How to keep cool while saving energy

Summary

Life Kit Podcast Summary: "How to Keep Cool While Saving Energy"

Life Kit, hosted by Marielle Segarra, explored practical ways to stay cool during the summer while minimizing energy consumption and combating climate change in its episode titled "How to Keep Cool While Saving Energy," released on June 23, 2025. Featuring insights from NPR's climate solutions correspondent Julia Simon and Dorit Aviv, an assistant professor of architecture at the Weizman School of Design, University of Pennsylvania, the episode offers five actionable tips to help listeners maintain comfortable indoor temperatures efficiently.

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Introduction

Marielle Segarra opens the episode by sharing her personal experience with the summer heat in New York, noting temperatures soaring to 98 degrees. She highlights the common reliance on air conditioners (ACs) to stay cool but points out the significant electricity consumption associated with their use, which contributes to climate change. To address this, she introduces Julia Simon, who delves into eco-friendly cooling strategies.

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Tip 1: Open Windows for Natural Ventilation ([00:58])

Julia Simon begins with the simplest energy-saving tip: open your windows. She explains that sometimes the indoor temperature can be hotter than outside due to heat produced by electronics and daily activities.

"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." — Dorit Aviv ([01:06])

Marielle questions the effectiveness of this method across different climates, to which Julia responds by emphasizing its best use during cooler times of the day, such as early mornings and evenings. She introduces the concept of "night flushing," a technique where windows are opened at night to release accumulated heat.

"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." — Julia Simon ([02:11])

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Tip 2: Utilize Ceiling Fans Before Air Conditioning ([02:13])

The second tip encourages the use of ceiling fans instead of immediately resorting to ACs. Marielle admits her interest in installing ceiling fans after hearing Julia's recommendation.

"Ceiling fans. I actually should get one." — Marielle Segarra ([02:23])

Julia and Dorit advocate for ceiling fans due to their energy efficiency. Dorit highlights their advantage over ACs:

"They're so much more energy efficient than air conditioners." — Dorit Aviv ([02:29])

Additionally, Julia references Australian research indicating that fans can reduce energy use and associated greenhouse gas emissions by up to 76% compared to 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%." — Julia Simon ([02:34])

While ceiling fans don't lower the air temperature, they enhance the cooling effect by circulating air, making spaces feel more comfortable without excessive energy use.

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Tip 3: Install External Shades to Block Heat ([03:13])

The third tip focuses on managing sunlight exposure with external shades. Julia explains that traditional indoor shades or curtains primarily block light but not the heat associated with it.

"The sunlight that's coming in, that is bringing in light is also bringing in heat." — Julia Simon ([03:52])

She shares her experience from Vienna, Austria, where she met Sebastian Schublach, who introduced her to external shading solutions. These shades are installed outside the house and can be adjusted manually or automatically to block sunlight before it enters the home.

"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." — Sebastian Schublach ([04:29])

Marielle inquires about the availability of such solutions in the U.S., and Julia confirms that external shades are readily accessible through major shade retailers, often priced comparably to indoor options.

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Tip 4: Seal Cracks and Openings to Prevent Heat Exchange ([05:08])

The fourth tip involves sealing any cracks or openings in the home to prevent unwanted heat transfer. Julia provides a brief physics lesson on the second law of thermodynamics:

"Heat will always try to escape from a hotter region to a cooler region." — Julia Simon ([05:14])

Dorit elaborates on this principle, explaining that both in summer and winter, gaps around windows and doors can lead to significant energy loss or gain.

"So it's actually part of the second law of thermodynamics." — Dorit Aviv ([05:17])

Julia recommends using rubber weather stripping tape around window frames and doors to seal leaks. She emphasizes that these materials are affordable and can be easily purchased at hardware stores or online.

"Buy some tape or rubber. This is called rubber weather stripping tape." — Julia Simon ([05:48])

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Tip 5: Apply Reflective Coatings to Your Roof ([06:09])

The fifth and most ambitious tip is to make your roof reflective. Julia explains that roofs absorb a significant amount of heat from sunlight, which translates into increased indoor temperatures.

"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." — Julia Simon ([06:20])

Dorit advises painting the roof with a reflective color, such as white or silver, to deflect rather than absorb sunlight. This simple retrofit can substantially reduce the amount of heat entering the home, decreasing the need for air conditioning and lowering energy bills.

"If you can paint your roof with a reflective color like white or silver so it absorbs less heat." — Dorit Aviv ([06:57])

She suggests consulting with a professional roofer knowledgeable about reflective paints to ensure effective application.

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Conclusion and Recap

Marielle Segarra concludes the episode by summarizing the five energy-saving tips:

1. Open Windows: Utilize natural ventilation by opening windows, especially during cooler times of the day, to create cross breezes.
2. Use Ceiling Fans: Enhance cooling with ceiling fans before turning on air conditioners to save energy.
3. Install External Shades: Prevent heat gain by using external shades to block sunlight.
4. Seal Cracks and Openings: Improve home insulation by sealing gaps around windows and doors with weather stripping.
5. Apply Reflective Roof Coatings: Reduce heat absorption by painting the roof with reflective colors like white or silver.

Marielle encourages listeners to implement these strategies to create a more energy-efficient and comfortable living environment while contributing to the broader fight against climate change.

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Additional Resources

For more insights on energy efficiency and climate-friendly home improvements, listeners are encouraged to explore other episodes of Life Kit, including topics on significant purchases to lower electricity bills and the benefits of electric cars. Visit npr.org/lifekit for more information and to subscribe to the Life Kit newsletter.

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Credits

This episode of Life Kit was produced by Sylvie Douglas and edited by Neela Banerjee and Meghan Cain. The visuals were crafted by Becky Harlan, with Malika Gharib handling digital editing. Executive production was led by Beth Donovan, supported by Andy Tagle, Claire Marie Schneider, and Margaret Serino. Engineering support was provided by Simon Laszlo Jansen and Marielle Segarra.

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Transcript

[Marielle]

You're listening to Life Kit from npr. Hey, it's Marielle. Summer is finally and officially here. It's going to be 98 degrees in New York for the next couple 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 going to want to 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?

[Julia Simon]

It's very simple. I kind of love it. The tip is open a window. To explain why, I talked to Dorit.

[Dorit Aviv]

Aviv, and I'm an assistant professor of architecture at the Weizman 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.

[Julia Simon]

Things like our computers or cooking or other devices, all of those increase the indoor air temperature.

[Dorit Aviv]

So Dorit says instead of going to the thermostat and lowering your your air temperature on your air conditioner system, you can just open the window.

[Marielle]

Yeah, I'm. It sounds like this advice might work better in some climates than others. More temperate climates. More temperate seasons. Yeah.

[Julia Simon]

I mean, but this actually often works, you know, 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.

[Marielle]

All right. What's your second tip?

[Julia Simon]

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.

[Marielle]

Ceiling fans. I actually should get one.

[Julia Simon]

I'm a big fan of ceiling fans. Dorit is also a big fan.

[Dorit Aviv]

They're so much more energy efficient than air conditioners.

[Julia Simon]

A group of researchers in Australia found that using fans compared to air conditioners can reduce energy use and related greenhouse gases by by 76%.

[Marielle]

And do they actually keep you cool?

[Julia Simon]

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 change 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?

[Marielle]

I do. I have some shades and some curtains.

[Julia Simon]

Are they on the inside or on the outside of your windows?

[Marielle]

See, that's a funny question because I never knew they could be on the outside of my windows.

[Julia Simon]

Well, here's the thing. While here in America, a lot of us have shades or curtains on the inside of the window pane. And 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.

[Marielle]

The sunlight that's coming in, that is bringing in light is also bringing in heat.

[Julia Simon]

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 like a.

[Marielle]

Curtain outside of your window?

[Julia Simon]

Obviously it makes sense because the heat doesn't go in, it stays out.

[Marielle]

Exactly. Okay. And is this available in the US too?

[Julia Simon]

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 U.S. many of the prices are comparable to indoor shades. Sometimes a bit more expensive, but you can find them here.

[Marielle]

Nice. Yeah. Some of my favorite things to do is to bring back inspiration from how other countries do things.

[Julia Simon]

That's what we're all about on the climate desk.

[Marielle]

All right, well, tip number four involves a little physics lesson. I hear it's true.

[Julia Simon]

The lesson goes like this. Heat will always try to escape from a hotter region to a cooler region.

[Dorit Aviv]

So it's actually part of the second law of thermodynamics.

[Julia Simon]

And this is a tip for summer and winter. Let's say it's wintertime. So you're heating your house and it's cooler outside, that heat on the inside will try to escape to the outside. The 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.

[Dorit Aviv]

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.

[Julia Simon]

Those cracks are often near our windows, our doors. So here's the tip. Seal it up. Buy some tape or rubber. This is called rubber 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.

[Marielle]

So. All right, what's your fifth and final tip for us today?

[Julia Simon]

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.

[Marielle]

Because the roof gets a lot of sunlight.

[Julia Simon]

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, to reduce energy use is to coat your roof with a white or silvery color. A reflective roof.

[Marielle]

Okay. So the heat from the sun gets reflected away from the house instead of absorbed inside.

[Julia Simon]

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 that can help reflect sunlight.

[Marielle]

All right, Julia, thank you so much for these tips.

[Julia Simon]

Thank you for having me.

[Marielle]

That was NPR's Julia Simon. To find more stories about housing and climate change, you can go to npr.org climateweek 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 out 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 three, look for shades that you can mount outside of your windows rather than inside. Takeaway 4 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 [e-mail] LifeKit and if you love Life Kit and want even more, subscribe to our [e-mail] lifekitnewsletter. Also, we love hearing from you, so if you have episode ideas or feedback you want to share, email [e-mail] this episode of Life Kit was produced by Sylvie Douglas and edited by Neela Banerjee and Meghan Cain. Our visuals editor is Becky Harlan and our digital editor is Malika Gharib. Beth Donovan is our executive producer. Our production team also includes Andy Tagle, Claire Marie Schneider and Margaret Serino. Engineering support comes from Simon Laszlo Jansen and Mariel Segarra. Thanks for listening.

[Julia Simon]

Sam.