Window Film Percentages Explained: VLT, TSER, IR and UV

Four numbers do most of the work, and they measure four different things. VLT is the share of visible light that gets through. TSER is the share of the sun's total energy the filmed window rejects. IR rejection covers the infrared band only. UV rejection covers ultraviolet.

A fifth number, solar heat gain coefficient, describes the same property as TSER on a scale of 0 to 1, where lower means less solar heat. The National Fenestration Rating Council tests, certifies and labels window films for energy efficiency, and an NFRC label carries SHGC, visible transmittance and U-factor.

Sorted by what each one decides for you:

• TSER and SHGC decide how hot the room gets
• VLT decides how bright the room looks and how dark the glass reads from the street
• UV rejection decides how fast floors, art and furniture fade
• IR rejection describes one band of the spectrum, not the whole of it

TSER decides comfort, because it counts the entire solar spectrum while IR rejection counts one part of it. Lawrence Berkeley National Laboratory notes that roughly half the energy in sunlight is infrared, so a film can post a large infrared number and still pass a lot of total energy into the room.

Madico's Sunscape sheet shows the gap inside one product line. Measured on 6mm clear single pane glass, Advanced Ceramic 5000, 4000 and 3000 publish IR rejection of 66%, 75% and 83% against TSER of 44%, 50% and 58%, with VLT of 53%, 46% and 35% and 99% UV rejection.

The same split runs through Madico's architectural films on that same 6mm basis. Nova 70 publishes 78% IR rejection against 46% TSER, Solar Grey 20 publishes 83% against 64%, and Reflective Silver 20 publishes 94% against 76%. Across both sheets, every film's IR figure is the larger of the two.

None of that makes an IR number dishonest. It makes it the wrong number to rank films by. If a quote leads with IR rejection and never prints TSER, ask for TSER before you compare it against anything else. Our guide to the best window film for heat is built on the same rule.

Three different pieces of glass, which is why two honest numbers for the same film can disagree. NFRC's film directory rates applied film on 3mm clear monolithic glass. Madico's own sheets use 6mm clear single pane. Tekton publishes single pane and double pane columns side by side.

Nova 70 sits on two of those bases. NFRC lists it moving SHGC from 0.71 bare to 0.46 filmed on 3mm clear glass, while Madico's own sheet reports SHGC 0.54 on 6mm clear. Both are correct. Neither travels to your windows without the basis attached to it.

Double glazing moves the figure again, and not always in the same direction. Tekton publishes Keramos 35 at 57% TSER single pane and 47% double pane, and Keramos 55 at 42% and 38%, while Fortis 4 mil runs the other way at 15% single pane and 24% double pane.

That is the tell that these are ratings for a filmed window rather than for a film on its own. If your windows are double pane, a single pane rating is a starting point and not a promise, so ask which column the number came from.

It tells you what a film does to heat and light on a stated basis, and it leaves out TSER. NFRC publishes SHGC, visible transmittance and U-factor for applied film as paired bare and filmed values, and its film directory is public and searchable. It does not publish TSER or UV rejection, so every TSER figure in this industry, including the ones on this page, is supplied by a manufacturer.

From Madico's NFRC listing, on 3mm clear glass:

Read the last row against the third. CL 800 PS SR moves SHGC by 0.03 and visible transmittance by 0.03, so it changes heat and light barely at all. Night Scape 7% takes light from 0.74 down to 0.07 while SHGC only falls to 0.23, which is a privacy result rather than a heat result.

If a spec table shows a TSER figure and an NFRC reference together, those are two different kinds of claim. One is measured by the maker, one is certified independently. Both can be true, and knowing which is which is the whole point of reading the sheet.

VLT answers that, and the product name does not. On 6mm clear single pane glass, Madico publishes Nova 70 at 68% VLT, Frost Matte at 67%, Solar Grey 55, 35 and 20 at 57%, 35% and 19%, Reflective Silver 40, 30 and 20 at 44%, 30% and 19%, and Blister Free 200 at 89%.

Darker usually rejects more, but construction changes the trade. Madico's Solar Grey grades run TSER of 37%, 53% and 64% at those light levels, while Reflective Silver runs 56%, 68% and 76%. At 19% VLT the two lines let through the same amount of light and reject 64% against 76%.

Tekton's Keramos grades sit in the middle of that spread, at 35%, 46% and 54% VLT on single pane and 32%, 42% and 49% on double pane, with SHGC from 0.43 up to 0.62 depending on grade and glazing.

One caution on vocabulary. Tekton publishes SIRR, or solar infrared rejection, at 84%, 76% and 69% for Keramos 35, 45 and 55. That is not the same measurement as the IR rejection figure on a Madico sheet, so the two should not be lined up against each other. If you arrived here from percentages quoted for vehicle glass, that is a different product class with its own rules, and it is not work we take on.

Most films sold for heat, glare and privacy do, and Madico's own sheet prints the exception. On the 2023 architectural sheet, Nova 70, Solar Grey, Reflective Silver and Frost Matte all publish 99% UV rejection, while Blister Free 200 publishes 39% UV rejection alongside 89% VLT and 16% TSER. Tekton publishes greater than 99% UV rejection for Keramos and Fortis.

So 99% UV is a property of most films sold for solar and privacy work, not a property of window film as a material. If fading is your reason for buying, get the UV figure for the exact film and grade on your quote, on a stated glass basis, rather than accepting the category claim.

Ask for the four numbers and the glass they were measured on, in writing. A percentage with no basis is not a specification, and the manufacturers say so themselves. Madico prints the caveat on both sheets: "Reported values are typical properties and should not be used as a specification." - Madico, Architectural Film Performance Measurements, revision 3/23.

The short list to hand any installer:

• The exact film name and grade, not only the brand
• VLT, TSER, UV rejection and SHGC for that grade
• The glass those figures were measured on, 3mm or 6mm, single pane or double pane
• Whether the TSER figure is the manufacturer's or from an independent label
• What that film costs across your actual window count

We quote by film and by window rather than by category. You can sanity check a budget with the window film cost estimator, see how we weigh products against each other in window film brands compared, read what we install for heat on the heat and solar control film page, or ask Joey for a free measured quote. We publish the manufacturer's figures with the basis attached, and we do not publish a rejection number we cannot point at a source for.