(Bloomberg) -- More than a third of Americans are facing a scorching heat that threatens to topple temperature records and stress power grids as homeowners and businesses crank up air conditioners to seek relief. "There is still a lot of heat through the Plains for the first half of the week. "Either way, there is going to be a lot of heat somewhere through the week," he said. Across the country, 94 daily high temperature records may be broken, threatened or tied through Sunday, the agency said. The heat is taxing power grid operators across the US.