At a glance: a sky lantern in Amersham, Buckinghamshire, fitted with 3M All Seasons 35 inside the glass.

Roof lantern in Amersham fitted with 3M All Seasons 35 film — The lantern after filming

The challenge

A roof lantern floods the room below with daylight. In summer it floods it with heat too, straight down onto the people underneath, with glare to match. The aim was to take the heat and glare out without losing the light that is the whole point of a lantern.

What we fitted, and why

3M All Seasons 35, fitted inside the lantern glass. It is a spectrally selective reflective film: it turns back far more of the sun’s invisible near-infrared heat than its visible light, so the room stays bright while the heat drops. Fitting inside also works on glass with a self-cleaning coating, which exterior film will not stick to.

What 3M All Seasons 35 does

On 3M’s double-glazing reference, 3M All Seasons 35:

Cuts solar heat gain by about 54%
Cuts glare by about 65%
Blocks 99% of UV, one of the main causes of fading
Cuts winter heat loss through the glass by about 11%

Second view of the Amersham roof lantern with 3M All Seasons 35 — Daylight kept, heat and glare cut

Every figure we quote is the improvement you can expect over the glass you have now. To see what that means on a hot day, look at the June roof chart on our conservatory roof film page.

What the owners said

“We are very happy with the product and the installation. The service that we received from everyone was excellent and we would definitely recommend WindowTreat to a friend.”
Nicola and Ian, Amersham

Your next step

See our roof lantern and skylight film options, inside and out. We quote from your photos.

Why 3M All Seasons 35 succeeds where other internal films fail.

Does conservatory window film work? Our verdicts on the films we fit and the ones we avoid.

Talk it through with a specialist

Book a free, no-obligation callback at a time that suits you. We will talk through your room or project and the options that fit, including honest guidance on what will not work.

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Prefer to talk now? Call 01256 648000 or message us on WhatsApp.

Author: Steve Gargett, Managing Director

Steve Gargett has been helping people transform their spaces with window film since 2008. With a physics degree and full completion of the Chartered Institute of Management Accountants examinations, he brings a rare blend of technical understanding and financial rigour. Earlier in his career, Steve held senior financial and project roles within a Fortune 100 company, where he learned the importance of value for money and strong returns on investment. Today, he uses specialist modelling software from the Lawrence Berkeley National Laboratory in California to predict how glazing will perform before and after film installation. Every recommendation is based on independently tested films, giving customers confidence in fact‑based, tailored advice. He has supported homeowners, architects, and commercial clients across the UK, always focusing on what matters most to each customer and delivering solutions that balance performance, appearance, and long‑term value.