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Fabric window seal vs acrylic panel

Updated: 20 October 2026

A zip kit and a cut acrylic sheet both claim to close the hole around a portable air-conditioner hose. A fabric window seal is the removable cloth in our [air conditioner window seal comparison](/hub/cooling/air-conditioner-window-seal). An acrylic or foam-board panel is cut to the opening, and it is not one of those twelve rows. Peter F. used the amazon.co.uk listings from 19 October 2026 and Aircon Revolution's guide of 9 September 2026. It is not a lab comparison. A qualifying purchase of a listed cloth kit can earn a commission at no extra cost to you. Choose fabric if you will not cut. Choose a rigid panel for a long hot spell if you can measure.

A zip kit and a cut acrylic sheet both claim to close the hole around a portable air-conditioner hose.

Our top picks

DREO DREO 400 cm window seal

Best overall

DREO DREO 400 cm window seal
7.3/10about £19.99
View offer
Machine-YA Machine-YA 300 cm window seal

Best value

Machine-YA Machine-YA 300 cm window seal
7.2/10about £16.38
View offer
BTSAE BTSAE cuttable casement sheet

Rank 3

BTSAE BTSAE cuttable casement sheet
3.1/10about £7.99
View offer
On this page
  1. 1.Why the gap matters on a single-hose unit
  2. 2.What a zip kit is good at
  3. 3.What a cut panel demands
  4. 4.Which to use

Why the gap matters on a single-hose unit

A single-hose unit blows warm air outside and pulls replacement air back through the same window. Aircon Revolution treats a rigid panel as the tighter way to shrink that hole, and it does not publish a bill saving. A zip cloth or a cut-out panel makes the opening smaller. It does not make it zero. MOEGFY's bullets say a minimal gap may remain at the zipper, and Machine-YA and EGNBU reviews describe air still moving there. Ideal Home's fitters suggest a short, straight hose run of about 50–60 cm. That figure is their advice, not a measurement from this set.

What a zip kit is good at

A zip kit needs no saw and, on these listings, no drill. You tape the frame, zip the hose, and unhook the cloth when the window must shut. That suits a rental, a short hot spell, and a hinge a flat panel will not sit in. Machine-YA reviewers describe fits of about 10 minutes. Electrovision says the window is not secure while the cloth is up. The Machine-YA zip does not lock, and LYUNIT reviews describe glue perishing around 30°C. The BTSAE sheet at about £7.99 is 2.0 from 18 reviews because the tape sticks to the frame and not the sheet. One reviewer switched to Perspex. A zip gap is not a mesh. Length and slider exclusions are on the buying guide.
DREO DREO 400 cm window seal

Testsieger

DREO DREO 400 cm window seal
7.3/10about £19.99
View offer

What a cut panel demands

A rigid panel is cut to the opening, edged with foam tape, with a hole for the hose. Plasticsheetsshop describes that for outward casements, and the shop sells the sheet. You need the width and height in millimetres. Ideal Home passes on a warning from Cut My: do not use ordinary glass, and do not alter a rented window permanently. Acrylic or polycarbonate is the material those sellers mean. A foam board seals better than a baggy cloth only if the cut is square, and it is easy to push in from outside. A panel 5 mm too wide will not enter the frame. Measure with the sash in the position you will use. Hinged geometry is on the casement page. portableairconditioner.uk quotes custom inserts at about £80–£150, against fabric at about £15–£20. Those ranges are theirs, not prices in this set.

Which to use

Use the fabric kit if you must take it down, if the hinge is awkward, or if a short spell fits a measured 300 cm or 400 cm perimeter. The top pick for a stated casement is the DREO 400 cm cloth, and the best value under 300 cm is the Machine-YA. Use a rigid panel when the same casement will run through a long hot spell and you will cut acrylic or polycarbonate, not glass. Neither option locks the window. Take the seal down when you leave if that is what lets you lock the sash. Fitting the cloth is the how to fit page.

Common questions

Which seals a single-hose unit better?
A rigid panel that actually fits the opening leaves a smaller edge gap than a zip cloth. Aircon Revolution argues that, and the cloth listings themselves allow a gap at the zipper. The panel only wins if the cut is right. A badly sized board leaks through the slot you missed. No figure in this set is a measured cooling gain.
Can you rent with either option?
You can rent with a fabric kit if the tape comes off the frame and you do not drill. Derwit reviewers include that reason. You should not alter a rented window permanently, which is the warning Ideal Home passes on. A panel leaned in the opening, and taken away when you leave, is removable. A panel screwed to the frame is not.
Does fabric keep insects out as well as a panel?
The cloth listings claim an insect barrier, and some reviewers notice fewer flies. A zip that does not close on the hose is still a gap. A close-cut panel blocks that path more consistently. The BTSAE sheet includes a mesh, and its reviews are about the sheet falling off, not about a proven screen.
Is acrylic worth it for one hot week?
Usually not, next to a cloth kit around £16–£20 in this set. A custom hard insert in the £80–£150 band quoted by portableairconditioner.uk is a lot of money for a few days, and that band is theirs, not an amazon.co.uk price here. Acrylic earns its place when the same window will be in use for a long spell and the zip leak bothers you every evening.
What must you not cut the panel from?
Do not cut it from ordinary glass. The breakage and the edge are the hazard, and a rented window should not be permanently altered. Use acrylic, polycarbonate, or a foam board you can remove. Follow the seller's cutting notes. A wrong size is harder to live with than spare cloth you can roll up.
Do you still need a short, straight hose?
Yes. Ideal Home's fitters suggest about 50–60 cm, short and straight, between the unit and the window. A long hose dumped in a coil keeps heat in the room even if the window seal is tidy. The seal covers the opening. It does not shorten the duct.

Related pages

Best window seal

Air conditioner window seal

Choosing a portable air conditioner window seal kit

Casement window seal for a portable air conditioner

How to fit an air conditioner window seal properly

Sources

Public UK sources from the research digest, used for this page on 20 October 2026. Prices, stars, and review counts are the amazon.co.uk figures in the 19 October 2026 snapshot. NHS and GOV.UK pages do not recommend these kits.

  1. NHS: heatwave, how to cope in hot weather (retrieved 19 October 2026)
  2. GOV.UK: beat the heat, keep cool at home (retrieved 19 October 2026)
  3. Consumer Rights Act 2015, section 9 (retrieved 19 October 2026)
  4. GOV.UK: product safety advice for businesses (retrieved 19 October 2026)
  5. GOV.UK: reporting product safety issues (retrieved 19 October 2026)
  6. Aircon Revolution: window seal kits for portable air conditioners (retrieved 19 October 2026)
  7. Ideal Home: portable air conditioner window kits (retrieved 19 October 2026)
  8. Appliances Direct: how to install home air conditioning (retrieved 19 October 2026)