulated ducting, rather than from the room it's in. It's still a single unit to specify and install, and it tends to run quieter indoors rather than the self-contained model, since the noisiest part is drawing air from outside. 

The catch is the ducting itself as you need a viable route from the unit to an external wall or roof, so this option suits properties where that run is straightforward. The Dimplex Edel and Atlantic Calypso are both strong picks in this category. 

Built for a Separate Outdoor Heat Pump. 

This type is a cylinder only, designed to be heated by an air source heat pump site outside the building rather than one built into the unit. It's the right call when the outdoor heat pump is being specified separately or whether there is one on site, one going in as part of a wider retrofit, or one being fitted by another contrator. 

As this heat pump and cylinder are decoupled, you get more flexibility on siting and capacity. Just make sure the two are matched correctly before ordering. A good example of this is the Gledhill StainlessLite Plus Heat Pump. 

The Bottom Line 

There's no single "best" heat pump cylinder. Only the one that is right for your property. Self-contained wins where outdoor space is limited, integrated wins where a discreet ducted run is possible, and a seperate outdoor heat pump wins where flexibility on siting and capacity mattes most. 

Not sure what is right for you? Give us a call on 01934 253600 and we will do our best to advise!