Boiler gas consumption

[yartin]

Hi

I have done a simple but accurate enough exercise about gas consumption of my boiler over a period of 80 days, the period chosen is due to billing and meter reading.
Boiler input gas consumption is:
Min 18.8KW
Mid 20.4KW
Max 22.0KW

I know exact number of hours boiler is ON daily, I know how many KWh consumed from the billing over the specified period. There is only one rough but near enough estimate of how may hours my 1.5KWh gas cooker is used and taken into account. I have room thermostat.
My calculation comes with the figure of 11.2KWh for the boiler gas consumption. I am not looking for an exact figure but Does this make sense?

Thanks

 

[Higgy28]

No, you are mixing up kW and kWh (a kW per hour doesn't make sense). Your boiler will, presumably, modulate somewhat too.
What are you hoping to achieve with these calculations?

 

[yartin]

No, you are mixing up kW and kWh (a kW per hour doesn't make sense). Your boiler will, presumably, modulate somewhat too.
What are you hoping to achieve with these calculations?

I changed it, I should have said 11.2 KWh.

 

[oldbutnotdead]

What are you trying to achieve?
Do remember that unless you have some advanced diagnostic kit you don't know how many hours your boiler is running. You do know how many hours that the boiler is enabled to run if room/water temperature drops below setpoint- that's a very different number, you can use it to develop a 'it costs x kWh per day to maintain setpoint y for hours z to zz.'
If you have a smart meter you can get more detailed information.

 

[fixitflav]

I changed it, I should have said 11.2 KWh.

Do you mean average 11.2 kWh (sic) per day? That seems on the high side unless you have a big house and the weather was cold.

 

[yartin]

I'm trying to work out boiler average consumption kWh and money cost per hour.

Boiler gas usage is 897 kWh when timer is ON for 80 hrs, costing £89.
897 kWh ÷ 80 hrs = 11.2 kWh (Average boiler consumption)

Calculate hourly cost when timer ON: £89 ÷ 80hrs = £1.11 /hr
Calculate hourly cost for a 11.2 kWh boiler: 11.2 kWh * 9.959p = £1.11 /hr
Both calculations give same figure.

 

[fixitflav]

I'm trying to work out boiler average consumption kWh and money cost per hour.

Boiler gas usage is 897 kWh when timer is ON for 80 hrs, costing £89.
897 kWh ÷ 80 hrs = 11.2 kWh (Average boiler consumption)

Calculate hourly cost when timer ON: £89 ÷ 80hrs = £1.11 /hr
Calculate hourly cost for a 11.2 kWh boiler: 11.2 kWh * 9.959p = £1.11 /hr
Both calculations give same figure.

Your calculations look OK. Clearly the boiler isn't firing all the 80 hours as 11.2 kW is less than boiler output. At that rate, over 30 days cost is nearly £800. A lot for most houses! But perhaps it's an hotel or a factory, you haven't said.

 

[yartin]

At that rate, over 30 days cost is nearly £800. A lot for most houses!

I think you are saying: 11.2kWh * 24 hrs/day * 30 days/month * 9.959p/1kWh gas = £800. IE: boiler on 24 hours a day 30 days a month, is that what you meant?

 

[fixitflav]

I think you are saying: 11.2kWh * 24 hrs/day * 30 days/month * 9.959p/1kWh gas = £800. IE: boiler on 24 hours a day 30 days a month, is that what you meant?

Yes, your 11.2kW is the average power (over 80 hours, which should give a representative figure). So you can multiply that by hours in a month.

 

[desktop987456]

Hi

I have done a simple but accurate enough exercise about gas consumption of my boiler over a period of 80 days, the period chosen is due to billing and meter reading.
Boiler input gas consumption is:
Min 18.8K

Which boiler is it, combi or system?