Electricty used by gas heating

MikePh

Hi everybody

We live in a rented 3 bedroom detached house

The central heating is gas fired with radiators using a reasonably new (around ten years I believe) boiler

I noticed from my bills that we have been using considerably more electricity in the winter than in the summer.

Having made careful daily records, it would appear that when the central heating is on to keep the house at around 18 degrees, our daily electricity usage goes from an average of around 6 kW per day to an average of around 10 kW per day

The heating is never switched on for more than 12 hours a day

Should a gas central heating system use that much electricity? The extra electricity use equates to around an additional £25 each month

I should add that the landlord is not over keen on spending money on maintenance and the system gets only it’s gas safety check once a year. It has not been serviced for at least 7 years

Thanks in advance

jrawle

It sounds quite a lot. The main electricity usage will be the pump, which could be up to 100W. The boiler itself and any valves may also use a few watts. (What sort of system? Combi/gravity fed?) You say it's on for 12 hours a day, but presumably the actual running time is less as the thermostat will switch it off for much of that period. Even if it was on for 12 hours solid, that's 0.1 x 12 x 30 = 36 kWh, so around £7 or £8 per month.

Do you have a lot of lights on in the winter? And do you use low energy lights?

MikePh

Thanks for that rapid reply  jrawle

Worcester Greenstar Ri  Condensing boiler

Yes, the thermostat is indeed turning the system on and off.

The readings are a direct comparison beteen heating on and heating off, nothing else has changed (and every light is low energy anyway)

My maths told me that because of switching on and off, the monthly spend should be more like £2 per month additional.

Could the pump be faulty? could that cause the high use?

(typo edit)

Robin9

It's about 15.30 and in my house lights and TV on ; getting ready for a cooked tea    Compare with the summer - no lights, out in garden; salad for tea.

MikePh

Thanks Robin

We tested one day heating on, next day heating off. Everything else as was

victor2

MikePh said:

Hi everybody

We live in a rented 3 bedroom detached house

The central heating is gas fired with radiators using a reasonably new (around ten years I believe) boiler

I noticed from my bills that we have been using considerably more electricity in the winter than in the summer.

Having made careful daily records, it would appear that when the central heating is on to keep the house at around 18 degrees, our daily electricity usage goes from an average of around 6 kW per day to an average of around 10 kW per day

The heating is never switched on for more than 12 hours a day

Should a gas central heating system use that much electricity? The extra electricity use equates to around an additional £25 each month

I should add that the landlord is not over keen on spending money on maintenance and the system gets only it’s gas safety check once a year. It has not been serviced for at least 7 years

Thanks in advance

Only the pump will use any significant amount of electricity, and that should be nowhere near the extra 4kWh per day you say you are using (note it is kiloWatthour, not just kiloWatt).

You could be confusing yourself and jumping to the wrong conclusion. Simple test is to look at your electricity meter at two times say an hour apart and take readings. Do this with both the central heating on and off, but everything else running as normal. Your fridge cutting in will cause a small spike in usage, so do it a few times and/or listen for your fridge running during the timed periods.

Depending upon your type of meter, you can often get an idea of usage at any time by looking at the dial (on a mechanical meter) or flashing LED (on a digital one), and working out how that relates to kWh used.

The_Fat_Controller

I have a combi boiler and my heating on from 0600 to 2030, the pump and fan use around 100 W as the previous poster estimated, that's from the IHD readings which seem to be pretty accurate, even down to a 6 W LED bulb being turned on and off.

It runs for less than half of that period, so that is a maximum of 0.8 kWh/day 

What kind of system do you have and is the pump running continuously when the heating is on ?

jrawle

It seems unlikely a worn pump would cause a 10x increase.

Where do the usage figures come from? Are you taking manual meter readings? Are you sure there is nothing else you use in the winter? How is your water heated? Do you use an electric fire in the living room or an electric blanket? Do you use a tumble dryer instead of drying outdoors?

I guess this is where a smart meter would come in useful. You could see how much the usage increased when you start the heating. (In theory, you could actually work this out from the speed of the spinning disc in an old-style meter.)

zagfles

Other thing may be that your fridge and freezer would be working harder with higher temperature, since the temperature difference between inside and outside is obviously less if the house is cooler.

MikePh

Thanks for the reply @victor2

First of all I don't want to get into a discussion but kiloWatt/hour is a measure of how much energy you're using per hour (kilowatts per hour). The total amount of electricity I have taken from the grid in a day is measured and charged in kilowatts. (e.g at 4 pm I was consuming 4 kwh but only until 4.30. Therefore I had consumed 2 kw)

Very carefull measurements have been taken hourly, 4 times a ady, twice a day, daily, weekly,and monthly
They all show that when the heating is on we are using significantly more electricity


@jrawle
Nothing else being used, no electric heaters, no electric blankets etc etc
I will give you an example
day 1     Electric oven used for 1 hour, washing machine 40degree cycle, various low power lights on and off, hot water on for 20 minutes, NO HEATING ON……………     5.2 kW

day 2     Microwave for 4  minutes, hot water for 20 minutes, various low power lights on and off, HEATING ON   ……..  10.7 kW

smart meter  being installed next week !!!!


@zagfles  Thanks for reply.   Are you saying that freezer and fridge drawer significantly more in a colder room?

victor2

MikePh said:

Thanks for the reply @victor2

First of all I don't want to get into a discussion but kiloWatt/hour is a measure of how much energy you're using per hour (kilowatts per hour). The total amount of electricity I have taken from the grid in a day is measured and charged in kilowatts. (e.g at 4 pm I was consuming 4 kwh but only until 4.30. Therefore I had consumed 2 kw)

...

smart meter  being installed next week !!!!

OK.

Your new smart meter will have an In-House Display, which will show you how much electricity you are using at any point in time (typically updated every 10 seconds I believe). The amount of gas it shows you as using at any one time is pretty meaningless, as they only update once every 30 minutes IME, so it depends if your boiler was actually firing or not at the moment it took the reading.