A retrofit heat pump usually means a heat pump which can be installed for an existing geyser (or an existing cylinder). This way, you can just buy a heat pump and save the money for a water storage tank.
A retrofit heat pump should be:
- split type. A monobloc heat pump has an integrated water tank with it, which is not needed at all. While a retrofit heat pump is just a heat pump main unit, and your existing geyser act as its water tank.
- with a built-in circulator water pump. A retrofit heat pump is heating water when water is circulating between the heat pump and the geyser. The circulator water pump is the device making water circulate. A built-in circulator water pump is the best choice, for a exterior one is too complicated for users and installers.
- sealed refrigerant circuit. Some domestic heat pumps heat water through refrigerant coils in water, which is not the right way for retrofit heat pump. To put refrigerant coils into your own geyser by yourself is almost a “mission impossible”.
Now that we have the right heat pumps, then how about the right models?
- If your geyser is 100~300 liters, a retrofit heat pump with the input power of about 1KW will be OK;
- If your geyser is 300~500 liters, 1.5~2KW will be needed.
The installation is pretty easy. The retrofit heat pump is mounted on the outside wall like a outdoor unit of an air-conditioner. Connect the heat pump to your geyser by water pipes. There are some main points:
- Make sure water is able to circulate smoothly.
- You need to insert a thermostat into your geyser for the heat pump to control water temperature. The thermostat is supplied together with the retrofit heat pump usually.
- Add a filter (Y-style, e.g.) at the cold-water-in pipe. Impurities in water will block the heat exchanger and damage your heat pump. If necessary, add a water softener as well.
An air source heat pump for water heating means you can save up to 75% on your electric bills; a retrofit air source heat pump save even more–it save your geyser (or cylinder) money, too.