Millions of Americans are currently dealing with a heat wave across the US, so staying cool is important. There are many ways to deal with the scorching heat, and the good news is that quite a few of the tools that can help are on sale for Prime Day. These range from the obvious Prime Day air conditioner and tower fan deals, but you can also find discounted cooling sheets and even a mattress that can help transfer your body heat during the night for better sleep if you are in fact sleeping and not obsessively tracking our Prime Day liveblog. We test products year-round and handpicked these deals. We'll update this guide periodically throughout the sale event.

One little-known home and retail automation startup might seem like an unlikely candidate to help combat the ongoing pandemic. But its founder says its technology can do just that, even if it wasn't the company's original plan. Butlr, a spin-out of the MIT Media Lab, uses a mix of wireless, battery-powered hardware and artificial intelligence to track people's movements indoors without violating their privacy. The startup uses ceiling-mounted sensors to detect individuals' body heat to track where a person walks and where they might go next. The sensors can turn on mood-lighting or air conditioning when it detects movement, help businesses understand how shoppers navigate their stores, determine the wait-time in the queues at the checkout, and even sound the alarm if it detects a person after-hours.