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Just how much does the pilot light of a gas appliance consume exactly?

"Exactly" being the operative term as there lies the rub. Because, even though there are many estimates out there, not all pilot lights operate in the same way. Their flow rate may vary from one make to the next, and from one appliance to the next: instantaneous water heater, standalone gas-fired boiler or water heater.

Consulting different sources, you come across stated consumption levels ranging from 60 m³ a year, all the way up to 250 m³.

In order to work out how much it is costing you, the first thing to do is to convert the cubic metres into kilowatt-hours. The easiest way to do so is to multiply that number by 9.9.
So a pilot light uses anywhere from 594 (for 60 m³) up to 2475 kWh/year (for 250 m³).

The rate you pay depends on the supplier you have signed up with, but setting out from a rounded average price of 0.06 €/kWh, you are looking at anywhere between 35 and 148 € a year.

So how much does YOUR pilot light use?

To find out, we need to get organised

  • On a day with fine weather, where you can switch off the heating (set the thermostat to "frost protection mode" but leave the heater on).
  • If you have a water heater that is connected to the gas boiler, switch it off so the boiler does not activate – bear in mind you will not have any hot water for the day
  • If you have an instantaneous water heater, leave it as it is.
  • In the morning, read your gas counter, including the small red numbers after the decimal point. Make sure you do so at an exact time (e.g. 07:30am or 08:15am) to make things easier on yourself.
  • Do not use any hot water.
  • Wait for the day to end (do not use the gas cooker) or leave the house (or lunch out)…
  • At the end of the day, before making any changes whatsoever, read the gas meter again. Wait for the same fraction of an hour as the time when you took your first reading this morning (e.g. 05:30pm or 07:15pm) which will make doing the maths a lot easier.

Now then, time to work it. Here's an example:

  • 7:30am - first reading: 32,968.079
  • 06:30pm - last reading: 32,968.281

Consumption: 0.202 m³ in 11 hours.
Which works out at 1.9998 kWh in 11 hours, or 0.181 kWh/hour.

As there are 24 x 365 = 8,760 hours in a year, this represents 1,585.56 kWh a year.
Or 1,585.56 x 0.06 € = € 95.13 a year.

There you have it: the true cost of your pilot light. All that remains for you to do now is to consider if it is worth the expense of replacing it with an electronic ignition unit and to work out if this investment will pay for itself within a reasonable length of time courtesy of the savings an electronic unit will give you in terms of the reduced amount of gas used.

Then again, it is better to give this matter some thought before you decide on which kind of installation you want to have fitted. In light of the above, your gas-fired pilot light will have "burned" 951 € - a complete waste - or double the purchase price of an instantaneous water heater (excluding the cost to have it fitted), which should last you at least ten years. So in fact, you end up paying three times the cost of an instantaneous water heater. Getting an electronic ignition model from the outset, at a marginal extra cost, you will be investing your money the smart way.

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