might be a silly question - but can somebody try to help?

[Ludi]

Hi,
the question is - how much of m3 of gas should boiler burn in 1 hour when it's on? looks like we used over 4oo m3 of gas in 4-5 weeks (approx 45oo kwh - if that's correct) . We checked the meter this morning and it looks like it's about 2 m3/per hour. we have a combination boiler, potterton?, 2bed bungalow, 8 double panel radiators in the house. our heating is on for a few hours in the morning, max temp. 18-19C and few hours in the evening, at night it's down to 15C - so it's usually off.
Does 2 m3 per hour sounds right? the bill will be then over £300 for 1month which i think is a lot... used to pay that much for 3months in my previous flats/house. Many thanks.
Regards Ludi

 

[Bahco]

Read this. You should be able to work out your usage.

 

[kevindgas]

we would need to know the exact model to be able to tell you a maximum usage
£300 does sound very high though. get it checked by an RGI and make sure you get a Tightness Test carried out as well you may have a small leak somewhere in the system.

 

[Ludi]

it's potertton puma 80e
thank you

 

[D_Hailsham]

looks like we used over 4oo m3 of gas in 4-5 weeks (approx 45oo kwh - if that's correct).

Assuming the heating is on for three hours in the morning and four in the evening and assuming 400m³ over 4 weeks , the average hourly consumption is 400 ÷ (4 x 7 x (3+4)) =2.04m³ per hour.

The Potterton Puma 80e is a 24kW boiler. At full output it will be using just over 2m3 per hour. This means that your boiler is running at full output all the time. But it should only be running at full output when heating the hot water or when it is very cold outside.

How well insulated is your house?

if you are only running the heating for a couple of hours in the morning and a few in the evening, the house is continually heating up and cooling down. What temperature do you have set during the day, when the heating is off? Is it 15C as at night? If it is, try turning both down to 10C.

What type of programmer and thermostat do you have.

When was the boiler last serviced?

 

[Ludi]

Many thanks for your responses.
House is insulated but now that i think there is no heating in the kitchen with a back door to the garden, and loads of cold air gets through that door. The thermostat is honeywell. temp during the day when the heating is not on is usually on 15C, will try to turn it down. But looks like it's running ok, isn't it? 2m3 per hour. so if we have it on for app 7hours a day, it's 14-15 m3 per day. i'm shocked it's so much. forgot to mention that the boiler is in the garage, not in the house, not sure if that's important. are there any more efficient boilers currently on the market? or you think this is 'normal' for the boiler and usage. it was serviced last year, next service is due in may. anything else you can suggest? Once again, thanks for your time. And knowledge.
Ludi

 

[Agile]

Measure the gas consumption for ONE hour during the heating time but AFTER the house it up to temperature.

The house should not be consuming 24 kW !

You are obviously using a lot of gas but its not clear why yet.

You have not described the house yet!

Tony

 

[Ludi]

Hi,
by 'Measure the gas consumption for ONE hour during the heating time but AFTER the house it up to temperature' - are you saying that i should heat up the house to lets say 18C and when the thermostat will turn off, i should turn it back on for 1 hour and measure how much it uses? sorry, i'm not very familiar with these things...
the house is a 2 doublebed detached bungalow, made from bricks, each bedroom has one 2 panel radiator, all windows in the house are double glazed, it has 1 bathroom with 1 small radiator, 1 hallway with 2 small radiators and entrance door, 1 living/dining room with 2 radiators. there is a small kitchen with no heating and a back door to the garden (which looks like will need to be replaced) . garage (used as a storage,utility room) is attached to the house and has 1 radiator.

 

[D_Hailsham]

House is insulated but now that i think there is no heating in the kitchen with a back door to the garden, and loads of cold air gets through that door.

What insulation do you have?
Cavity wall?
Loft? How much?
Double glazed windows? Metal or UPVC?

A 24kW boiler is relatively large for central heating, unless you have a very big house. Use the Sedbuk Boiler Calculator to find out how much heating you should have (deduct 2kW from the final answer as you have a combi boiler).

2m3 per hour. so if we have it on for app 7hours a day, it's 14-15 m3 per day. i'm shocked it's so much.[/quote]
I shouldn't be averaging 2m³ per hour; Only at initial start up. The boiler should be automatically reducing it's output as the house gets hotter

forgot to mention that the boiler is in the garage, not in the house, not sure if that's important.

The boiler has built-in frost protection, which turns the boiler on if the temperature drops below 5C and turns it off when it reaches 10C. Do you have any other frost protection?

Looking at the list of rads you should check that the are giving enough heat. If you use the Stelrad Elite Catalogue you should get a good idea.

Do you really need a rad in the garage?

 

[Tipper]

How much hot water do you use?

A combi boiler runs at full output much if not all of the time the hot tap is running because that's what it is designed to do.

 

[Ludi]

The walls are solid, loft has some insulation but don't know how much, so let's assume the minimum. house is not that big, about 120-130 m2. i've tried that Sedbuk Boiler Calculator, i got 17.8, hopefully i've done it correctly. does it sound right? windows are double glazed upvc. when the heating is on, radiators do get very very hot, but the house does get cold very quickly when they are off. there are no carpets in the house, just wooden flooring. also the water in a hot tap is extremely hot when it's on, both in the kitchen and bathroom. we use hot water, all together for about 40min -50 min a day. we don't have to have a rad on in the garage, it's on coz we use it as a utility room and leave clothes to dry in there. but we could possibly turn it off.

 

[Ludi]

..and boiler hasn't got any other frost protection

 

[ianniann]

Which month is this for? If it was February (extremely cold) then 400m3 is hardly excessive. If it was March (fairly warm in England at least) then it does seem a bit high even for a poorly insulated house.

 

[Ludi]

last 2 weeks of Feb and last 2 weeks of March. heating was off first 2 weeks of march as we were away.

 

[D_Hailsham]

The walls are solid, loft has some insulation but don't know how much, so let's assume the minimum. house is not that big, about 120-130 m2. i've tried that Sedbuk Boiler Calculator, i got 17.8, hopefully i've done it correctly. does it sound right? windows are double glazed upvc. when the heating is on, radiators do get very very hot, but the house does get cold very quickly when they are off.

Sounds about right for solid walls.

The only problems with Sedbuk is that it is not always very clear, .i.e that:

All dimensions are internal
Room height is floor to ceiling
A mid-terrace has two external walls
A semi/end terrace has three external walls
A detached has four external walls

also the water in a hot tap is extremely hot when it's on, both in the kitchen and bathroom.

What do you have the hot water temperature control (top right knob) set to on the boiler?

There's not much you can do about solid walls, but I would get the loft insulated as soon as possible.There are plenty of low cost or free schemes around at the moment. See Energy Savings Trust Grant Search.

What time and temperature controls do you have? Do the radiators have TRVs?