Do you live in east/mid Texas? That sounds like some super great insulation if you are only accumulating 2 degrees an hour during a hot humid Texas summer.

My house in Dallas only rose by about one degree per hour during the day when the A/C was off, even on the hottest days. It was pretty well-insulated, and the large trees around it helped.

> humid Texas summer

This is probably the warped idea of "humid" I got from growing up in South Florida, but Dallas was rarely ever humid.

Dallas is relatively humid, but not Florida, no.

It also doesn't have the constant sea breezes and incidental rain that most of Florida enjoys.

Build your houses out of stone rather than wood, and they'll have a 10+ tonne thermal mass. Just a few inches of insulation around that on all sides, and the temperature barely varies day to night.

Houston is as humid as it gets though.

Similar latitude actually. My house is concrete block though so it tends to resist temperature change a bit.

Also keep in mind large buildings will resist temperature changes even better than houses due to their size. Less surface area per volume.

Good insulation is a great investment for any home. Keeps your house cooler in summer, warmer in winter, dramatically reducing your energy needs in both cases.

Our house went from 78 to 85 in 48 hours with the AC completely off. With highs over 100. We have an old house with basic insulation upgrades.

I'd expect it is a combination of insulation and thermal mass.

Time of use rates will even get the residents to do it (precool) themselves.

Do any of the smart thermostats have this function (tying in with rates?)

Yes they do. Austin Energy has the Rush Hour rebate program that precools your house before peak demand. It’s compatible with several programmable thermostats. It’s an opt-in program and you can override your thermostat if you want. Austin’s rates don’t change with demand, but they are tiered and increase the more electricity you use per month.

My Nest is signed up with my local power provider. In the summer, they turn up my temp a couple degrees from 2-6pm a couple times a month.

There's a pre-cool from 1-2 where they drop the temp, and if I leave it alone for the entire four hours, I get $5 off my power bill that month.

My parents (who live in Texas) get a rebate like this from their electricity company, which surprised me by even having an option to do it manually without a Nest-style internet-connected thermostat. If it's a day that the company wants reduced peak usage, they text+email you that you can get a rebate if you reduce usage during a certain set of hours. They judge whether you did or not by measuring your usage during those hours against your historical usage on similar-temperature days, so you can get the credit just by turning up your thermostat manually for a few hours. (This does require a new-style meter that reports hourly usage.)