The kitchen extractor fan used to be one of those things I didn’t think about.
You turn it on when cooking.
You turn it off afterwards.
That’s the whole story.
Except one evening in January I was standing near the hob waiting for the kettle and felt a very faint cold line across the back of my hand.
Not a breeze exactly. Just a thin thread of colder air moving past my fingers.
Which is never a good sign in a house you’re trying to tighten up.
At first I blamed the back door. That door has been responsible for several small crimes against heat already. But the door was shut tight and the draught strip was doing its job.
So I moved around the kitchen like someone checking for ghosts.
Near the fridge: nothing.
Near the door: nothing.
Under the cabinets: still air.
Then I stood under the extractor hood again and felt it.
A gentle downward leak of cold air through the fan grille.
Not dramatic. Just constant.
Which suddenly made sense.
Extractor fans are basically small holes through the house wall. When they’re running, they throw warm air outside. When they’re not running, they are meant to be sealed by a flap somewhere in the duct.
“Meant to be” being the important phrase.
I climbed onto the counter and popped the front cover off the fan.
The plastic flap inside was sitting half open.
Not broken. Just slightly warped with age so it never closed properly. That meant every time the wind pushed against the outside vent, cold air slid quietly back down the duct into the kitchen.
It wasn’t dramatic enough to notice day to day. But it was happening all the time.
Which is the exact kind of leak you want to eliminate.
I taped a thin strip of foam along the edge where the flap closed and put the cover back on.
Total time: about ten minutes.
The difference was immediate. The cold thread of air vanished. The kitchen just felt… neutral again.
Nothing dramatic. No fanfare.
But small fixes like this add up.
When we did Our first blower-door test: ugly numbers, simple wins
https://www.renewable-house.co.uk/our-first-blower-door-test-ugly-numbers-simple-wins/
the biggest lesson wasn’t that the house was terrible.
It was that the leaks were mostly boring.
Not giant holes. Just dozens of small ones quietly working together.
A warped fan flap here.
A loose loft hatch there.
A door seal that gave up years ago.
Each one barely noticeable on its own.
But together they keep the heating running longer than it needs to.
So the extractor fan has now joined the list of tiny things that no longer steal heat from the house.
Not a glamorous upgrade.
But the kitchen feels calmer.
And the kettle still boils just as quickly.
