Your AC should be going full blast this morning, utility experts say. Here’s why

State energy experts are issuing an unusual request to customers to help electric companies avoid running out of power during this week’s intense triple-digit heat wave:

Turn your air conditioner on overnight and through the morning to cool your house as much as possible before peak heat hits in the afternoon.

Then, at 1 p.m., adjust the thermostat to 80 degrees or higher, and hope that you have pre-cooled your house enough so that you can survive the late afternoon and evening comfortably – and help utility districts avoid running out of electricity during their real crunch time, which is late afternoon and early evening.

That advice, from the Sacramento Municipal Utility District, was echoed this week by Pacific Gas & Electric, which is at greater risk in the next few days of suffering forced blackouts.

Unlike Pacific Gas & Electric, which was forced to impose rotating power outages on Friday and Saturday nights, the Sacramento Municipal Utility District has so far avoided such outages and says it expects that to continue this week.

To do so, SMUD officials are asking people to engage in a “high-low” strategy with their air conditioners: Set the thermostat low each evening after 9 p.m. and try to cool your house as much as possible until about 1 p.m. the next day. Then, turn the thermostat up to avoid stressing the community’s grid system.

How low should you go? SMUD officials say that is up to you. The company has enough power available in the mornings to handle higher usage. Solar power, in particular, is at its peak availability mid-morning through mid-afternoon, before waning considerably toward late afternoon.

“The goal in any kind of cooling strategy for personal comfort is to keep the building from heating up in the first place,” SMUD spokesman Chris Capra said. “Most homes built in California the last 20 years have been built really tight (energy efficient). Many of those homes can be pre-cooled and are tight enough to retain that cool air” in the afternoon as outside air temperatures rise.

In Sacramento, temperatures peaked Sunday evening at 4:30 p.m. and SMUD’s customers’ power usage peaked at 5 p.m. PG&E customer usage peaked Sunday at 5:30 p.m.

SMUD has avoided being forced to institute premeditated power outages since 2000. But officials say this week’s high temperatures could put the company at risk of doing so if afternoon usage is high and some unforeseen event occurs, such as loss of use of a transmission line.

SMUD officials said they learned a lesson in 2006, when the utility set a peak load record during two weeks of 100-degree plus temperatures. In that case, some major businesses were not cooled over the weekend, so when workers returned on Monday, the building air conditioners could not sufficiently recool the buildings, even as local energy use hit all-time highs, Capra said.

PG&E, which provides electricity to much of Northern California, has issued similar advice. According to PG&E, users should pre-cool their homes in the morning, then raise the thermostat to 78 degrees after noon.

PG&E officials warned on Monday, however, that they likely may have to shut power for one or two hours on Monday night and again Tuesday evening if power demand threatens to exceed available electricity supplies.

SMUD has energy-saving tips on its website. Here are some cooling tips:

Reduce use of all household electrical appliances between 1 p.m. and 9 p.m.

In the summer, use fans and close blinds on windows that get direct sun.

Swap out light bulbs for LEDs.

Use a programmable/smart thermostat to help control HVAC and to help pre-cool your living space.

Turning the temperature up just 2 degrees, can save 5-10% on cooling costs.

This story was originally published August 17, 2020 at 10:06 AM.