Do I have to switch off my central heating boiler when I go on holiday?

Instead of shutting down your boiler, activate the 'holiday' or ‘frost protection’ mode, or set the thermostat to its lowest setting.

Whether it’s to save money or to protect your home if anything goes wrong with your appliance, shutting down your boiler during your holiday is not necessarily a good idea. That's unless you still have an old model with a gas pilot light (flame), which consumes energy.

Why isn’t it a good idea to completely shut down your boiler?

1. No heat demand = no consumption

If you set your thermostat to a low temperature, your boiler won’t use energy to heat your home unless it really is very cold. 

The only exception: old boilers equipped with a pilot light (flame) which continually consume power. For these, it can be a good idea to turn them off if you go away in the summer.

2. No risk with a modern, well maintained boiler

In Brussels, gas boilers have to undergo mandatory maintenance every two years. They are also all fitted with overheating and overflow sensors that shut down the unit in the event of a problem.

3. For your comfort

When you get back, it’s nice to walk into a well-heated house. Depending on the insulation level of your home, the heat loss can vary quite significantly.

Modern thermostats for setting the temperature are the best tools to ensure optimal comfort. Some, for example, allow you to turn the heating back on the day before you return. But this means, of course, that you have to leave them switched on, and the boiler too!

4. To avoid breakdowns

Some boilers are set to run the pump with cold water for a few minutes after a few days. This consumes almost no electricity, and no gas or fuel oil at all, but it has the advantage of preventing the pump from getting jammed during a long shutdown period and being unable to restart when the heating period starts again... with the resulting repair costs.

For this automatic function to be active, of course the boiler still has to be connected to the mains.

To do before you go away

1. Set your thermostat to its lowest setting

If you have a room thermostat or perhaps a smart thermostat, you can very easily adjust the temperature to prevent the heating from running unnecessarily in your absence. It’s even possible to set the room temperature to increase a few hours before your return. 

A temperature of 14°C or possibly 12°C is high enough to prevent condensation.

2. If necessary, switch off the hot water production

If your boiler produces instant domestic hot water (without storage), you don’t have to do anything. However, if it has a hot water tank, your boiler will run needlessly to keep the water in the tank at the right temperature. You’re therefore better off shutting down the production of hot water.

If you have a separate water heater, remember to turn it off when you’re away.