PORTSMOUTH, Va. (WVEC) -- High temperatures in the 90's and a heat index values pushing up and over 100 degrees: this is not the ideal time to have your cooling systems fail you, but Mark Hinchman with RS Andrews said it happens quite often.

"The units that were still running last year that just kind of just made it through, this is when they do fail. It's been on all day and it's an old heartbeat, old lungs and usually that's when it will kick the bucket," said Hinchman.

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Hinchman also said it's not uncommon for your thermostat to say one thing and do another. That's why he recommends a few tips to keep your air conditioner running smoothly.

"Systems are designed to stay at a temperature and keep that temperature for you as close as they can. We get a lot of people who call in these 100-degree index days and say, 'Hey, I've got it on 72 and my house is 78,'" said Hinchman.

Hunchman recommends changing air filters every 30 days in an A/C system, and getting older systems a tune up.

"That (tune up) goes through and cleans everything throughout to make sure it's at its peak efficiency," said Hinchman.

He also said getting a maintenance report on an A/C system will help determine what needs to be fixed, or if the system should be replaced.

"If it is getting older, a lot of times it would actually be less money to replace it out of pocket than to keep putting all this money into it," said Hinchman.

Energy Star offers advice on selecting an approved HVAC contractor on its website, and also has more tips on heating and cooling your home efficiently.