Air to air heating

An air-air heat pump is rarely recommended for vicarages. Vicarages usually already have water heating with a better heat distribution and a corresponding comfort installed. The recommended solution is to keep the water heating, based on renewable energy or district heating.

Air-air heat pumps can be installed temporarily in buildings heated by oil or gas, if it will take several years before it is practical or economically feasible to scrap the oil-fired boiler and connect the heating system to district heat or renewable energy. An air-air heat pump can be a supplement to the existing heat supply in the transition period, contributing with more environmentally friendly and possibly cheaper heat. How much oil or gas consumption can be replaced with heat from the air-air heat pump depends on the vicarage’s size and layout.

Which buildings are suitable?

An air-air heat pump is especially suitable in homes with large connected rooms, such as living rooms or a kitchen and dining room in open connection with each other, where hot air is easily carried around. In homes with many small spaces, heating every room satisfactorily with the heat pump alone will not be possible. In some cases, installing two heat pumps or a heat pump with two indoor units can be a good solution.


The purpose of the air-air heat pump is to reduce the consumption of oil or gas, so the ideal location depends on how the house is used. The heat pump’s indoor unit should be placed in the section of the building, which normally has the largest heat consumption. This could be a large living room or kitchen-dining room area.

Outdoor unit placement must be carefully considered, as there are both aesthetic considerations and noise limits to comply with. It is rarely a good idea to place the outdoor unit outside the bedroom window or next to the patio. Regarding neighbours, the Danish Environmental Protection Agency’s has noise limits, but the municipality may choose to impose other limits as well.

It is important that the outdoor unit is placed in the open air, to ensure a good supply of fresh air. Attics or similar places are generally not recommended. If a foreclosure is built for the outdoor unit, it must be very open. If sufficient ventilation isn’t ensured, energy consumption will be unnecessarily large.

The indoor and outdoor units can in principle be positioned at a certain distance from each other but to obtain the best operating economy the piping must be relatively short and well insulated.


An air-air heat pump provides heat at 50 to 60 øre pr kWh heat, if the electricity price is approximately 2.10 kr. per kWh. If oil is the existing heating source, the cost is typically 1.00 to 1.35 kr. per kWh, depending on boiler efficiency and the current oil price.

In a large vicarage heated with oil, an air-air heat pump in suitable conditions can reduce oil consumption by approximately 1,000 litres per year, representing a savings of 5000-6000 kr. annually. With an investment of 15.000 to 20.000 kr., the payback time is 3-4 years.