How to choose the right solar control film: a practical guide

Choosing the right solar control film should not be based only on its tint or appearance. First determine what task it must solve, then compare the technical specifications and check compatibility with the glass unit.

In this guide we look at how to choose the right window film for a home, office or commercial space.

1. Start with the main goal

The same film cannot suit all conditions equally well. For example, privacy requirements in a living room differ from protecting a large office glass wall from overheating.

Before choosing, answer a few questions: the room overheats in sunny weather; bright light and screen glare are bothersome; more daytime privacy is needed; you need to slow the fading of furniture, floors or shop-window goods; it's important to keep as much natural light as possible; you want to change the appearance of the glass facade.

A clearly defined goal helps rule out unsuitable options before comparing individual models.

2. Compare VLT, TSER and UV protection

Solar control film data sheets usually list several figures. Three of them are especially important to understand.

Visible light transmission – VLT

VLT shows what proportion of visible light passes through the glass with the film installed. A film with higher VLT preserves more natural light. A lower VLT usually means darker glass and may reduce glare more strongly.

However, VLT alone cannot accurately assess heat protection. Two films with similar light transmission may reflect and absorb solar energy differently.

Total solar energy rejected – TSER

TSER shows what proportion of all incoming solar energy the glass and film combination reflects and rejects. A higher TSER means stronger solar energy rejection under comparable measurement conditions. The actual result also depends on the glass unit type, window area and orientation, ventilation, shading and building features.

TSER should not be translated as a percentage of energy savings or a promise of a specific temperature reduction.

UV protection

This figure reflects the film's ability to reduce ultraviolet radiation transmission through the glass. Some Solar Screen films can reject up to 99% of UV radiation, but the exact value must be checked on the chosen model's data sheet. A high level of UV protection helps slow interior fading but does not stop it completely.

Read more about this in our article on UV protection film for windows.

3. Determine the suitable film type

The Solar Screen range includes reflective, neutral, tinted and almost transparent solar control films. Among the solutions used are the Silver, Vista, Chrome, Titane and Spectra series. When choosing, consider not only the level of heat protection but also the appearance of the glass.

Reflective films

Such films can provide strong solar energy rejection and a noticeable mirror effect. Daytime privacy depends on the difference in lighting outside and inside and should not be considered around the clock.

Neutral and low-reflective films

Suitable for sites where it's important to reduce overheating without creating a pronounced mirror facade. Their specifications vary, so specific models must be compared.

High light transmission films

Such solutions help preserve more natural light. The level of solar energy rejection may differ from model to model and should be assessed by TSER, not just external transparency.

Dark and tinted films

Can reduce brightness and glare more effectively but also affect room lighting and window appearance more strongly.

See available solutions on the solar control films for windows page.

4. Check film compatibility with the glass

Not every film suits every glass or glass unit. Before installation, consider: single glass or glass unit; number of panes and chambers; glass thickness and tint; presence of Low-E and other special coatings; tempered or laminated glass; window orientation relative to the sun; internal or external installation side; presence of previously installed film.

With incorrect selection, the glass may overheat, increasing the risk of thermal stress. Therefore compatibility must be checked against the manufacturer's recommendations for the specific glass and film combination.

5. Consider the room location

Windows facing different directions receive different amounts of direct solar radiation. South and west sides more often require stronger protection from overheating and evening sun. On the north side, preserving natural light may be a priority. For east windows, protection from bright morning sun is more important.

In large spaces, consider not only window orientation but also the total glazing area, room height, ventilation and external shading.

6. Don't mix summer and winter effectiveness

The main task of solar control film is to reduce solar energy input and room overheating in the warm season. Some films specifically designed for thermal insulation may also help reduce heat loss through the glass in winter. This is a separate specification that does not automatically apply to all solar control films.

If the winter effect is important, choose a model with confirmed thermal insulation figures and check its data sheet.

7. Assess the appearance before the final choice

Technically suitable films can differ noticeably in tint, reflection and transparency. A small sample does not always accurately show how the film will look on a large window or facade. Where possible, assess the sample on the site's window in daylight, viewing the glass from both inside and outside.

8. Check the installer's experience and warranty terms

A professional installer should determine the glass type, check film compatibility and choose the correct installation side. Quality installation helps avoid contamination, uneven edges, wrinkles and other defects.

Mirlex has been installing window films since 2016 and works in residential, public and commercial buildings across Estonia.

The warranty period depends on the specific film, installation location and manufacturer's terms. The wording "warranty up to 10 years" does not mean the same period for all products, so the terms must be confirmed before ordering.

Quick checklist