If you have south- or west-facing rooms that feel like an oven each afternoon, you may be wondering whether blackout film actually keeps heat out—or if it just makes the glass darker. Here in Salt Lake City’s high-altitude sun, the answer matters. Below we break down how blackout film behaves in direct summer sun, what the numbers look like (TSER, IR rejection), when a true blackout is helpful, and when a modern spectrally-selective window tint performs better for comfort.

What “blackout Film” Really Does

Blackout film is an opaque privacy film—no visible light passes through. Because it blocks visible light (VLT ≈ 0%), it eliminates glare and gives complete daytime and nighttime privacy. However, heat control is not just about visible light. A significant portion of solar energy is infrared (IR) and some is ultraviolet (UV). If a blackout film has a low Total Solar Energy Rejected (TSER) value, the glass can still absorb and re‑radiate heat into the room. Quality architectural blackout films pair the opaque layer with a solar control stack to raise TSER into the 60–80% range; budget decorative blackout films may have far lower TSER.

Does Blackout Film Keep Heat Out?

It can—if you choose an architectural-grade blackout with high TSER and IR rejection, and if it’s installed on the correct surface of insulated glass. In practice, a premium solar-control blackout film reduces solar heat gain significantly, but so do modern spectrally selective tints that remain clear to moderately tinted. In Salt Lake City, we typically recommend high‑IR “heat control” films for living spaces where you still want daylight, reserving blackout for media rooms, bedrooms that need sleep darkness, or specialty privacy needs.

Summer Sun Performance Test (local Scenario)

To make this concrete, consider two side-by-side south-facing windows in Sugar House exposed from 1–5 PM in July:

  • Window A: Spectrally selective film (light, IR-focused) with TSER ≈ 55–60% and IR rejection ≥ 90%.
  • Window B: Architectural blackout film with TSER ≈ 70–80% (no visible light transmission).

Both reduce heat gain dramatically compared to bare glass. Window B will have the lowest peak BTU load because virtually all visible light is eliminated and TSER is very high. But Window A often provides the best comfort-to-daylight ratio for living areas because it keeps rooms bright while cutting the IR wavelengths that drive room heat. For most homeowners, this balance feels better day to day.

Where Blackout Film Shines

This section explains the key details and how they apply locally before we dig into specifics.

  • Media rooms and bedrooms that need true darkness at all hours.
  • Street- or neighbor-facing glass where 24/7 privacy is essential.
  • Spaces with projectors/monitors where glare must be eliminated.

In these cases, blackout film’s heat reduction is a valuable side benefit, and the zero‑glare environment is the primary goal.

Artscape window film Salt Lake City decorative pattern guide infographic
Artscape window film pattern options for rentals and resale in Salt Lake City — comparing DIY static cling to professional decorative film solutions.

Where Heat‑control Tint Wins

This section explains the key details and how they apply locally before we dig into specifics.

  • Kitchens, living rooms, and home offices that need daylight and views.
  • Sunrooms and large sliders where you want cooler glass without cave‑like darkness.
  • Older dual‑pane units where managing glass temperature differentials matters.

High‑IR, spectrally selective films can reject up to ~50–60% of total solar energy while maintaining a natural look. Many also block ≥ 99% of UV to help reduce fading.

Numbers to Watch (buyer’s Checklist)

This section explains the key details and how they apply locally before we dig into specifics.

  • TSER (Total Solar Energy Rejected): Aim higher for the hottest exposures (south/west).
  • IR Rejection: Prioritize films with strong performance in the near‑IR band (the part you feel as heat).
  • VLT (Visible Light Transmission): Pick the darkness that suits the room’s daylight goals.
  • Warranty + Glass Compatibility: Ask for a spec‑matched film and correct surface placement for your IGU type.

Salt Lake City Considerations

At altitude, UV and IR are more intense. For homes along the Wasatch Front, we usually start with a light or mid‑tint heat‑control film for living areas and use blackout selectively. If you’re exploring window tinting in Salt Lake City to beat summer heat, a quick onsite reading with an IR thermometer and a light meter helps us size the problem correctly and pick the right film family for each room.

Energy + Comfort Benefits

Both blackout films and modern solar-control tints can reduce cooling demand, trim peak load on HVAC, and improve comfort. Films that block UV also help protect furnishings from fading. For many homes, the sweet spot is a high‑IR, lighter‑shade film in social spaces plus targeted blackout in sleep/media rooms.

Good Next Steps

This section explains the key details and how they apply locally before we dig into specifics.

  1. Walk the house during a hot afternoon and note the rooms with the worst glare/heat.
  2. Decide where you truly need darkness versus where you want cooler glass with daylight.
  3. Schedule a consultation for film samples and a quick heat/visible-light reading on your glass.

Helpful Resources

For deeper background on how films manage solar heat and UV, see these neutral resources:

Explore Options + Get Pricing

If you’re considering blackout for a bedroom or media room—or a high‑IR heat‑control tint for living areas—our team can help you compare samples and numbers. Start with our Climate Control window film overview, browse home tinting benefits, or jump straight to a free consultation in Salt Lake City. We install high‑performance window tinting in Salt Lake City and across the Wasatch Front.