Air to air heating

An air-air heat pump is relatively rarely used in churches. It should never be the sole heating system, as the output is too small, but in a few cases, the air-air heat pumps can be a supplement to the primary heating. The purpose of the heat pump is then to keep a set base temperature in a church with low energy consumption and thus lower heating bills. This is especially relevant in churches heated by electric heating.

Location

It is important to consider a suitable location for both indoor unit and outdoor units, when considering whether to install air-air heat pumps in a church.

The indoor unit must be placed discreetly in the church. A "box” previously used for a calorifier air supply is a placement option or it can be installed as part of an organ loft. Theoretically, it can be built into a wooden ceiling, but such a location makes it difficult to get a suitable distribution of heat.

In principle, the outdoor unit can be positioned at a distance from the church, but for optimal economy, the piping must be relatively short and well insulated.

It is important that the outdoor unit is placed in the open air, to ensure a good supply of air. This may be an abolished grave in the cemetery or possibly in the church tower, if there are open hatches. 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.

Noise

Consider noise regarding the outdoor unit, both in relation to where it should be located and to the model to purchase – choose a low-noise model.

Economy

An air-air heat pump provides heat at 50 to 60 øre per kWh heat (considering the electricity price is approximately 2.10 kr. per. kWh). Compared with direct electric heating, there is thus a cost savings of 65 - 75%.

Air-air heat pumps can be relevant in churches heated by electricity, and which have high energy consumption for base heating (and where it is not possible or desirable to lower the base temperature in order to obtain energy savings).

There are very few examples of air-air heat pumps in churches, which makes it difficult to generalize about the total investment costs (incl. necessary changes in the church) or the running economy under different conditions.

Example

A village church on Funen spends about 35,000 kWh electricity per year on heating, of which 10,000 kWh are for base heating. The electric heating costs for the base heat are about 21,000 kr. annually. If an air-air heat pump is installed, the base heat would only cost 5000-6000 kr. annually. With savings of approximately 15,000 kr. annually, the payback time would be about 7 years, assuming an investment of approximately 100,000 kr.

If the base heat is lowered to 4 ° C an equivalent savings would be obtained.