How to Choose a Letterbox Draught Excluder
Measure your letterbox first
Standard UK letterboxes are usually around 250-300mm wide, but older doors can vary. Measure the width and height of your letterbox opening before ordering, since an excluder that's too small will leave gaps and one that's too large won't fit the frame properly.
Brush vs flap vs box style
Brush-style excluders are the least intrusive and easiest to fit but offer moderate draught blocking. Flap and combined designs block more air but add bulk to the inside of your door. Fully enclosed box designs offer the best draught and noise blocking along with a post-security benefit, at the cost of being the most visible fitting.
Don't forget the outer flap
Many letterboxes already have an external metal or plastic flap that's become loose or warped over time — if yours rattles or doesn't sit flush, replacing or tightening it alongside fitting an internal brush will improve results significantly.
Installation is almost always simple
The vast majority of letterbox excluders fit with two or three screws directly onto the inside of the door, over the existing opening. No specialist tools or skills are needed for any of the options compared here.