Life Kit - How to keep cool while saving energy

Episode Date: June 23, 2025

As summer heats up, we often crank the air conditioning, which uses a lot of energy. NPR's Climate Solutions Correspondent Julia Simon has five simple and affordable tips to save electricity without sacrificing comfort. We'll cover the science behind the open window versus AC debate, "night flushing" your home and cost-saving home improvement projects to help keep you cool.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

You're listening to LifeKit from NPR. Hey, it's Mariel. Summer is finally and officially here. It's going to be 98 degrees in New York for the next couple of days. So you'll find me hiding inside with the air conditioner blasting. But okay, let's talk about that for a second. That impulse to crank up the AC. Of course, if it's an unbearably hot day, we're gonna wanna do that, and that's understandable. But air conditioning systems do use a lot of electricity.

So when we use them, we are unfortunately contributing to climate change. NPR's Climate Solutions correspondent, Julia Simon, has been covering this. And on this episode of Life Kit, she shares five ways to use less energy at home this summer. The tips are pretty easy and they can help you save on energy bills. Julia, the first tip you have to help us use less energy at home is a simple one, right?

It's very simple. I kind of love it. The tip is open a window. To explain why I talked to Dorit Aviv. And I'm an assistant professor of architecture at the Weizmann School of Design in the University of Pennsylvania. What people don't realize is that the inside temperature is sometimes hotter than it is outside because people inside of buildings produce heat constantly. Things like our computers or cooking or other devices,

all of those increase the indoor air temperature. So Dorit says, instead of going to the thermostat and lowering your air temperature on your air conditioner system, you can just open the window. Yeah, it sounds like this advice might work better in some climates than others,

more temperate climates, more temperate seasons. Yeah, I mean, but this actually often works, early in the morning, this makes a lot of sense at night. There's even this expression called night flushing, when you open the windows to let out all the heat from the day. So the tip is open a window, bonus points, if you can open up two windows on opposite sides

of your space to get a nice cross breeze. All right, what's your second tip? Second tip, if you are needing to cool down your house, instead of turning on that air conditioner, try turning on a ceiling fan if you have one. Ceiling fans, I actually should get one. I'm a big fan of ceiling fans. Dorit is also a ceiling fan if you have one. Ceiling fans, I actually should get one. I'm a big fan of ceiling fans. Dorit is also a big fan.

There's so much more energy efficient than air conditioners. A group of researchers in Australia found that using fans compared to air conditioners can reduce energy use and related greenhouse gases by 76%. And do they actually keep you cool? Well ceiling fans don't lower the air temperature in the same way ACs do. They can provide increased cooling by moving the air around.

If you are in extreme heat and need an air conditioner, of course turn it on. But if you can turn on a ceiling fan or open up a window and still be comfortable, then you can really help the climate and your pocketbook by doing those things first. Tip number three. This one has to do with shades. I'm curious, Marielle, do you have shades in your apartment? I do. I have some shades and some curtains. Are they on the inside or on the outside of your windows? See, that's a funny question because I never knew they could be on the outside of my windows. Well, here's the thing. While here in America, a lot of us have shades or curtains on the

inside of the window pane, if you're trying to stay cool, that doesn't always make sense. And Daniel Barber at Eindhoven University of Technology in the Netherlands says, you might want to think about what that sunlight is also bringing in. The sunlight that's coming in, that is bringing in light, is also bringing in heat. And I feel like we know what he's talking about, right?

The heat comes in with the sun, it stays inside, it heats our space, but there's another option, Marielle. Recently, I was in Vienna, Austria, and I met Sebastian Schublach. He has something called external shading. This is basically a shade that's outside the house going down vertically. You can make it unfold using a switch or it can be automated. So these are your external shading. Do you mind showing us? or it can be automated. So these are your external shading. Do you mind showing us?

Like a curtain outside of your window. Obviously it makes sense because the heat doesn't go in, it stays out. Exactly. Okay, and is this available in the US too? Yes, 100% external shades aren't just in Austria. I called up some of the big name shade stores. They sell them here in the US.

Many of the prices are comparable to indoor shades, sometimes a bit more expensive, but you can find them here. Nice. Yeah, some of my favorite things to do is to bring back inspiration from how other countries do things. That's what we're all about on the climate desk. All right, well, tip number four involves a little physics lesson I hear. It's true. The lesson goes like this.

Heat will always try to escape from a hotter region to a cooler region. That's actually part of the second law of thermodynamics. And this is a tip for summer and winter. Let's say it's winter times. You're heating your house and it's cooler outside. That heat on the inside will try to escape to the outside. The other way is true too. Let's say it's summertime and you're cooling your home. That heat from outside might come in through the cracks when you don't want it to. If you have any cracks, any openings in your buildings, anywhere where it's an easy path for the heat to go through, that's where it will go. Those cracks are often near our windows, our doors.

So here's the tip, seal it up by some tape or rubber. This is called weather stripping tape. You can put it around your window frame to seal the leaks. You can get these things at any hardware store. It's easy to find online and it's often very cheap. So all right, what's your fifth and final tip for us today? Okay, the last tip is the most ambitious, but if you want to make your home more energy efficient, Dorit says one of the best home improvements you can do is to make your roof reflective. Because the roof gets a lot of

sunlight. So much sunlight. The sunlight carries a ton of heat. And when the sun hits your roof, that heat is absorbed through the roof and gets translated into heat inside your home. And here's the thing, this is all made worse because a lot of roofs are covered with black or darker color finishes, which absorb and retain even more of the sun's heat.

So Dorit says one of the easiest home retrofits to reduce energy use is to coat your roof with a white or silvery color, a reflective roof. Okay, so the heat from the sun gets reflected away from the house instead of absorbed inside. Exactly. And then you don't have to cool your house as much. This is all reducing the need for cooling with air conditioners, which means less money spent on your utility bills.

Dorit suggests talking to a roofer who knows about different reflective paints that can help reflect sunlight. All right. Julia, thank you so much for these tips. Thank you for having me. That was NPR's Julia Simon. To find more stories about housing and climate change you can go to npr.org slash climate week. Okay time for a recap. Takeaway one, before turning on an air conditioner, try opening a window or two windows on

opposite sides of the space to get a cross breeze. This works especially well in mornings and evenings when it's cooler outside than inside. Takeaway 2, if you have a ceiling fan, turn it on before you try turning up the AC. They can help a lot. Takeaway 3, look for shades that you can mount outside of your windows rather than inside. Takeaway four, seal up any cracks in your home around the windows or the doors where heat could be sneaking in when you're trying to cool the place down.

And takeaway five, if you can, paint your roof with a reflective color like white or silver so it absorbs less heat. For more Life Kit, check out our other episodes. We have one on five big purchases you can make to lower your electricity bill and another all about electric cars. You can find those at npr.org slash life kit. And if you love LifeKit and want even more, subscribe to our newsletter at npr.org slash life kit newsletter. Also, we love hearing from you,

so if you have episode ideas or feedback you want to share, email us at lifekit at npr.org. This episode of Life Kit was produced by Sylvie Douglas and edited by Neela Banerjee and Megan Kane. Our visuals editor is Beck Harlan and our digital editor is Maulika Grieve. Beth Donovan is our executive producer. Our production team also includes Andy Tagel, Claire Marie Schneider, and Margaret Serino. Engineering support comes from Simon Lazlo Jansen. I'm Mariel Segarra. Thanks for listening.