As millions of Americans prepare for another brutal heatwave, it’s now harder to find information about ways to stay cool while saving energy and keeping utility costs down.

At least 1,662 department of energy webpages offering guidance on protecting the electrical grid during heatwaves have gone dark as of 3 July, according to a Guardian analysis of a list of deleted URLs provided by researchers at the Internet Archive, a non-profit that hosts a repository of more than a trillion archived webpages.