Anyone checked central heating cost per hour?

Grogsy78

I ran my central heating for 30 mins this morning to check the energy cost via my smart meter.  My smart meter went up by 0.37p, though just checked again and its showing 0.94p used.  Anyone else checked their usage per hour?  Will have to try take manual readings tomorrow.

[Deleted User]

Several people have, but it's not a useful number because it depends on so many other things than just "amount of time turned on".

You could run your heating for 100 different hours and you would probably get 100 different costs.

[Deleted User]

Hi,

it costs more at start up until house heats up, here's a similar THREAD yesterday.

[Deleted User]

Grogsy78 said:

I ran my central heating for 30 mins this morning to check the energy cost via my smart meter.  My smart meter went up by 0.37p, though just checked again and its showing 0.94p used.  Anyone else checked their usage per hour?  Will have to try take manual readings tomorrow.

Download the App BRIGHT and you can get usage and cost data. As suggested above, a 24kW boiler will start off with an output close to 24kW which will decrease (modulate) as the heating demand decreases.

Grogsy78

Found this on google so at the current rate is 10.2 pence per kWh approx thats £2.44 per hour so guess the smart meter is working fine

A 24 kW boiler will use 24 kWh of energy per hour. According to Choose, the cost is approximately 3.8 pence per kWh, which means it would cost around 91 pence to run a 24 kW boiler for one hour. This will change depending on the cost of gas and the size and age of your boiler.  

[Deleted User]

Except a 24kW boiler would only use 24kWh per hour if it was running at 100% output continuously throughout the whole time.  Which they don't (as Dolor's graph shows).

[Deleted User]

Grogsy78 said:

Found this on google so at the current rate is 10.2 pence per kWh approx thats £2.44 per hour so guess the smart meter is working fine

A 24 kW boiler will use 24 kWh of energy per hour. According to Choose, the cost is approximately 3.8 pence per kWh, which means it would cost around 91 pence to run a 24 kW boiler for one hour. This will change depending on the cost of gas and the size and age of your boiler.  

Too simplistic. All boilers have a modulation ratio which reduces the boiler output as the heating demand decreases. A typical 24kW boiler will modulate down to 7kW. Once the heating demand drops below 7kW, then the boiler will cycle on/off.

Most domestic boilers are massively over-sized because big boilers offer rapid HW heating. My previous 5 bed home could have managed with a 18kW boiler.

For a modern condensing boiler, another key factor is the temperature of the return flow to the boiler. The lower the return temperature; the higher the boiler efficiency and the lower the boiler running cost.

Ballymoney

Our 30kw boiler is currently using about 35kwh of gas to heat our 4 bed detached to 18c from 8am - 10pm (plus 2 showers). About 15kwh of that total is used in the first 45mins and the remaining 20kwh for the next 13 hours.

With the current mild temps once your initial 30mins is over your boiler will use very little to maintain the house temp.

Grogsy78

[Deleted User] said:

Grogsy78 said:

Found this on google so at the current rate is 10.2 pence per kWh approx thats £2.44 per hour so guess the smart meter is working fine

A 24 kW boiler will use 24 kWh of energy per hour. According to Choose, the cost is approximately 3.8 pence per kWh, which means it would cost around 91 pence to run a 24 kW boiler for one hour. This will change depending on the cost of gas and the size and age of your boiler.  

Too simplistic. All boilers have a modulation ratio which reduces the boiler output as the heating demand decreases. A typical 24kW boiler will modulate down to 7kW. Once the heating demand drops below 7kW, then the boiler will cycle on/off.

Most domestic boilers are massively over-sized because big boilers offer rapid HW heating. My previous 5 bed home could have managed with a 18kW boiler.

For a modern condensing boiler, another key factor is the temperature of the return flow to the boiler. The lower the return temperature; the higher the boiler efficiency and the lower the boiler running cost.

So basically the cost will drop once the water in radiators is heated and it takes less energy to keep them hot, so question on whether its better to keep them on for longer than use them randomly from cold every time. 

[Deleted User]

Yes, the boiler usage per hour will fall once the set temperature has been reached. Heating demand will vary throughout the day as the outside air temperature varies plus there are such things as solar gain to take into account. 

My experience - based on running my system boiler at 60c; with a set temperature of 19C on the 2 main thermostats and individual TRVs set at no lower than 13C - is that it is better to to run the heating constantly. My annual usage over the last 12 months was less than 7000kWh (it was though a mild Winter). We live in a 4 bedroom house with two retired occupants at home all day.

That said, others will have different opinions based on their lifestyles.

PennyForThem_2

Grogsy78 said:

I ran my central heating for 30 mins this morning to check the energy cost via my smart meter.  My smart meter went up by 0.37p, though just checked again and its showing 0.94p used.  Anyone else checked their usage per hour?  Will have to try take manual readings tomorrow.

This device you are getting the cost from is NOT your Smart Meter - it is your In House Device (IHD).  Ahhhhhhhhhhh!