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Place · Field Notes № 01 · 7 min read

How to keep a house cool in a Las Vegas summer.

Mass, mesh, and the four hours of evening you can earn back. A working argument against the louvered pergola.

Editorial March 12, 2026 Henderson, NV · 36°02′N

Las Vegas summers push 115°F. The AC is working overtime, the bill climbs, and somehow the house still feels warm at five in the afternoon. The problem usually starts at the windows. They account for forty to fifty percent of the cooling load in a typical valley home — and the worst of them are the west-facing ones, which take direct sun during the hottest hours of the day.

Start with the windows

If you do one thing, address the west-facing windows first. They take direct afternoon sun during the hottest part of the day, and that heat pours through. South-facing windows are the next priority. Everything else can wait.

  • West-facing windows are the biggest problem and the biggest opportunity.
  • Solar screens on west-facing windows make the largest single change to indoor temperature in any house we have measured.
  • South-facing windows are second priority; they catch sun for longer but at a lower angle.
The cheapest fix is geometry. Most houses are pointed wrong before anyone hangs a screen.

Thermostat strategy

  • 76°F during the day, 74°F at night.
  • Every degree below 78° increases cooling cost by 3–5%.
  • Use a programmable thermostat. Raise the setpoint when no one is home.

Ceiling fans, used correctly

  • Run them counterclockwise in summer to push air down.
  • Fans let you raise the thermostat 2–4° without noticing the difference. That swing pays for the fan in one summer.

Seal the gaps

  • $20 of caulk around windows and doors saves $30–50 per month.
  • Check the weatherstripping on every exterior door. If you can see daylight through the seal, replace it.

Shade the condenser

  • A shaded condenser runs roughly 10% more efficiently than one in direct sun.
  • Keep two or three feet of clearance for airflow. A shaded box that can't breathe is worse than a sunny one that can.

What is not worth the money

A few common upgrades sound right and don't actually move the number much in a Mojave summer:

  • Attic fans. Minimal impact when it's 115° outside. The attic is downstream of the windows.
  • Reflective roof coatings. Marginal benefit on most single-story homes; not worth the cost unless you are reroofing anyway.
  • Blackout curtains alone. By the time heat reaches the curtain, it is already through the glass and inside the room. Curtains help with glare. They do not help with heat.

The argument, in one sentence

Block the heat outside the glass, run the fan with it, and stop fighting the geometry of your house. Everything else is a thermostat trick.