A £6 experiment in loft insulation and heating bills

£6 of loft insulation from B&Q

The house I live in gets a bit cold in Winter, and no matter how long I run the heating for the upstairs rooms just don’t seem to warm up that much compared to downstairs.

Of course in Summer upstairs is like an oven, and the loft is equally extreme in its temperatures – being either inhospitably cold in winter or unbearably hot in summer.

B&Q (with the aid of some sort of government “save the carbon” type grant) sells rolls of loft insulation for the insane price of £3 (or £2.98 for the value stuff which doesn’t look as thick) so I thought I’d buy as much as will fit in the boot of my car and see if it makes any noticeable difference to the temperature of the house.

Existing insulation that doesn't go all the way to the eves

Before adding the new insulation I had to reposition and repack the existing pink fibreglass-based material. It looks to have been installed quickly by a previous occupant as it didn’t go all the way to the walls. It looks like they didn’t buy enough since after poking it around with a pole (to avoid getting fibres stuck in my skin) it fell between the joists and had even larger gaps.

Existing insulation that doesn't cover all the floor/ceiling

One useful and possibly intentional design was that each roll of insulation was long enough to run the length of the house, and three rolls side-by-side was enough to cover the ceiling between the outer wall and where the loft boards started. My loft has been boarded out for storage so if the place still feels cold I might see if I can cheaply buy insulated boards to put down too.

Before I added this insulation the house usually drops down to around 12-14C overnight when the heating is off, providing a wonderfully cold and damp atmosphere for growing mould behind cupboards. I’ll see what it’s like tomorrow morning with the new insulation in place.