Another round of heat is headed our way, and your air conditioner is about to work overtime.

Astacio-Sila, an HVAC company with headquarters in Norwalk sees an increase of calls during stretches of extreme heat. The company's serves Westchester County in New York, up to Danbury.

"We could have an influx of up to 700 calls a day," said Michael Bennett, general manager at Astacio-Sila.

Bennett said annual tune-up are recommended for HVAC systems to make sure they continue to function during extreme heat.

Their most common calls are for leak issues or a system that's failing to maintain its temperature.

"When it's 100 degrees, if there's something wrong, that's when it's going to break down," Bennett said.