ELECTRIC HEATING IN CHURCHES
About a half of Denmark's churches are heated by electric heating. Electric heating is easy to distribute in the entire church building, doesn’t imply a particularly visible heating system, floors don’t have to be dug and other major interventions in the church aren’t necessary when using electric heating. This explains the widespread use of electric heating. Also, electric heating is easy to control and the heat-up is generally fast and accurate.
Heat distribution with electric heating
Ideal heat distribution is achieved when heaters are installed underneath the benches (as tubes or with radiant heat) and along the outer walls (typically as electric heaters or panels) in both the church nave and balconies.
Electric heating can also be supplied with a heating surface in a calorifier (air heat), but this implies poorer heat distribution and bigger energy consumption.
Electric heating to periodically heated churches, but not to permanent heated churches
Periodically heated churches without base heat, achieve the lowest heating costs with electric heating. Electric heating can be controlled very precisely and can be switched off when the church is not in use without the risk of frost damage to the heating system. Energy consumption can thus be very low, which outweighs that electric heating is more expensive than other forms of heat per energy unit.
Energy consumption is relatively high if a church has a base temperature and/or many church services. Electric heating is relatively expensive. If there are more than one or two church services on average per week, it should be considered whether there are good and cheap alternatives to electric heating.
Ideal heat distribution is achieved when heaters are installed underneath the benches.
Electric heating in combination with a heat pump?
In churches where base heat is necessary, combining electric heating and an air-air heat pump can be considered. The air-air heat pump cannot cover the entire energy consumption, but it can cover the base heat if it is dimensioned correctly. An electric heating system should then only be turned on when the church is heated for worship services. Heating up for worship services must be done quickly, both in regards to energy use and for the sake of preserving the church and its furnishings. This requires that the output of the heating system is very high - higher than an air-air heat pump alone.
Is electric heating in the church sustainable?
A growing share of electricity consumption in Denmark is based on renewable energy, especially wind energy. However, there are still plants that produce electricity from coal or natural gas, and they primarily produce electricity during peak load (the time of day when our total consumption is greater), and when there is no wind. The ratio of "green energy" and "black energy" is not a constant value.
During the day on weekdays and especially around dinner time, there is typically a large share of "black power" because consumption is high and power plants must contribute a lot. Conversely, nights have a larger share of "green power" because consumption is low and power plants shut down.
If heat is controlled optimally in the periodically heated churches, heating mainly takes place in the night, i.e. Sunday night, when the highest proportion of "green power" is in power grid. In this way, electric heating in churches is considered more sustainable than electric heating in general.
With a price of about 2.10 kr. per kWh, electric heating is an expensive source of heat. Electric heating, however, can be controlled quite precisely resulting in no "waste". Therefore, electric heating will often be significantly cheaper in periodically heated churches compared to oil-based heating.
A medieval church in eastern Jutland was heated using oil-fired boilers and calorifiers. The church has a volume of about 600 cubic meters and is heated for about 35 church services per year. Oil consumption is high, averaging about 4,500 litres annually. The entire heating system was replaced, establishing electric heating instead. At the same time, a new user-friendly management system was installed, so the heat can be precisely controlled.
The total savings is about 33,000 kr. annually. With an investment of approximately 650,000 kr. the payback time is around 20 years. The repayment period is actually somewhat shorter, since the old heating system probably would have needed significant maintenance and repair in the time period, had it been retained. Finally, the comfort of the church has significantly improved.
Read more (in Danish)
The Ministry of Ecclesiastical Affairs heat Circular: https://www.retsinformation.dk/Forms/R0710.aspx?id=72628