Our house is the best ever for gas consumption... shocking!

My partner put all the gas consumption figures for our previous three houses and this one into a spreadsheet and our 1930s detached performed better overall* even with the old inefficient boiler and single-glazed windows (we have secondary glazing only on the north side and 1 double-glazed window - nearly all windows are single-glazed iron-framed originals). We had a boiler replacement yesterday so it's going to get even better!

We think this is due to loft insulation and cavity wall insulation. The secondary glazing might play a part too but it's quite old and makeshift for certain windows.

So what were the other houses? We moved a lot in the past five years so the houses we compared were:

• A Victorian semi with original single-glazed sash windows and combi boiler
• A 1930s semi with double-glazed windows and brand-new combi boiler
• A 1960s semi with double-glazed windows and combi boiler.

Strange but true! Cavity wall insulation beats double-glazing big time!

*Bearing in mind that we had the coldest and longest winter ever!