May 29th, 2025
Hey team, and welcome back to one5c! At the peak of COVID, I convinced my building to grant an exception to their (very reasonable!) temporary ban on outside contractors. Why? So I could bring in an electrician to install ceiling fans. It was the first steamy season that I’d been in my apartment consistently at midday—and it was brutal.
With sweet, breezy relief wafting down from above my desk, the team I was managing at the time eventually started to joke about how much I’d bring up my new fans. I couldn’t help it: I loved the comfort, but also that they helped me ease up on the AC, which is one of the most impactful things any emissions-minded person can do in the dead of summer. But fans are only one of many ways we can dial back our use of artificial chill, which is why we decided to recirculate (😉) our slate of tips for keepin’ cool ahead of those hot months. —Corinne
HOW TO KEEP COOL WITHOUT BLASTING THE AC
By Shreya Agrawal, additional reporting by Audrey Chan
On sweltering days, the temptation to crank the air conditioner can be as hard to resist as the siren song of the ice cream truck. But finding ways to keep your home cool without AC can ease both energy bills and emissions. In the U.S., AC alone accounts for about 17% of a home’s electricity consumption, and the average utility bill can jump by 8% as temperatures climb between June and September.
Blasting cool air from a conventional condenser is also one of the biggest contributors to greenhouse gases. About 3% of global emissions trace back to AC, more than those generated by the airline industry. And, as human-caused climate change spurs more frequent and intense heat waves, demand for indoor chillers could triple by 2050, according to a 2023 report from the United Nations.
Even when the temperature outside makes shutting off AC a hard “no,” it is totally feasible to dial down the thermostat a few notches. It might not always be possible to physically lower the temperature of your home, but making it feel cooler is. Doing so comes down to two things: harnessing the physics of airflow and heat transfer, and leaning into tactics that leverage your body’s natural cooling system. Many of these tricks are especially handy for renters looking to make their homes more efficient.
1. Block sunlight
The U.S. Department of Energy estimates that about 76% of the rays that hit your windows become heat. Keeping panes covered during the day, especially when the sun is at its hottest, can reduce your need for a cooling aid.
Blackout treatments or blinds might seem like the most-obvious move here, but there are options that won’t make you live in darkness. Peel-and-stick solar film, for instance, can block up to 78% of the sun’s warmth from entering a dwelling; in one case study, homeowners saw a temperature drop of more than 10 degrees F. Cellular shades, whose folds form an internal honeycomb pattern that acts as an insulator, can cut unwanted solar heat by up to 60%. Other coverings, like slat-style louvered blinds or rolling roman shades, can also help, though they’re less effective.
2. Create a cross breeze
Keeping air moving doesn’t necessarily lower the mercury, but it does create a chilling sensation as it helps sweat evaporate off the skin—your body’s natural cooling mechanism. If it’s decent enough outside to have the windows open, cross-ventilation can let you feel the breeze, while also pulling cooler air inside and pushing warmer air out.
To generate a breeze, open a door and/or window on opposite sides of your home, creating an inlet and an outlet. Then position fans—either box, floor, or table—to direct air from one side to the other. This will work best if you take advantage of the natural tendency for hot air to rise (aka convection): Place the inlet at a lower level than the outlet, which can be as simple as lowering the top sash of a window instead of raising the bottom. One study conducted in India found that good cross-ventilation can have a cooling effect of around 11 degrees F at the hottest point in the day.
3. Optimize your ceiling fans
Like cross-breezes, a gentle waft of air coming off a ceiling fan can help sweat evaporate more quickly. While the level of cooling depends on how fast the air is moving and how humid it is, a fan can let you adjust the thermostat up by 4 degrees F. Most fans are bidirectional, so glance up at yours and make sure it’s spinning counterclockwise, which creates a downdraft. If it’s going the wrong way, turn it off and find the switch that reverses the spin.
A wobbly or dirty fan is also an inefficient one. Dusty blades may not slice through the air as well as clean ones—and they’ll also fling crud around the room. Add wiping down the blades to your cleaning routine, and while you’re up there make sure to check and tighten up any fasteners. We’ve got the guide on what to do if your ceiling fan isn’t acting up to scratch.
4. Keep humidity in check
On steamy days, the air is simply too saturated for sweat to evaporate efficiently, making you feel even hotter. When it’s damp out, a dehumidifier can be your hero. These appliances condense and collect water vapor, and then release drier air back into the room. (According to the EPA, the ideal indoor humidity is between 30% and 50%.) Another reminder: If you have a bathroom fan, be sure to run it to dissipate the effects of steamy showers. Lower humidity will not change the temperature of your home, but can make it seem cooler.
5. Use appliances wisely
Appliances like ovens, dishwashers, and refrigerators need a lot of energy and generate a lot of heat as they do their jobs. In some cases they are responsible for more than 16% of the heat in a home. While you can’t do much about your refrigerator, make sure to use things like ovens, dishwashers, and clothes dryers during cooler hours—if you turn them on at all.
You can, for example, line-dry your clothes, opt to grill, or tap another alternative cooking method like an induction burner. Baking a pie in the oven, for instance, could raise the temperature in your home by 1 to 10 degrees F, while using a smaller appliance like a toaster oven or air fryer will do less to kill your chill. One more tip: Unplug devices when not in use––they can generate heat, even on standby.
Product Review
The best beeswax wrap
A darling of sustainable kitchens, beeswax wraps offer a simple alternative to plastic for keeping foods fresh. Check out our top pick.
THE ROUNDUP
IN THE NEWS THIS WEEK
Investing in sustainability raises revenue for almost 80% of food and agriculture businesses, according to a new study from NYU and Deloitte. In addition, about 74% of firms found that their costs were slashed by at least 2% after investing in strategies like food waste reduction and ecosystem restoration.
The ‘warming stripes’ graphic, which has translated global surface temperatures into colorful bands since 2018, just got a big update. A team of scientists, including creator and climate scientist Ed Hawkins, has added details to the iconic chart to demonstrate the drastic changes in the ocean and upper atmosphere.
PepsiCo is dialing back its commitment to cutting total emissions 40% by 2030, reports FoodDrive. The food giant, responsible for 5% of plastic pollution globally, is also tempering its ambitions around packaging waste, including nixing a program to scale reusable packaging. The company says it’s centering attention on regenerative agriculture goals—a sustainability solution primed for greenwashing.
There’s a 70% chance that 5-year average warming between 2025 and 2029 will be more than 1.5 degrees C, according to a new report from the World Meteorological Association. This likelihood is a big jump from last year’s forecast (47% for 2024–2028) and the one prior (32% for 2023–2027).
Boston is the best city in the U.S. for access to nature and green spaces, according to a TimeOut survey of 18,500 locals. Greenery is a potent mitigation tactic for climate change: It keeps temperatures low, helps reduce flood risk, and boosts air quality. The first-place winner, Medellín, Colombia, saw temperatures drop 3.6 degrees F after developing its iconic green corridors. Check out where else made the list.
Copyright © 2025 one5c. All rights reserved.
Logo design by Claudia De Almeida
Questions? Feedback? Contact the editors at one5c@one5c.com.
Our mailing address is:
3112 Windsor Rd, Ste A-391, Austin, TX 78703