Professional Guide

Best Window Insulation Film for Draughty Homes: 2025 Expert Review

DR Joinery

Expert Joiner & Restoration Specialist

Published 16 December 2025

If you live in a Victorian terrace or a listed property, you'll know the specific chill that radiates from single-glazed sash windows. Whilst nothing beats professional draught-proofing and timber restoration, secondary glazing film is an effective, non-invasive interim solution to stop heat escaping.

I often advise clients that until we can schedule a full refurbishment of their sash boxes and staff beads, applying a thermal shrink film can significantly improve comfort. Ideally, this creates a sealed air pocket that acts similarly to double glazing units.

In this review, I've categorised three insulation films that serve different needs: a budget option for quick fixes, a heavy-duty film for high-traffic areas like patio doors, and a bulk roll for homeowners tackling multiple windows.

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Specs vs. The Real World

The Spec: "Double Glazing Effect"

The Theory

"Marketing claims suggest these films provide the same insulation value as modern double glazing units."

The Reality

They create a static air gap which reduces convection heat loss, but they lack the vacuum or argon gas of real units. They stop draughts brilliantly, but don't expect 2025 building regulation U-values.

The Spec: "Damage-Free Removal"

The Theory

"The double-sided tape peels off cleanly in spring without damaging the window frame."

The Reality

On modern uPVC, yes. On older painted timber (common in York), the tape can lift loose paint or varnish upon removal. I always recommend heating the tape gently with a hairdryer before peeling it off.

My Top 3 Recommendations

Three options to cover different needs and budgets

RYSONS Window Insulation Kit Fit Double Glazing Shrink Film Draught Excluder Condensation

Budget Pick

RYSONS

This is your standard, no-frills option. It does exactly what it says on the tin for the price of a coffee. It's thinner than premium brands, but if you just need to seal a couple of bedroom windows for the winter months, it's a cost-effective choice.

Price£3.19 (at time of writing)

CoverageInsulates approx. 2 standard windows (1m x 1.5m)

Film Size1.57m x 1.82m

The Good

Extremely affordable entry point
Sufficient transparency for bedroom usage
Includes everything needed for a quick install

The Bad

Film is thinner and tears easier during installation than premium brands
Tape adhesion can be hit-or-miss on uneven painted timber

Installer Tip:

Clean the sash and frame thoroughly with methylated spirits before applying the tape. Any dust or grease on old joinery will cause the tape to fail within days.

Priced at £3.19 at the time of writing

Check Price on Amazon

Duck MAX Strength Window Insulation Kit, Fits Patio Doors & Large Windows

Quality Pick

Duck

In the trade, we appreciate durability. This film is significantly thicker and puncture-resistant, making it the only sensible choice for patio doors or large sash windows in high-traffic areas where children or pets might brush against the film.

Price£25.90 (at time of writing)

DurabilityMax Strength (Puncture Resistant)

Pack Size2 Pack (84" x 120" sheets)

The Good

Much thicker gauge film withstands accidental knocks
Crystal clear finish looks more professional once shrunk
Excellent for large draughty French doors or garden rooms

The Bad

Considerably more expensive per square metre
Requires more heat to shrink effectively due to thickness

Installer Tip:

Because this film is thicker, don't overheat one spot or you'll distort the view. Keep the hairdryer moving constantly. Also, ensure your beading is sound; the tension on this stronger film can actually pull at loose beading.

Priced at £25.90 at the time of writing

Check Price on Amazon

FLYZZZ Window Insulation Kit for Secondary Glazing Effect , 1.6x10m Window Insulation Film

Problem-solving Pick

FLYZZZ

This is the problem-solver for those tackling a whole floor or large bay windows. The 10-metre roll allows you to cut custom sizes (perfect for non-standard Victorian joinery), and the extra-wide tape provides a better bonding surface on older, uneven frames.

Price£15.99 (at time of writing)

Film Length10 metres (Huge Roll)

Tape Width2cm (Extra Wide)

The Good

10-metre roll is ideal for bespoke window sizes found in older properties
Wider 2cm tape offers far better adhesion on painted timber frames
23-micron thickness balances durability with ease of shrinking

The Bad

Requires careful measuring and cutting (not pre-sized sheets)
Managing a large roll can be tricky alone - grab a helper

Installer Tip:

The 2cm wide tape is this product's best feature. When applying to sash windows, try to stick the tape to the 'staff bead' (the inner trim) rather than the sash face itself. This creates a larger air gap and reduces condensation risk.

Priced at £15.99 at the time of writing

Check Price on Amazon

Frequently Asked Questions

Does window film stop condensation on single glazing?

It helps significantly. By creating a barrier between the warm room air and the cold glass, you stop the moisture from condensing on the pane. However, if moisture gets trapped inside the film during installation, you might see fogging. I recommend installing on a dry, crisp day with the heating on.

Can I open my sash windows once insulation film is applied?

No, once the film is taped and shrunk, the window is sealed shut for the season. If you need ventilation, consider filming only the top sash or leaving one window in the room untreated. For a permanent solution that allows operation, you'd need professional draught-proofing strips routed into the timber.

Will the adhesive tape damage my painted wood frames?

There is always a risk with adhesive on painted timber, especially in older York properties where paint layers might be decades old. To minimise damage, remove the tape slowly in spring using a hairdryer to soften the glue. If paint does lift, it's a good opportunity to sand and re-prime, which protects the wood long-term anyway.

Is window film a substitute for sash window restoration?

Not permanently. Film is a temporary 'bandage' for winter. It stops draughts but doesn't address the root causes like rotting sills, broken sash cords, or rattling frames. Restoration involves repairing the joinery and installing integrated draught seals for a lifetime solution.

How do I get the creases out of the film?

The hairdryer is key. Once taped up, the film will look saggy. Start heating from the corners and work inwards. Don't touch the film with the dryer nozzle. As the plastic heats, it shrinks tight effectively like a drum skin, becoming clear and taut.

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