Living as I do in a 1920s house with solid brick walls (no cavity, no insulation) the recent cold snap made it really clear just what a difference insulation makes. The modern flat I was in previously was bordered on most sides by other flats, and its exterior walls were no doubt well insulated. The heating didn't have to work very hard, but in the new house it had a struggle on its hands and ran nearly continuously through the freezing weather, whilst only very slowly raising the internal temperature. You could almost feel the heat (and the money, and my eco credentials) draining away through those cold solid walls.

I've been on a mission to improve the odds in my favour since I moved in, having done the following.

• Improve sealing around the front door, which was quite draughty, by adding self-adhesive strips of V-profile sealant tape. Did the same for a draughty window.
• Improve sealing around the back UPVC doors by adding shims to the closing mechanism and adjusting the locking system to get it to close more tightly and cut out the draught.
• Put some clear tape (literally just ordinary Sellotape) on the frame of a UPVC window that was allowing a tiny draught. This wasn't the gap between window and frame but an imperceptible gap in the frame itself!
• Installed secondary double glazing on the few single glazed windows in the house. This is a clear film that you stick up on the inside with double sided tape then shrink smooth with a hairdryer. The air gap that you trap acts just the same as normal double glazing and is not immediately noticeable.
• Improved loft insulation by adding 150mm space blankets in most of the eaves. These are great – easy to handle because they're wrapped in thin plastic and crazy cheap at most hardware stores because they're heavily subsidised. I had to be careful not to lay them over wires though (they might overheat) which is tricky as most of the rooms below have a light in the middle of them and hence wires going to those lights from the loft. I'd love to know how everyone else solves this wiry problem, given pretty much everyone must have it.
• Added 50mm slab insulation (glass fibre insulation bought in flat semi-rigid slabs, rather than in rolls) to the backs of the plasterboard walls in the converted loft. This stuff is great as you just cut it with a knife to slightly larger than the size required and jam it into the spaces, where it stays. I got a single pack from Wickes, which covers over 7 square metres and only cost me £15 because the pack was damaged and they gave me a discount. I reckon that's £15 well spent and I hope it will make the loft noticeably warmer. The pictures show this stuff being cut (above) and installed (below) with the left-most bit of wall still to do, showing just the shiny back of the plasterboard – so you can see before and after in one shot.