Los Angeles surface temperature, Glynn Hulley, ECOSTRESS, NAPA JPL, August 14th 2020

27 tips to protect your home, city, and your self from extreme heatwaves

Heatwaves are getting more extreme every year, having dramatic consequences for human health, the environment, and the economy. Here’s what you can do to avoid getting cooked next summer.

Recent heatwaves have been the most extreme they’ve ever been. Searing temperatures in California reached up to 120F and took such a toll on the grid that there wasn’t enough electricity because all the power had been used up by millions of air conditioners. Stage 3 critical alerts for potential power grid failure were issued by the California ISO for the first time in eleven years and electricity utilities issued rolling blackouts across the state across multiple days.

How to Protect Your Building From Heat Waves

1. Paint your roof white

There’s a special coating you can use called a reflective roof coating that is specially designed with molecules that reflect the run’s rays. It’s just like regular white paint but with added reflective sparkle. You can see on the thermal image below how a reflective coating can reduce the temperature of your roof by 27 degrees C.

Surface temperature cooling of up to 27 °C (32%) due to increased UV reflectivity of white painted surface. Image by Glynn Hulley, NASA JPL.
From Reducing Urban Heat Islands — a compendium of strategies, Cool Roofs, EPA

2. Install a green roof or green wall

Green roofs work even better than white roofs at protecting buildings from summer heat. The water content of the plants and soil used in the green roof provides a thick insulation layer and the plants add evaporative cooling because as water in the leaves evaporates, it takes heat with it.

From Reducing Urban Heat Islands — a compendium of strategies, Green Roofs, EPA
Modular green roof trays by Greening Solutions.

3. Rig up a porch mister

No AC unit will cool you as efficiently as simple, low-tech H20. Water is powerful like that. There’s a nifty gadget called the porch mister that everyone should know about. It sprays misted water from the eaves or overhangs of your house (or wherever you install it) and cools the building envelope from the outside. Porch mister kits sell on Amazon for under $50 or you can go for this fancy 40 nozzle kit for $1,995.

Porch misters From Amazon and Cool Off.

4. Plant a shade tree

Trees are a trifecta of cooling power. They provide shade from the direct sun, are full of water which stabilizes the surrounding temperature, and their leaves do evaporative cooling through a process called evapotranspiration. Your local energy utility or tree planting groups such as California Re-Leaf, Friends of the Urban Forest, or Canopy may even offer free trees and tree-care support.

5. Grow a shade vine

Shading with plants is one of the easiest and most natural ways to cool your home — not to mention the prettiest! Amazon sells ready-made trellis parts you can easily attach to a wall or fence — or make a stop at Home Depot — they may even sell ready-grown vines. This shading by architect Hideo Kumaki is particularly stunning.

Shading on residential buildings.

6. Install a pond or water feature

Harness the cooling power of water by installing a pond or water feature. Thermal images show how much cooler bodies of water are than just grass or plants alone. Some people have made beautiful ponds out of old bathtubs — or you can buy these ready-made pond liners. Here’s a thermal picture of the birdbath in my front yard. You can see how it’s substantially cooler than the surrounding rosemary shrubs and driveway.

Thermal image of my birdbath on a warm day at 6pm, taken with FLIR One Pro camera smartphone attachment.

7. Install external shades on windows that get direct summer sun

External shades are an easy low-tech way to keep the sun from cooking your home. You can install proper outdoor window shades, like these heavy duty solar shades, or if you are renting or not ready for the investment, have a look at this inexpensive reflective shade cloth you can hang on the outside of any window to reflect the sun.

Heavy-duty outdoor solar shades. It even comes with remote control!

8. Replace or cover exposed asphalt

Do have an exposed asphalt driveway or a lot of paved surfaces? The best option for cooling your property is to dig up the paved surface and replace it with plants or a grass paver. Grass pavers provide the structure of a paver while letting the grass grow through.

Permeable grass pavers

9. Put in roof insulation

If you don’t already have roof insulation, it can be one of the easiest ways to reduce your indoor heat in summer (and also keep you warm in winter). Jump on Yelp and get a quote from a roof insulator near you.

10. Install a cool roof

Next time you need to replace your roof, chose a cool roof tile or shingle. Cool roof products are specially designed to reflect the sun’s rays away from your roof. Ask your roof contractor about cool roof options and chose a high rated product from the Cool Roof Rating Council directory.

A cool roof reflects 80 percent of the sun’s energy.

11. Install an indoor water tank

You know how it’s always cooler near the beach? You can simulate the same cooling effect by making an entire wall in your house filled with water. How? There are several companies that sell water tanks in the shape of a wall that can be visually integrated with your home and landscape. See these examples on Pinterest.

Waterwall House in Melbourne Australia integrates water tanks into the entire building facade. Slimline water tanks used as a wall.

What cities can do to cool down

12. Paint roads white

It’s almost always black asphalt roads and parking lots that come up baking hot on thermal images we’re using on urbancanopy.io. Roads are some of the main contributors to the urban heat island effect. This effect can be mitigated though, by painting roads with a special coating called Cool Seal. Los Angeles has been experimenting with painting roads with this reflective coating which (in the image below) was shown to cool the road surface by 12 degrees C.

Los Angeles painting roads with Cool Seal.
‘Cool’ road with CoolSeal paint is up to 12 °C (17%) cooler than regular asphalt. Image by Glynn Hulley, NASA JPL.

13. Add more micro-parks and green space

Cities are covered in small urban spaces that can somewhat easily be converted into green (that means living) infrastructure by creating a mini-park called a “parklet” or “pocket park.” Have a look at this Pinterest page for inspiration.

An interesting example of greening a “dead” space. Pocket parks in NYC.
Each blue spot on this thermal map of Los Angeles is a park or grassed area. The large blue region is the Balboa Lake and Golf Course. Image by Glynn Hulley, NASA JPL.

14. Add more urban shade trees

Trees, trees, trees! Trees are the best way to keep a city's temperature down. Support local urban tree planting organizations like Canopy, Friends of the Urban Forest, California Re-Leaf, Tree People, and Arbor Day Foundation. Get to know your local urban forestry organizations (most cities have one) and support them through volunteering, donating, or helping these organizations get more project funding. You can help target hot areas by looking up your city on urbancanopy.io and looking out for the hot spaces and then approaching those properties to plant a tree.

15. Target parking lots for trees, shading, and light surfaces

Every thermal map we look at on urbancanopy.io reveals the same deathly hot spots — parking lots — usually big ones surrounded by box stores. Asphalt parking lots need trees, shading (which can have solar panels) and they need to painted with a reflective coating. All cities should consider a policy that restricts exposed black asphalt and encourages parking spaces like the images below in Strasbourg that are light-colored with lots of green cover and trees.

Zenith Strasbourg
Examples of how parking lots can be green. Studio NAB Carparks 2.0.

16. Encourage green infrastructure like green roofs, green walls, shade trees, and permeable paving with rebates and incentives

We’re only going to get on top of extreme urban heat by blanketing cities in vegetation — and we need cities to encourage building owners to add more of these green surfaces. Cities can encourage small projects like individual green walls and roofs, as well as ambitious creative use of urban space such as the High Line in NYC that repurposed an old suspended railway line into a vegetative public walkway.

NYC’s High Line — a suspended rail bridge turned into public green space.

How to cope with extreme heat without AC

17. Drink ice water throughout the day

Keep sipping a large bottle or jar of ice water. Staying hydrated is key to keeping your body temperature regulated and avoiding heat fatigue and heatstroke. Keep your refrigerator stocked with water and ice cubes.

Photo by Ethan Sykes on Unsplash

18. Use a mist spray fan

A spray mist fan is the simplest way to stay cool. Amazon sells small battery-powered misting fans you can carry in your purse or car. Water mist will cool you faster than AC because water molecules absorb heat out of your body as they evaporate from your skin.

Wearable misting neck fan.

19. Wear a moist cooling scarf or wet towel

The most direct way to cool down is to use water instead of AC. Get a towel or some fabric and wet it, and wrap it around your neck, head, or shoulders. There hasn’t yet been great innovation in cooling garments you can wear, but there are few options on Amazon and Etsy.

Cooling necklace that you store in the freezer, Koolgator cooling scar, and me in a wet towel.

20. Plan to get out into nature or the beach on hot days

If you know a hot day is coming and you don’t want to swelter at home or rely on the environmental burden of AC, plan to spend the day outdoors at the park, forest, or beach. Mobile solar products like the Sunbox (an easy portable solar panel and battery kit) can help you generate solar power for your laptop and phone while you work at the park or beach. Working from outdoors has never been so doable.

Work outside where it’s cooler with a Sunbox light-weight solar panel and battery.

21. Hose down your porch, walls, and windows

You can create an evaporative cooling envelope around your house — simply by hosing down the outside walls, deck, and windows every hour or so. I’ve done this on extremely hot days and it worked to immediately bring the indoor temperature back to the tolerable range.

Thermal image of my deck on a hot day after I hosed a section with water. The wet section became instantly 20.9 degrees C cooler.

22. Put a wet towel over indoor furniture and warm surfaces

All the items in your house absorb heat: sofas, tables, chairs, beams, the floor — it all heats up. A dark piece of furniture can store a lot of heat during a heatwave. You can grab some towels and wet them, wring them out, and place the damp towels over furniture to create an indoor cooling canopy. It sounds weird but it really works get the heat out.

23. Spray the indoor walls

This might sound weird, but it works. The inside walls of a home can hold a lot of heat during a heatwave. Spraying a light misting of water directly onto your indoor walls can create an evaporative cooling layer. Just get a spray bottle and lightly spray the surfaces near where you will be hanging out. It will dry up and take a lot of heat with it.

Thermal image of spraying a wall on a hot day. It reduced the surface temperature by 3.8 degrees C.

24. Put up silver reflective mesh or shades on windows that get direct sun

I stayed in a room a couple of years ago that got such intense afternoon sun through the window it felt nearly as hot as a frying pan. No regular curtain could keep that kind of heat away. I purchased a couple of those reflective car dashboard protectors and stuck them to the outside of the window. There are several types of reflective shade cloth options on Amazon you can use on outdoor surfaces to reflect that sun.

25. Sit in a cold bath

This might sound extreme, but if you can handle it, submerging in a cold bath for ten minutes will reduce your entire body temperature and you can stay cool for a couple of hours. You can always just hang out in the cool bath for the afternoon with a drink and a book if the world is really cooking out there.

Benjamin Pelton in an ice bath

How to keep electricity use low

26. Install Energy Lollipop

We made this Chrome extension called Energy Lollipop that shows California’s grid emissions in real-time. If you check it on a hot day, you’ll see what AC does to CO2 emissions. You’ll be amazed at how high it gets on hot days, especially in the late afternoon. It’s a powerful motivator to keep your electricity use low on hot days.

The Energy Lollipoo Chrome extension showing California’s grid CO2 emissions

27. Charge your EV in the morning during summer

Once you’ve checked Energy Lollipop for a few days, you’ll immediately see the importance of charging your electric vehicle (if you have one) in the morning. During summer, California’s electricity is pretty clean until about 1pm. Then CO2 emissions keep rising throughout the day until it peaks at about 7pm and doesn’t drop off again until after 11pm.

CO2 over 24 hours by Energy Lollipop

Where to from here?

Extreme heat events are a scary predicament of the future — and they are only going to get worse. However, we can fashion buildings, streets, and cities to not be the victim of global climate change. With some good environmental engineering, nature-inspired urban planning, and energy-saving behaviors, we can transform our cities into thriving green spaces instead of letting ourselves cook like the frog that slowly boils to its death without noticing the temperature rising.

Environmental Engineer | “Fitbit for the Planet” Designer | Author of How to Save the World | Join the movement at katiepatrick.com and energylollipop.com

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