Checklist before you buy a heat pump

What type of heat extraction principle should you use?

The various methods for extracting energy with a heat pump are described in a separate section. Here is a brief summary.

Rock heat is the most common and gives a very stable heat source. One or several holes are drilled in the rock. One advantage to this method is that it has minimal impact on your garden. Read more about how a geothermal heat pump works.

Ground heating means that a long hose is buried in a loop about a metre below ground on your property. This method avoids drilling. On the other hand a large part of your property, which also has to be quite large, will need to be dug up.

Air heating is the heat extraction method that has the most simple installation because it does not require drilling or hoses being laid. When it is really cold outside this solution may reduce in efficiency.

Sizing

This is a very important phase in the heat pump installation. The heat pump system must:

A) Heat your house economically throughout the year.
B) Cope with the coldest days of the year.

A larger heat pump has a higher cost of investment, but the system will have lower running costs. By the same principle, a smaller heat pump has a lower cost of investment, but the system will have higher running costs. Correct sizing, therefore, will give the optimal balance between investment and operating costs.

Our heat pumps are available in a range of power outputs to satisfy every conceivable requirement.

How do you compare the performance promised by competing heat pumps?

Efficiency (COP = Coefficient Of Performance) is an expression used to describe the heat pump's capacity to produce heat in relation to the energy required to extract it. If a heat pump has COP 3 it means that it can produce three times more heat energy than the electrical energy it consumes. A unit of 1 kilowatt electricity results in 3 kilowatts of heat energy. In this example, your net exchange is two thirds.

But that is not the entire story. The efficiency is not constant. It varies with the outdoor temperature, or rather, with the difference between the indoor and outdoor temperatures. The greater the difference, that is the colder it is outside, the less efficient it will be.

When you compare the efficiency of different heat pumps, you should bear in mind that the efficiency is often audited in a specific operating condition, for example 0 °C/35 °C. That operating condition means that the incoming brine is at 0 °C and that the heat pump gives 35 °C to the heating system. The installation's circulation pumps are often not included in the efficiency calculation either. In other words, operating conditions of no interest to you as a consumer.

It is much more interesting to know what efficiency a heat pump can achieve averaged over the course of year, winter and spring, and day and night. This value is called annual efficiency. In this regard, the difference between different makes of heat pump is often very large.

The market for air heat pumps is quite complicated. The price differences are often very large, which reflects the different performances and functions. Be sure to check how effective the air heat pump is when it is really cold outdoors. A good heat pump should be able to retrieve energy from the air down to a temperature of -20 °C.

Remote control

Some heat pumps can be remote controlled using online tools. For example, if you are away traveling you can raise the temperature at home via the internet before you return.

Comfort cooling

Passive cooling
During hot summers it can be very pleasant with cooling indoors. A heat pump can fix this! By circulating the cool liquid in the loop, cooling is created at a cost corresponding to the energy consumption of a couple of light bulbs. This technique is called passive cooling and can be used with all heat pump solutions except for air heat pumps.

In most cases you need an extra accessory in the form of a cooling unit.