Boiler KWH Usage

FesLerdinand

Hello everyone. Simple and probably stupid question, but please humour me.

I have an Alpha CD25C boiler. According to the manufacturer, it should use 25 KWH. However, my gas meter is clocking it at 29 KWH just running the central heating. I've isolated it from all other gas appliances to reach that number - no hot water, no gas cooker used for one hour, just the heating.

My question: Is it normal for a boiler to run at 16% over its specified usage?

The reason I ask is because I've only lived in this house for a year and my gas readings have been coming out eye-wateringly high ever since I had my new meter installed, which happened to coincidence with the onset of Central Heating Season. I need to decipher if the meter is reliable, and if so what I can do to reduce that KWH usage down.

The boiler looks old and probably hasn't been serviced for a couple of years. I keep some of the upstairs radiators turned off but the house is quite large and hard to warm up. I've ruled out any gas leaks or pre-existing meter readings on my new meter as the cause of the high usage. I'm just getting murdered on my gas usage and I can only make the numbers add up if my boiler is consistently over-using energy.

Thanks in advance for any patient assistance offered.

Gerry1

According to the spec, the Heat Input (Gross) is 26.7kWh and the Gas Rate is 25.5 m³/h

However, the latter equates to 28.4kW (using a gas calorificvalue of 39.2), so your reading seems pretty good !

matelodave

Dont forget that the boiler wont be roaring away at full blast once the house has been heated and the thermostats have taken control. It's also got a modulating burner which will reduce the burning rate. Don't have the flow rate too hot and make sure the boiler runs in condensing mode to maximise efficiency

However, combis do flog away at full bore when you turn the hot tap on so learn to use hot water wisely by not running off short bursts to rinse your hands or stuff, use cold water for that.

Not only do you waste water whilst it gets up to temperature, but the boiler will run on for a few minutes after you've turn the tap off. You'll also end up with a pipefull of lovely heated water to get stone cold until the next time you turn the hot tap on.

Talldave

You have picked the wrong month to get stressed about gas consumption! We're currently burning through almost 1500kWh a week, but in summer consumption would be less than a tenth of that.