Changes in Heating and Ventilation for Churches During COVID-19

Old man praying in a church


The development of the corona pandemic is dynamic and forces us to react more and more. Currently, existing regulations are constantly being reviewed based on the requirements of the state and the federal government if they change. The regional church compiles all current information, hints, and suggestions for dealing with Corona and updates them continuously.

To ensure maximum health protection, we also have to rethink our usual ventilation and heating behavior in the cold season and adopt new technologies. The aim is to find ways to operate the existing heating systems in the churches in such a way that the celebration of church services is also possible in winter.


  • During the service, the church should not be ventilated if this results in increased air movements. This also includes doors and windows. After the service should be ventilated briefly, but intensively. Ventilation is best done by transverse ventilation through the windows and doors. If this is not possible, the doors should be opened wide for a few minutes. It is important to control the relative humidity during ventilation. If possible, the relative humidity in the church should be between 40 and 60%. The aerosol droplets shrink more if the air is too dry (evaporation) and therefore remain suspended for longer. Too dry air (< 40%) can also lead to damage to the inventory. A simple moisture meter (from the hardware store) can give a clue. If the relative humidity drops too much, moisture may have to be supplied to the room (e.g. wipe damp).
  • Automatic ventilation (e.g. window sashes or similar) also with detection of the outdoor and indoor climate can be operated outside the service. Here, attention should be paid to humidity-controlled ventilation control. It is therefore important to carry out technical monitoring of the entire system. During the service, the facilities should be switched off.


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Notes on the different types of heating

  • Except for heated seat cushions, underfloor heating, and radiant heating, the heating systems should be switched off at least 30 minutes before the start of use to avoid air movements during the service. They are not to be put back into operation until after the event. The limited operation of the systems may result in certain losses in comfort.
  • The desired room temperature should be reached before the start of the event. This presupposes that sufficiently long is preheated so that the external components are also heated. The warmer the outer walls, the lower the draughts. However, it should not be overheated “in stock”, because: The higher the room temperature, the higher the energy consumption. In addition, the relative humidity decreases with increasing temperature.
  • Circulating air heaters (with hot air ducts and central heat generators or individual “thermal stations”): At least 30 minutes before the service, the recirculation heater must be switched off completely. For the air filters, both in ventilation systems and in-floor shafts, there is a risk of contamination. The filters should not be vacuumed. For safety reasons, the protection of maintenance personnel should be ensured by gloves, mouth-nose protection, goggles, and protective suit when changing filters. Due to the high effort, the conversion to higher filter qualities for recirculating air heaters is technically difficult and financially impossible. In addition, further distribution of the viruses cannot be ruled out. To avoid heat loss, doors must be kept closed. An increase in the proportion of outside air cannot be done arbitrarily with warm air heaters, as there is a risk that the relative humidity will drop too much.
  • Convectors (radiators installed in the room or in shafts, which only introduce heat into the room in individual places): At least 30 minutes before the service, the heating must be switched off completely. Since heating convectors cool down slowly, air movements will decrease, but will not end abruptly.
  • Underfloor heating: Underfloor heating systems can be operated continuously at a constant base temperature. This also applies to systems that are installed in some areas.
  • Seat and footstool heaters: Seat and footstool heaters, which are used for seat temperature control, should be operated in such a way that the bench areas are heated before the start of the service. At least 30 minutes before the service, the heating must be switched off completely.
  • Windowsill heaters: Window sill heaters are used to reduce sloping cold air flows along with the cool windows and thus air movements in the room. They can be operated especially at low outside temperatures if they can be switched independently.
  • Electrically heated seat cushions: can be operated
  • Radiant heaters: Radiant heating (in ceilings or walls). The systems can be used for basic temperature control

Situation in meetinghouses

  • Air circulation by hot air or convection heaters, etc. should be avoided and the systems should be switched off at least 30 minutes before the start of use. The rooms should be heated evenly. Since the components and surfaces are preheated overall, the cold air waste and air movements will be lower due to temperature differences.
  • The usual temperature reductions as an energy-saving measure (night reduction, max. 5 K) are possible but should be completed in good time before the start of use, taking into account the local conditions.
  • Existing ventilation systems should only be operated if they have been regularly maintained and meet the hygienic requirements. During operation, care must be taken to ensure that only fresh air is blown into the room.
  • Depending on the equipment of the room, e.g. with wooden fittings, organs, etc., sufficient humidity must also be ensured. If there are draughts due to leaking external components, it should be checked whether provisional sealing measures are possible. However, it should be noted that a sufficient ventilation possibility in the rooms is maintained.
  • Openings to cooler zones (foyer, chair storage, kitchenette) should remain closed. For longer events, ventilation breaks should be made, e.g. after 30 to 45 minutes (depending on the size of the room, the distance of the people, and the number of people in the room).