Combi Boiler Electricity Usage

Lil306

Hi All,

I'm busy looking at my items around my house with an electricity meter to see what is soaking up all the power.

Currently there are three things highlighting in red, but one of them that is my main concern is the boiler.

I have a Baxi Combi 105 HE Boiler.

I read the boiler manual and it states power consumption ~180w, is this the power used 24x7 to keep the thing "online", so to speak. Or is this the power drawn only when it's in use.

My electricity tarriff works out at 16.9 per kw/h

At 24x7 usage (180w consumption) - this works out at £21.90 per month on electric, is this correct or am I reading the boiler power calcs wrong

The only other things drawing huge amounts of electric are my computer which I'll be migrating offsite and lightbulbs which I'll be changing to HE / LED.

Currently my tarriff is £76 DD

Consumerist

Lil306 wrote: »

. . . I read the boiler manual and it states power consumption ~180w, is this the power used 24x7 to keep the thing "online", so to speak. Or is this the power drawn only when it's in use.

This 180W is likely to be the maximum consumption of the boiler's electronics, pump and any back-lighting bulbs included.

If you're using a watt-meter, you need to measure consumption (kWh) over a minimum of 24 hours and this will obviously vary depending on the season.

Edit
If your boiler and pump was running 24/7 (most unlikely) then your calculations look about right.

Lil306

Consumerist wrote: »

This 180W is likely to be the maximum consumption of the boiler's electronics, pump and any back-lighting bulbs included.

If you're using a watt-meter, you need to measure consumption (kWh) over a minimum of 24 hours and this will obviously vary depending on the season.

Edit
If your boiler and pump was running 24/7 (most unlikely) then your calculations look about right.

Thanks,

I may email the company to confirm the power requirements and what exactly it's drawing this from. One of my friends mentioned on facebook it's most likely the standby power. Except I don't know if standby power is always on or only when in use .

I have no way to confirm power draw as my boiler is hardwired into my electrics in the household, it's not on a plug as such

I've measured all the other electrics in my household, nothing has changed in the 3 years of me living here except the direct debits have gone from £48 p/m to £76, so I'm looking at reducing everything and starting afresh

Scrounger

Lil306 wrote: »

... the direct debits have gone from £48 p/m to £76..

Probably mostly due to rising energy costs.

You should run a quote through a comparison site as 16.9p/kWh seems expensive.

Scrounger

Andy_WSM

Lil306 wrote: »

One of my friends mentioned on facebook it's most likely the standby power. Except I don't know if standby power is always on or only when in use .

They are wrong. The rating plate on an appliance is the maximum amout of power that appliance will draw in a worst case scenario. So on a boiler that would be whilst it's burning gas (the gas solenoid uses power), the combustion chamber fan will be running & the pump will be running - as well as the control electronics and any indicator lamps.

In a standby situation the power draw will likely be a minimal 5-10W. Maybe even less than that.

I have in the past seen people state that they repeatedly turn the boiler off at the wall to save them 2p a day in standby power, then the same people are complaining 6 months later that the boiler has gone wrong and a pcb has blown costing hundreds of £s to repair.

Leave the boiler to do what boilers do. It will end in tears otherwise.

As stated by Scrounger, most of that rise can be put down to year on year 20% increases in charges, but your tariff sounds about 1 or 2p per kW too much - depending on whether you also pay a standing charge or not.

Cardew

Agree with the above, the 180W will be the maximum consumption with pump and fan running etc.

macman

You cannot rely on the portable energy monitors-they give very inaccurate readings, especially at low levels.
Use your own electricity meter with everything else switched off.

Smiley_Dan

Isn't the pump spec'd depending on the length of pipework and number of rads? Our pump uses more like 400w when running.

Cardew

Smiley_Dan wrote: »

Isn't the pump spec'd depending on the length of pipework and number of rads? Our pump uses more like 400w when running.

That seems high.

Central Heating Pumps

Most systems use a pump to circulate the hot water which runs all the time the heating is operational. In a normal size installation this will use between 50W and 200W. The amount of power used is dependent on the pump speed which is likely to be variable, at least on modern pumps.. From experience quite a few are installed with the speed set to maximum (and hence maximum power consumption). Reducing the speed significantly, especially in a small property) may have very little effect apart from saving electricity. There is a down side to doing this - the heating does tend to take longer to reach temperature.

http://product-selection.grundfos.com/catalogue.html#/Product%20catalogue/Applications/Heating/ALPHA/ALPHA2

This Grundfos pump is 32W or 45W.

I have quite a large house(approx. 40 radiators*) and my variable speed pump is 15W to 45W.(not a combi pump)

* panels

Lil306

Scrounger wrote: »

Probably mostly due to rising energy costs.

You should run a quote through a comparison site as 16.9p/kWh seems expensive.

Scrounger

Thanks, I'll check it out. I suspected rising energy costs as I've lived in the same house for 3 years now and literally nothing has changed in terms of setup

Andy_WSM wrote: »

They are wrong. The rating plate on an appliance is the maximum amout of power that appliance will draw in a worst case scenario. So on a boiler that would be whilst it's burning gas (the gas solenoid uses power), the combustion chamber fan will be running & the pump will be running - as well as the control electronics and any indicator lamps.

In a standby situation the power draw will likely be a minimal 5-10W. Maybe even less than that.

I have in the past seen people state that they repeatedly turn the boiler off at the wall to save them 2p a day in standby power, then the same people are complaining 6 months later that the boiler has gone wrong and a pcb has blown costing hundreds of £s to repair.

Leave the boiler to do what boilers do. It will end in tears otherwise.

As stated by Scrounger, most of that rise can be put down to year on year 20% increases in charges, but your tariff sounds about 1 or 2p per kW too much - depending on whether you also pay a standing charge or not.

Thank you, I'm on a standard tariff with npower
Tarriff Name: Standard SC DD
Tariff Type : Variable
Method : Monthly DD
Unit Rate : 16.85kWh

Estimated Usage (based on current) - 4,401 kWh
Projection : £741.68

Npower online summary already states I'm on their cheapest tariff for what I use.

Only reason I haven't left yet is because I wanted to let their early exit fees be avoided by staying with them a while (and a bit of ignorance because I was lazy) :o

Cardew wrote: »

Agree with the above, the 180W will be the maximum consumption with pump and fan running etc.

Thank you, I don't know how much electricity boilers consume, so wanted to double check if that 180w was pulled all the time or if it was only used in a certain amount

macman wrote: »

You cannot rely on the portable energy monitors-they give very inaccurate readings, especially at low levels.
Use your own electricity meter with everything else switched off.

I can do, I wasn't using a portable power meter, my information was taken purely from the manufacturers website that's why I needed to double check the consumption

Lil306

The cheapest tariff details

http://oi62.tinypic.com/maje6c.jpg

8.98kWh, anyone have experience using them?