The Off Switch#
The best way to be sure you aren’t using any gas or electricity for heating is to turn the heating completely off. You don’t want to disable the heating if it will lose you room hires or make people so cold they bring in space heaters, but in the current climate crisis, some communities will be receptive to the old British tradition of heating only from October to May.
It’s possible your system isn’t coming on in the summer anyway, but it might be:
Radiators are a popular way of warming croissants and drying clothes in all seasons - press an override button and whack the thermostat to 26C.
Even if no one touches the controls, if the diary has heating set in it, your system may be warming up the boilers just in case. In one church with two services a week, we found a brand new system was using 28 kWh even without heating any radiators, at a cost of around £9 a month (September 2022 prices).
You might want to check whether there will be any problems with your boiler or other parts of the system if you do turn everything off for a few months.
The most likely issues are with pumps and motorised valves seizing up. The older they are, the more likely this will happen. If you are concerned about this, the right thing to do is go turn the system on every so often and make sure the pumps and valves moved. Leaving the boilers on isn’t a guarantee that they will operate so it doesn’t necessarily help.
Modern boilers turn themselves on periodically for maintenance checks, but this doesn’t appear to do anything but flash an error code that you’re unlikely to notice until autumn anyway. We’ve checked with Worcester Bosch about a recent boiler installation, and they are unconcerned; turning the boiler off won’t void the warranty.
We’ve seen old boilers failing to ignite if they haven’t been used for a while, but don’t know if that’s normal.
A warning, though: some service providers find this question puzzling. Manufacturers are the authorities on this and should be happy to answer this kind of question.
What if the temperature drops suddenly?
In stone buildings or buildings that are well insulated, rapid internal temperature changes are physically impossible. Remember that in the summer, the walls and other surfaces will be relatively warm. The building will be a steady and comfortable temperature given the right clothing, as long as it doesn’t have a cold wind blowing through it at the time.