- Fitted protector: covers the top only. Bed bugs walk straight past the elastic skirt into the seams.
- Zip cover: better, but gaps at the zip end or an open underside let bugs in and out.
- Full-zip encasement: seals all 6 sides with a zip that closes with no gap. Bugs inside starve, bugs outside cannot get in. Keep it on for at least 12 months.
People use "mattress cover", "mattress protector" and "mattress encasement" as if they mean the same thing. For spills they nearly do. For bed bugs they are completely different products, and buying the wrong one is the most common reason we hear that "the cover didn't work".
Will the cover you already own stop bed bugs?
Answer 4 quick questions about your current cover.
Protector vs cover vs encasement: side by side
| Fitted protector | Zip cover | Full-zip encasement | |
|---|---|---|---|
| Main job | Spills and sweat | Keeping the mattress clean | Sealing the mattress completely |
| Sides covered | Top only | 3 to 5 | All 6 |
| Traps bugs already inside | No | No | Yes, they starve |
| Stops new bugs getting in | No | Not reliably | Yes |
| Easy to inspect | No, seams still exposed | Partly | Yes, smooth light surface |
| Recommended by pest controllers | No | No | Yes, after treatment |
Why the zip matters more than the fabric
A bed bug nymph is about the width of a full stop. If a zip stops 2cm short of the corner, or the zip pull leaves a small hole, that is a door. A proper bed bug encasement has a zip that runs the full way round and closes into a covered end stop, so there is no gap at all when it is shut.
The second reason is the underside. Bed bugs love the piping and the base of the mattress, the part that touches the bed frame. A cover that leaves the underside open protects the place they are least likely to be.
What to look for when you buy
- All 6 sides covered with a full-length zip.
- A zip end stop or flap so the closed zip leaves no gap.
- Fabric that bed bugs cannot bite through.
- The right depth: measure your mattress. A tight encasement can split at the seams, a loose one is fine.
- Comfortable to sleep on, because you will keep it on for at least a year.
For the full checklist, see our guide to the best mattress encasement for bed bugs.
Our bed bug range
Most popularBed Bug Mattress Encasement
Full zip, 6 sides, closes with no gap. Single to Super King Deep, plus cot.
Best valueBed Bug Protector Set
Mattress, pillow and duvet encasements together, so nothing on the bed is left exposed.
Frequently asked questions
Does a mattress protector stop bed bugs?
No. A fitted protector only covers the top of the mattress. Bed bugs live in the seams, piping and underside, which a protector leaves open.
Is a mattress encasement the same as a mattress cover?
Not for bed bugs. An encasement zips around all 6 sides and seals completely. Many "covers" zip around only part of the mattress or leave a gap at the end of the zip.
How long should I leave a bed bug encasement on?
At least 12 months without opening it. Adult bed bugs can survive many months without feeding, so the encasement needs to outlast them.
Can I put an encasement on a mattress that already has bed bugs?
Yes, that is one of its main jobs. Vacuum the mattress first, zip it in fully and leave it closed. Bugs trapped inside cannot feed and die.
Get the one that actually seals
Full zip, all 6 sides, no gap at the end stop. Free UK delivery.
Shop the bed bug encasement Protect the whole bedWritten by Richard Williams, founder of iDustMite, former NHS worker, guest speaker at the Allergy UK Show in 2025 and 2026, and adviser on over 1,000 one-to-one bedroom consultations. Reviewed October 2026.
