With temperatures soaring on Sunday, 673 homes in the Mildenhall area could not even turn on a fan as a fault in an underground cable cut electricity.
UK Power Networks says the powercut struck at 10am and its engineers worked as quickly and as safely as possible to restore electricity supplies.
A spokeswoman said: “The majority of supplies were restored by 11.45am yesterday, with the remaining supplies restored during the early hours of this morning.
“We understand how difficult it is to be without power and apologise for any inconvenience caused.”
Temporary generators were connected to powerlines in outlying areas.