Can Housing Save Us from the Heat?

If we continue down this road, our homes may be the last line of defense.

It occurred to me, as I watched Arizona facing down 110 degree temperatures for two straight weeks, that we might be witnessing the beginning of the end. 

How hot can it get, I wondered, before human beings simply can’t survive? I found a recent study that suggests that at 122 degrees F, a person may survive prolonged exposure, but “it’s nasty.” Go higher than that for any length of time, and our bodies fail. Along the way, we get more aggressive, depressed and anxious.

Of course, 122 degree survival may be overly optimistic. In many places, the effects of extreme heat take effect even sooner, thanks to the dew point. In other words, 100 degrees in Washington, D.C., feels more soul crushing than 110 degrees in Phoenix. 

Once temps hit 130 degrees, it’s lights out for most mammals, whatever the humidity and dew point. Now might be a good time to point out that, according to Nature, “Of the 4 billion species estimated to have evolved on earth over the past 3.5 billion years, 99 percent are gone.”

Could parts of the U.S. hit 130 or 140 degrees or higher on a regular basis? Scientists are not sure.

No modeling, not even AI, has been able to synthesize all of the myriad data required to answer that question. How much weight do we give the ocean’s finite ability to absorb heat? How does increasing methane pollution change the equation? Don’t forget to include before and after data on the total square miles of reflective ice sheets, melting by the day? Also, will particulates from wildfires make things worse?

We’re left playing defense, creating buildings that will serve as sanctuaries from the heat. We have the cooling technology, but the more inefficient the home, the more power it needs. Only 2 percent or fewer of existing U.S. homes operate at net zero efficiency. That means we’ll need a massive, pulsing power grid, straining under its fossil-fuel turbines, to keep 98 percent of our homes cool.

We have the right technology to defy the heat in our homes, but will we have enough reliable grid power to keep them habitable? Texas logged 720 hours of localized power outages in 2022. Louisiana was second worst with 697 hours down. Both States face extreme risk from heat waves.

Clearly, over the coming years, we need to vastly reduce housing’s dependency on centralized power (unless it’s coming from solar or wind). For existing homes, that means more and better insulation and cool roofs. 

For example, we’ve written about how 1-inch R-6 polyisocyanurate sheet foam on top of a waterproofing membrane and OSB roof deck can lower the surface temperature of the attic side OSB by 30-40 degrees. Homes should also get solar-ready wiring upgrades, low-E windows, and an HVAC upgrade to high efficiency heat pumps and hybrid or solar hot water heaters. For new homes, it’s all of the above, with a “net zero” benchmark for every project plan.

Green Builder’s 20-year mission has become a lot more urgent. We’re not waiting for builders to catch up. We’re creating a set of Environmental, Social and Governmental (ESG) guidelines called ESG for Building to track real change and overcome greenwashing.

As an industry, we can do our part, but we can’t change human behavior. That has to come from within, and maybe it’s bigger than us. Let’s stay focused on what we can do: buy millions of Americans some time, a safe place, perhaps to ride out the coming climate catastrophe for a while, maybe for a long while. Maybe that will give us all time for a mental reset, about the destructive, wasteful practices that we have the power to change.