Energy Consumption

[Edward W. Thompson]

I am trying to get some idea on how energy 'efficient' we are in our home. To give some background, we have recently relocated from a two bedroom mid terrace cottage in the south of England to a four bedroom detached house in the East Midlands. At our previous home cooking was by a gas range with an electric oven in our newhome coking is all electric. Occupany two 70+year olds.

For a similar period ( Feb to April) at the cottage we were using about 11kw/hr per day electricity and 25kW/hr per day for gas central heatring and water. At our new home electricity iks about 12kW/hr per day but central heating and water is 70kW/hr per day, a very significant difference.

As far a insulation is concerned, the cottage had the front and back (Outside walls) insulated Loft insulation was about 100mm glass fibre. The house in East Midlands has had the walls insulkated about one month ago and the roof space has been converted to two bedrooms about

12 years ago, before we bought the property. The eves are insulated with glass fibre, again about 100mm at a guess.

I appreciate having the walls insulated will, or at least should reduce the heating demand, lets assume by 10kW/hr per day so would

60kW/hr per day for central heating and water in winter conditions for a four bedroom house seem 'reasonable' or excessive?

[CJF]

You could download Builddesk UK from

- you will need to register, but it is free. It's intended to do U value calculations for simple and complex building materials, in composites where necessary. Armed with this information on your house materials, you could then use the Barlo heatloss calculator from is intended for radiator sizing, but it gives heat losses for each room, and from this you can get an idea of where your heat is going, and perhaps more usefully what measures are most cost effective for reducing losses.

Both the programmes take a bit of learning, but the results are interesting once you are up and running.

Charles C

[Ed Sirett]

There are so many possible variables. Method of construction, size, age of house and obviously not all CH systems are equal (see boiler choice FAQ).

BTW 70 units/day is not way out of line for a four-bed detached house.