In most instances, the coil of an existing cylinder will almost certainly be too small. This will result in longer cylinder reheat times at the lower water flow temperatures from a heat pump. Therefore, often a new hot water cylinder is needed instead of using an existing cylinder with a heat pump.
Grant UK supply a range of efficient hot water storage solutions which include cylinder models that are compatible with air source heat pumps. These cylinders feature a larger internal coil to reduce reheat times which will complement the air source heat pump's operation.
Read more about Grant's hot water cylinder range.