This doesn't mean running out and buying the latest swim wear. It means checking your home's heat and air-conditioning system.
First, change your filters in your heating/cooling system. Change them regularly - at least monthly.
Next change your thermostat over to "cool" and test the system by turning the temperature down. If the air conditioner does not turn on, first check to make sure no breakers are tripped. If you can't figure out the problem, call your heating and air conditioning repair person. Calling early may keep you from making an "emergency" call when the temperatures are soaring and the repair people are too busy.
If your cooling system turns on, make sure it is putting out adequate cooling. If it's not, and you can't figure out the problem, call your heating and air conditioning repair person. Make sure you set it at 78 degrees.
If your air conditioner needs replacement do it BEFORE the HOT WEATHER HITS because heating & air conditioning repair people will be very busy. And more than likely, some other things around your home need attention as well. Your air ducts may need testing for leaks and then sealed. Your attic insulation probably has compacted, so you need to add an additional 5 to 8 inches. Your windows and doors and other parts of the building envelope may need caulking and weather stripping. You need solar window film to keep out the heat.
Consider changing your old thermostat to a programmable one. You can save up to $100 a year by using a new set-back thermostat. If your thermostat is really old and uses a mercury switch (a glass tube filed with silvery substance) call your local public works department to find out how to dispose of this toxic material.
Consider installing a whole-house fan that uses cool air in the evening to cool the entire house and push hot air out of the attic area.
If you cover your air conditioner's condenser unit (the part that is outside the house) for the winter, take off the cover and hose down the coils. Clear areas around the condenser unit so that it has full air flow. Install ceiling fans or whole house fans to help reduce your need to use the air conditioner.
Take down the old storm windows, if you live in areas where you need them, and put up screens in their place.
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