Today I have some good news.

The energy usage in our house has fallen spectacularly. In December, I had to pump 7.3kW of heat into the house 24 hours a day to maintain a steady 16C using my hideous gas boiler. Now I am pumping in 2.3 kW and maintaining 19C.

You would expect me to attribute this all to my mega efficient heat pump but this is not the case. Approximately half the saving was made here but the other half is due to insulation and draft proofing.

The most effective savings were stopping draughts round the front door and insulating the floor voids and bare floor boards on the ground floor. Cavity wall and loft insulation made no perceptible savings im afraid, lagging the roof and walls in a draughty house has no impact,

Vented floors are a disaster when it comes to energy saving. In my house 50% of the heat loss is caused by some idiot building the house 18 inches off the ground and then letting the air whip through the void using air bricks.

I decided the only solution was to fill the voids with lagging by pumping it in from outside using the airbricks as access. I discussed this at length with lagging companies and they said it was impossible. The main concern is that if the floor voids were filled there would be no ventilation so the floors would rot. Rubbish I said!

This is standard practice in America, there they fill the voids with polystyrene balls (fire proofed) and reduce the losses, who cares if it gets wet at the bottom polystyrene is waterproof.

In the end I went to B&Q, bought some loft lagging, ripped up the floors and filled the floor void round the outside wall with 2 foot of lagging, there is still some air movement but it is greatly reduced.

So the message is to save energy in old houses don't mess about, scrap the old boiler and put in a new efficient alternative and draft proof the place.

Just as a guide to stop the drafts cost me £20 of lagging (B&Q have an offer on) and a day to fit it. I will save that amount from my energy bill in under a week. Now that's payback.