Gas vs Electric - Are my sums right ?

Mehullakhani

Hi All

We have just moved into a new home, it is a fairly large 5 bed house, over 3 floors, built about 7 years ago.

We have a gas boiler in the garage which provides hot water and heating for the house. We both work all day long, and get home about 6-7pm, and are out of the house by 7.30am in the morning.

We have the heating on for one hour in the morning, and about 4 hours in the evening weekdays, so 5 hours total.

The only room that we really use is the living room, the rest of the house has the rads turned down to a low setting.

To try and work out how much it is costing to heat the house, I had the heating on only, and then took two readings one hour apart, and this told me that I was using 1.48 m3 per hour .

When I look at my bill ( with BG, but changing to EDF ) , currently I pay 3p per kwh of gas.

My sum is :

1.48 x calorific value of 39.57 x volume correction of 1.022

then divide by 3.6 to get kwh

My sums show that it is using 16 kwh per hour to heat the house, and therefore about 50 pence per hour.

We can quite easily use a 2kw fan heater for one hour or at the most one and a half hours over the course of an evening to heat the living room quite nicely.

Therefore, are we better off using a fan heater in the evenings, and using the heating less, or are my calculations wrong ? Or is my boiler using excessive amounts of gas ?

Thanks

Mehul

KimYeovil

Your base sum is correct - 1.48 units on a metric meter are about 1.48 x 11.2 or 16.6 kWh. (Easier to just remember the x 11.2 approximation rather than go through the sum every time.)

What to do with the info depends - the extra kWhs from the central heating solutions are not magically evaporating. What is the result of the heating - are the pipes throughout the house warm and giving a small amount of heat through the house? Is that small amount enough to ward off damp? How low are the rooms with the radiators turned off - does it keep the air dry or is it undiscernible - is the extra heat from the boiler just heating the garage or is it actuallly giving a decent whack of ambient heat to the whole fabric of the house.

If your boiler is not just warming the garage walls then paying 'double' may well be worth the extra money.

One hybrid compromise may be to use an electrical towel rail/heater for the bathrooms and use them in the mornings and keep the central heating for evenings when you are at home.

HappyMJ

I've got to ask...Why buy a large 5 bedroom house for 2 people? Are you planning on a big family?

You will find a lot of cold spots throughout the house if you just use 1 fan heater. The kitchen will be freezing cold. The bathroom/toilet will be cold whenever you use them. Will the bedroom be warm enough? Also, it's usually the first hour of heating that costs the most as it's heating from cold. My boiler for a 3 bedroom house is rated 38kwh on max. The other 3 hours in the evening will be maintaining heat and may use about half what the first hour cost at around 18kwh. Which hour did you measure? Same with electric heating.