Boiler Inefficient?

Hi,

We just moved into a new house with a Biasi 24S boiler and our gas bills have gone sky high. Worryingly when the heating is on, the gas meter is rolling round in front of my eyes. Having never watched one before I'm not sure if this is normal. I've calculated we used about 240kWh per day throughout the cold January/February. I'd be interested to know whether this sounds normal for a 2 bed semi? I'm concerned our boiler might not be working as efficiently as it should and we're wasting gas.

We were heating a living room, dining room, two mini bathrooms, kitchen and two bedrooms. Heating was on 6am to 9am, and 6pm to 12pm. Occasionally when very cold we would have it on a few more hours. I've turned a few of these rads off since receiving the bill, and I guess things will smooth out over the warmer months, but I still think the usage is much higher than I would expect.

Thanks for any advice,
JB.

JB, check in the garden for a large outbuilding. Look inside. Does it house a swimming pool?

Otherwise your calcs would indicate an average of 10kW heat input for 24 hours a day, or about 26kW for the 9 hours your heating is on, ie the boiler is running at full rate for 9 hours; this sounds improbable.

What is the gas usage over a 1 minute period when the boiler first fires at 6am and the rads are cold?
What is the usage over 1 minute once the rads get hot?
Does the burner regularly fire-up, then shut-down?
Do you have a water meter, is this constantly showing a flow above 10 litres per minute : i.e is there a hot water usage you don't know about?
Do you use large amounts of hot water?

Can you see the burner flame through a sight glass? Does it "lift" off the burner before going out, then re-igniting?


This info should enable us to home in on the likely fault.
I would hazard a guess that you are probably using twice as much gas as the typical for a two bedroomed house,

If you have a metric meter we need to know how much gas used over a 2 minute period

If imperial how long for 1 rotation of the dial?

I have a customer with a 3 floor terrace and a £2500 winter gas bill. Main problem is that they unwittingly keep the top floor roasting by not shutting doors, and the installation is all poor. Boiler outside and no pipe insulation, etc.

ChrisR said:

I have a customer with a 3 floor terrace and a £2500 winter gas bill. Main problem is that they unwittingly keep the top floor roasting by not shutting doors, and the installation is all poor. Boiler outside and no pipe insulation, etc.

Click to expand...

Turn the upstairs rads off and just use the heat coming up the stairs to heat the top floor

Hm just worked ours out 40 units a month over winter = approx 150Kwh a day. 5 bed detached house (1400sqft) 25 y.o. 50KBTU boiler. '80s built, '99 extension and fully double glazed.

Get some energy saving advice from HERE
Have a click about. You may be able to get grants for insulation and other energy saving devices.

My opinion is that its not worth changing for a condensing boiler unless you expect to save more than £300 a year.[ My estimated cost for installing and running a boiler over its expected 10 year lifespan] According to sedbuk.com your boiler is 78.3% efficient So for every pound you get 78.3p worth of usable heat. A band A boiler will give you 90p worth for the same pound.
If the 11.7 pences* saved dont add up to £300 [or your estimated figure] then dont go for a new one if the old one still works.

Blimey, what a great response. Thanks for all the advice. Also that sedbuk.com site is very informative.

Having cranked the thermostat down a long way, the house is fairly nippy but we used about 64kWh in one day (heating on 9 hours). A big improvement on the 237kWh average for the beginning of the year. It must have been turned up very high.

Best,
JB.