BPA test finds night setback can trigger electric‑resistance backup and raise morning peaks

BPA researchers ran a mid‑project thermostat setback test in which January was operated with no setback and February used night setback on 14 central‑duct homes. The project manager said the result was that setback sometimes produced higher energy use and significantly larger coincident morning peaks because electric resistance backup activated during morning warm‑up.

"Leave your thermostats at the same setting, so that allows on cold days, allows the heat pump to run essentially run all night to keep that house at that level," the project manager advised, summarizing the implication for heat‑pump operation and program design. The team recommended reconsidering traditional night‑setback guidance for dual‑fuel systems (heat pump plus electric resistance) because recovery from a low setback can cause rapid resistance use and increase grid demand during morning peaks.