Cool Evenings in Twin Falls: Opening Your Home Up at Dusk

A Twin Falls summer day can feel long, with about 210 sunny days a year according to the Twin Falls Area Chamber of Commerce and July highs that average around 89 degrees. Then the sun drops, the air cools, and the evening arrives with a very different feel. For anyone who likes to open the house up at the end of the day, that change is worth planning around.

The local climate makes this more than a matter of taste. The temperature difference between a Twin Falls afternoon and the night that follows is larger than many people realize, and federal building guidance has a name for the idea of using it: ventilation cooling.

A Big Swing Between Day and Night

NOAA's 1991 to 2020 climate normals for the Twin Falls airport station, as compiled by two climate data sites, put the average July high in the high 80s and the average July low in the mid to upper 50s. Across June through September, the average gap between the daytime high and the overnight low runs from about 28 to 33 degrees. June nights average close to 50 degrees, and by September the average low is in the mid to upper 40s.

In plain terms, the house can be warm at 5 p.m. and the air outside can be pleasantly cool by 9 p.m. That is the window many families use to open doors and windows and let the day's heat out.

What Federal Guidance Says About Cool Nights

The U.S. Department of Energy's Building America program publishes a guide called Measure Guideline: Ventilation Cooling, prepared by Springer, Dakin and German in 2012. It explains that ventilation cooling "can be effective in a variety of climates that experience significant outdoor diurnal temperature variations." As a rule of thumb, it points to places where average nightly lows are at or below 65 degrees and the average monthly difference between the daily high and low is 20 degrees or more.

Twin Falls summer averages sit comfortably inside both numbers. The DOE's Energy Saver pages describe the same idea in everyday terms, calling it night flushing, which uses cooler night air to cool a home and its thermal mass, and noting that it works best in climates with cool nights. These are general guidelines for buildings, and results depend on the house, the weather and how it is used, so this guide does not promise a specific saving. It simply shows that the habit of opening up on a cool evening has a sound basis in Twin Falls.

What Idaho Power Suggests

Closer to home, Idaho Power, the utility serving much of southern Idaho, offers summer tips that follow the same rhythm. Its advice is to "open your windows at night or in the morning to let cool air in," and to close windows and blinds during the day, especially on the east and west sides of the house. Shade through the hot afternoon, open up when the air cools: that is the routine a Twin Falls summer rewards.

Where Retractable Screens Fit

The catch with an open window or door at dusk is that the evening is also when flies, mosquitoes and wasps are active. University of Idaho Extension notes that "in late summer and early fall yellowjackets often keep people from enjoying parks, picnics, and other outings," and flies and mosquitoes are part of the Magic Valley summer too. A retractable screen lets the house stay open to the cool air while the insects stay outside.

Phantom describes this use on its own project pages, saying that cross ventilation during the morning and evening hours can reduce the need for air conditioning in summer. Those are manufacturer statements without measured figures, so they are best read as a description of how the screens are meant to be used and not as a promise of results.

On a door, a gentle press releases the screen as it glides smoothly along the track, and when you are done it retracts into its housing and leaves the doorway clear. Phantom builds door screens for single and double patio sliding doors, swing doors and French doors, and each one is custom-built to the size of the opening. The guide on sliding door screens in Twin Falls covers the size, mesh and color decisions in more detail.

Windows can do the same job. Phantom builds window screens for single-hung, double-hung, casement, sliding and awning windows, up to 84 inches wide and 90 inches high. They retract into a slim housing, so the glass stays clear when you are not using them. Opening a window on the shady side of the house and one on the opposite side lets air move through the rooms in between. The guide on retractable window screens for Twin Falls homes walks through the window types and mounts.

Choosing Mesh for Evening Air

For evening ventilation, insect mesh is the natural choice. Phantom lists its 20/20 mesh at about 43 percent openness with up to 57 percent sun and UV blockage, and its 18/14 mesh at about 56 percent openness with up to 44 percent. The openness figure is the share of the mesh that is open, which is part of why these meshes keep the view clear and let air pass through.

For a west-facing door or window that takes the hard afternoon sun, solar mesh is worth a look during the day. SunTex 80 is listed at 25 percent openness, with up to 75 percent sun and UV blockage and up to 80 percent heat blockage. These are manufacturer ratings given as "up to" figures, so results depend on the mesh and the exposure. The guide on solar mesh for high-desert sun goes into the tradeoffs in detail.

A Simple Evening Routine

The pieces fit together easily. Shade the sunny sides of the house through the afternoon, as Idaho Power suggests. When the air outside cools, open the doors and windows on opposite sides of the house and let the screens keep the insects out. Leave them open through the evening, whether you are cooking, hosting or just sitting down after a long day. The guide on hosting outdoors in Twin Falls covers how that works when guests come over.

Housings and tracks come in standard powder-coated colors, wood grain finishes, and custom color matching from a swatch you supply, so the screens blend into your trim and look like part of the home.

Frequently Asked Questions

Q: How much do Twin Falls evenings cool down? Using NOAA's 1991 to 2020 normals for the Twin Falls airport station, the average gap between the daytime high and the overnight low runs from about 28 to 33 degrees from June through September.

Q: What does the Department of Energy say about cooling with night air? Its Building America guide says ventilation cooling can be effective in climates with significant day-to-night temperature differences, and points to average nightly lows at or below 65 degrees and a monthly difference of 20 degrees or more as a good indication.

Q: What does Idaho Power suggest? It suggests opening your windows at night or in the morning to let cool air in, and closing windows and blinds during the day, especially on the east and west sides.

Q: Which mesh works for evening ventilation? Insect mesh is the usual choice. Phantom lists 20/20 at about 43 percent openness and 18/14 at about 56 percent openness.

Q: Can I screen both doors and windows? Yes. Phantom builds door screens for single and double patio sliding doors, swing doors and French doors, and window screens for single-hung, double-hung, casement, sliding and awning windows.

Want to make the most of Twin Falls evenings? Contact Phantom Retractable Screens of Twin Falls for a free, no pressure consultation. We will look at your doors and windows, show you mesh and color samples, and recommend a setup that fits the way you live. Screen mesh is not included under the component warranty, but it can always be repaired or replaced if needed.