Gas vs Electricity - user test results wanted

HappyMJ

LittleMissAspie wrote: »

How do you work out the gas input figure?

Also does this presume that the appliance will be going full blast for an hour? Because in your example I'd have thought that the heater would need to be on for 5-6 times longer than the radiators to get the house or room to the same temperature. This would make gas less than 51p per hour but to get the actual cost you'd need to do some testing with a thermometer to work out how long each appliance needs to get up to the right temperature. And that depends on the weather too.

From the manual. It's the same with the oil filled radiator I use too. It's rated at 800W runs all night but switches on and off to maintain the room temperature and actually only uses 0.4kWh every hour....but if I used the gas boiler then the rest of the house would be warm too so that would be wasted heat when I only want the bedroom to be slightly warmer than freezing at night.

If I had an electric heater in each room then they only need to be on exactly the same time as the boiler to get the same heat out. Compared to heating a whole house with gas is just about always cheaper than heating a whole house with electric...this is just one room.

jalexa

HappyMJ wrote: »

12kW per hour for your boiler seems quite low.

I doubt the boiler could be flat out for 90 minutes, so the "12kW" is likely an average rating, limited by emitter size.

Note to OP, multiplying the elapsed 100cuft meter reading by 32 will give a good kWhr approximation.

prosaver

have you taken how much it cost to run a boiler without the gas on?

You will be shocked at these results
This is the cost of running a combi boiler without using any gas, just on stand by
1) Combi Boiler electric cost, stand by ...36 pence per day.. £131.40 per year
2) Insurance for boiler £10 a month 1 year £100 per year
3) Gas boiler life time is 10 to 15 years...plus fitting ./ £2000.. =£166 per year
Total cost................£397 per year with no gas running
hhehehehheheheh (peter griffin laugh)

Fred_Bear_2

To Prosaver: I have done this calculation myself and thought about eventually replacing my boiler with some immersion heaters on night rate electricity. The only problem is the cost of buying a large enough tank/cylinder to store the heated water. Re your calc: Where did you get the standby cost of 36p/day?
Here's my calc:
Gas standing charge (OVO) £63.00
Insurance & servicing (Homeserve) £224.52 (Not inc £50.00 excess)
Cost of boiler (London) say £2400 over 10 years £240.00
Total £527.52
That would pay for 11,700 units of night rate electricity..

lithopsian

Where do you get 36p/day in electricity for having the boiler do nothing? My old clunker with a pilot light didn't even cost that much. Are you assuming that the pump, fan, and everything else is running flat out 24/7? It isn't of course.

j2011

The way I work out the cost of a kWh of electricity whether you have 2 tier pricing or a standing charge is if 4750kWh of electricity in a year costs £627 then 1kWh of electricity costs £627 divided by 4750 which is approx 13.21 pence.

Same with gas.

tomsidebottom

Wow - there's a bit more to this than I first thought - as with most things I guess. Thanks for the confidence vote penrhyn - I guess I could work it out - unfortunately I should really get my head back into the old masters but I'll probably just save the rest of this task until I have a bit of spare time again and the motivation arises once again.

Jalexa - yes the boiler was moving between full rate and half rate - although the half rate seems to fluctuate a bit. It was basically just maintaining a water temperature of 75 degrees.

Prosaver those figures are definitely worth thinking about - especially when we paid for central heating to be fitted so we had to pay for all the pipes and radiators too - about £4500. It was a good job though and a good boiler - Vaillant Eco Tec 831 I think.

It'd be good if we could control each radiator using one control - turning off rooms we aren't using. I could go round turning them off and on of course...

Much food for thought anyway, many thanks.

Fred_Bear_2

tomsidebottom wrote: »

It'd be good if we could control each radiator using one control - turning off rooms we aren't using. I could go round turning them off and on of course...

Most of my rooms are controlled by a programmable room thermostat and a motorised valve. I can switch each room on or off from the kitchen. I am very happy with this but it is really only an option when the original system is designed. Also I think room stats control the rads more accurately than TRVs.

prosaver

lithopsian wrote: »

Where do you get 36p/day in electricity for having the boiler do nothing? My old clunker with a pilot light didn't even cost that much. Are you assuming that the pump, fan, and everything else is running flat out 24/7? It isn't of course.

I got it of the forum

Evidence
1) Electric cost
Post from Cornish saver
I've recently been given an 'electric smart meter' (connects to main electric supply to give real time electric usage in house).
I couldn't understand why we seemed to have a high constant electric use even when nothing much electric seemed to be switched on! I went round the house switching things on and off and checking the smart meter to eventually find that my Gas combi boiler which needs electric to run digital display is using 150 watts per hour. That’s without any heating on or hot water being drawn, no pumps or fans, JUST DIGITAL DISPLAY. I pay 10p per kWh, so am spending 36 pence per day.
3.6 kWh per day. That's a whopping £131.40 per year just to have my Gas combi boiler switched on, even if I don't use the heating or turn on the hot tap!!!
end of quote:p:p
however its not running just the digital display, there is a little pc inside the boiler waiting for someone to turn the tap on or the temperature to go down...
in the old day there use to be a timer that would manually click (like mine)

penrhyn

That is plain wrong.
Energy monitors measure out of phase products that are not recorded by your electric meter.
They are also incredibly inaccurate below around 250 watts.