Buying a heat pumps - the checklist

  • Buying a heat pump

    There are various important questions before buying a heat pump. Here are three very essential questions to consider.

    Annual efficiency
    Most important is to rate the function over a complete calendar year – both the heat of summer and the cold of winter. 

    Hot water production
    A heat pump should not produce hot water that is hotter than the requirements. It is unnecessarily expensive. 

    Choosing the right installer
    A retailer should be authorised and well trained.  

  • Annual efficiency of the heat pump

    Auditing heat pumps efficiency with a particular measurement condition is not sufficient. 

    An air heat pump must function even when the outdoor conditions are bad and temperature is low. Otherwise the annual efficiency will be too low.

    As a buyer, you would, of course, like to know how effective a heat pump is?

    Most manufacturers choose to audit the COP in only one given operating situation. The heat pump's capacity produces heat in relation to the energy, required to extract and established in specific test conditions.

    If a certain heat pump has a COP 3, it means that in specific test conditions it can produce three times more energy than it consumes. In other words the net surplus is two thirds.

    Heat pump pays back when discussing efficiency. A high COP value measured in special conditions without all the system components - such as circulations pumps - can give high values. The measurement should not be tailored to the manufacturer's marketing plan. It should give you, the homeowner, a complete picture of how the heat pump works over time.

    Annual efficiency is a far more honest measurement of the heat pump efficiency. The whole year is taken into account, both the hot summer months and the cold winter periods.

    The size of the house, the geographic location and how many occupants are the factors which affect the overall picture.


  • Annual efficiency

    There are different measurements of a heat pump's efficiency. The most important is to rate the function over a complete calendar year – both the heat of summer and the cold of winter. This is called annual efficiency.

  • Hot water production

    A heat pump should not produce hot water that is hotter than is required. It is unnecessarily expensive.

  • Hot water production

    It is important to not focus on the level of heat of the hot water. The important thing is how quickly the new hot water can be produced in sufficient quantity for all the occupants of the house. 

    Approximately 20% or more of the heat pump energy output is used to produce hot water. It is important a correct requirement to be set for the sufficient amount of hot water of each occupant at home.

    Raising the hot tap water temperature from 55-60 °C to 65 °C is fine.  However, hot water is unnecessary. The annual efficiency is significantly reduced for each degree hotter than it is demanded. In addition, a heat pump which does not produce unnecessarily hot water will have a longer service life.

    For preventing the waiting period between the home occupants, it is important hot water to be produced faster and all that to be achieved at lowest possible cost.

    A good heat pump should produce sufficient hot water at the same time as maintaining high annual efficiency.



  • Choosing the right installer

    Installer must make a site evaluation of your house and the needs of the occupants. 

    How much heat and how much hot water must be produced? 

    This is called sizing. This is where it is determined what is required of the heat pump in order to obtain a good comfort combined with good operational costs.

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

    Your retailer should perform the following:

    • Optimal sizing; 
    • Good installation (Good function and installed neatly);
    • Accurate adjustment (The installation is adapted to the house needs in orderto create the best possible operating economy and comfort);
    • Good commissioning (A clear introduction to you as a user);
    • Any after service.

    Choose a retailer with care. Naturally, they must be fully trained, authorized and good advisors. These are demands required by Danfoss retailers. Ask for references from previous customers.


  • Installer

    Behind a good heat pump solution is a Danfoss retailer who accepts total responsibility.

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