Thermal Insulation Window Film: Low-E and Energy Saving Film in the North West
Thermal insulation window film, often called low-e or energy saving window film, is a thin, almost clear film that reflects heat back into the room instead of letting it escape through the glass. It is the winter-side partner to solar control film, which deals with summer heat.
It is also easy to oversell, so we will be straight with you. The improvement is modest, it suits some glass far better than other glass, and it will not replace double glazing. This page sets out where it is worth doing and where it is not. We supply and fit thermal insulation window film across the North West: Greater Manchester, Cheshire, Merseyside, Lancashire and Cumbria, including Manchester, Salford, Liverpool, Chester, Preston, Lancaster and Carlisle.
The short answer
Low-e film reduces the heat that radiates out through the glass. It makes a noticeable difference on single glazing and some older windows, a small difference on older double glazing and almost none on modern low-e double glazing. It is a useful extra, not a substitute for better glazing.
How heat leaves through a window
Heat leaves a room through glass in three ways: conducted through the pane, carried away by moving air and radiated as long-wave infrared, the type of heat given off by radiators and people. Glass is poor at stopping the last of these, and it makes up a large part of the loss through single glazing.
A low-emissivity, or low-e, coating is a microscopically thin metallic layer that reflects that long-wave heat back into the room. Modern double glazing often has one built in. Thermal insulation film adds the same kind of layer to glass that does not have it.
What it can do, and what it cannot
What it can do
- Reflect some heat back into the room
- Make single glazing and older units feel less cold to sit beside
- Take a modest edge off heating demand, depending on the glass
- Often add UV protection and some glare control at the same time
What it cannot do
- Match replacement glazing or secondary glazing
- Stop draughts through gaps in frames
- Make a measurable difference on modern low-e double glazing
- Deliver the large savings that some adverts suggest
Which glass, and what to expect
| Glass | Typical result | Our view |
|---|---|---|
| Single glazing | The most noticeable improvement | Worth considering, though secondary glazing does more |
| Older double glazing | A modest improvement | Worth a conversation. Check the glazing warranty first |
| Modern low-e double glazing | Little to none | Not worth it. The coating already does the job |
| Conservatory with a glass roof | Modest in winter, while summer heat is the bigger problem | Choose a film that handles both. See solar control film |
| Single-glazed shopfronts and offices | Noticeable | Worth considering, especially with UV protection |
Low-e, thermal and energy saving: the same family
- Low-e film
- Short for low-emissivity. The technical name for a film with a heat-reflecting layer.
- Thermal insulation film
- The retail name for low-e film fitted to existing windows.
- Energy saving window film
- A broader marketing term. It can mean low-e film, solar control film or both, so ask which.
- U-value
- How easily heat passes through a window. Lower means better insulated. Film can lower it a little. Replacement windows lower it a lot.
Winter and summer: the trade-off
A film that keeps summer heat out also keeps some of the winter sun out, and one that keeps winter heat in can trap summer heat. Which matters more depends on the room.
In a conservatory the summer problem is usually bigger. The room is too hot to use for months, and too cold for a few weeks. We would normally tackle summer first with a solar film, and look at winter second. Some films do both, with a modest effect on each, and we can talk you through them.
Cheaper or better things to try first
If cold is the main problem, there are other things worth doing alongside, or before, film.
- Draught-proofing: often the cheapest and most effective step.
- Thermal curtains or blinds: good for evenings.
- Secondary glazing: an inner pane that insulates far more than film on single glazing.
- Replacement glazing: where windows are failing or very old.
We would rather tell you that than fit film you do not need. Where film does make sense, we are happy to quote.
Related jobs
We have not yet published a job that was specifically thermal insulation film. These are jobs on conservatories and glass rooms, where winter heat loss and summer heat gain both matter, filmed for solar control.
Conservatory Window Tinting for a Bungalow in Euxton near Chorley
Taking the heat and brightness out of a sunroom with sunlight coming through the sides.
Conservatory Roof Tinting in Sale
Solar window film fitted to the glass roof of a conservatory in Sale. See the interior photos and how conservatory roof tinting is done.
Window Tinting for a Glass Garden Room in Hale Barns
Reflective window film fitted to the sliding glass walls and roof of a glass garden room in Hale Barns. See the photos and how the roof was filmed.
Glass Patio Canopy Tinting in Cheadle Hulme
Reflective solar control film on the glass roof panels of the patio canopy.Thermal film across the North West
We fit thermal and solar films across the North West, from older houses in Lancashire and Cumbria to period conversions in Cheshire. Where a home needs a proper insulation fix, we will say so.
The North West is cooler and wetter than much of England, so winter heat loss through old windows matters here. Thermal insulation film is most asked for on older glass in the Pennine towns of Greater Manchester and Lancashire, in the period houses of Chester, and in the stone houses of Cumbria around Carlisle and the Lakes. In Merseyside it suits older terraces and seafront houses in Liverpool and Southport, and in Lancashire the Victorian streets of Preston and Lancaster.
It is not a replacement for good glazing, and we say so, but on single glazing or tired double glazing it can take the edge off a cold window across Greater Manchester, Cheshire, Merseyside, Lancashire and Cumbria. The honest advice is the same in Manchester as in Carlisle: we survey free and recommend it only where it helps, in Salford, Liverpool, Chester, Preston, Lancaster or elsewhere. See the areas we cover across the North West.
Thermal insulation film questions
Is low-e film the same as thermal insulation film?
Yes. They are different names for a film with a low-emissivity layer that reflects heat back into the room.
How much will it save?
It depends on the glass. On single glazing the effect is noticeable. On modern double glazing it is small. We do not promise a figure, and be wary of anyone who does.
Will it stop condensation?
Not reliably. Condensation depends on humidity, ventilation and temperatures, and film is not a cure.
Can it go on double glazing?
Sometimes. Some combinations can affect the glass or the glazing warranty, so we check first.
Is it better than secondary glazing?
No. Secondary glazing insulates far more. Film is cheaper and less visible, and suits glass where secondary glazing is not an option.
Will it reduce my summer heat as well?
Some thermal films have a little solar control, but for real summer heat reduction you want a solar film. See solar control window film.
Do you fit thermal insulation film across the North West?
Yes. We fit thermal insulation window film in Greater Manchester, Cheshire, Merseyside, Lancashire and Cumbria, including on older glass around Manchester, Salford, Liverpool, Chester, Preston, Lancaster and Carlisle. The benefit is modest, it is not a substitute for better glazing, and we say honestly whether it is worth it for your windows.
Cold glass in winter?
Tell us what the windows are and how old they are. We will say honestly whether film is worth doing or something else would serve you better.
