Your central air conditioner and refrigerator are pretty much cousins. Both appliances work the same way: they suck air in and cool it down by moving the heat from the sucked air to the refrigerant. This substance, colloquially known as “Freon”, doesn’t technically run out per se, but there are signs that indicate the need for a refill or, as air conditioning technicians in Edmonton call it, a “recharge”.
Central air conditioning systems use refrigerant that can technically last a lifetime, but certain circumstances can cause issues with the coolant supply. Accidental damage, natural wear and tear, and contaminants are some of the most common reasons. One of the first things you should check for signs is the thermostat—sometimes, units simply need to be reset electronically and may not actually need a recharge at all.
After trying the thermostat tip, determine if your home cooled down as expected. If not, you should move on and check for ice buildup in your unit. Central air conditioners have an exterior unit, with visible copper lines that contain refrigerant. If coolant levels are low, the air conditioner’s evaporator coil tends to get too cold, which causes cool refrigerant to flow back the coolant line. This is what causes the ice buildup.
No ice buildup on the pipes? If so, try going over your most recent electric bill again, and check if it’s unusually higher than the one from the month prior. An air conditioner that’s low on refrigerant has to work much harder to cool down your home, causing the unit to consume more energy. While this may not be a direct indicator of an urgent Freon recharge, keeping a sharp eye on your bills helps you spot such problems before they get worse.
Checking the vents out can also help. If all vents are blowing out either warm or room-temperature air, it’s one of the surest signs that coolant levels are low. Simply hold your hand in the front of vents and feel the air blowing out, though you do have to give the machine a bit of leeway. Fifteen minutes is enough since the warmer air might only be residual. If your unit still blows out warm air after the fifteen warm-up, you may need to have your coolant levels recharged.
If you have reason to suspect your central air conditioner requires a refrigerant recharge, do not hesitate to contact an HVAC service, such as Capital Plumbing and Heating, to come and take a look at your unit. Experienced air conditioning technicians can easily replenish coolant back to optimum level, as well as make any necessary repairs to ensure your central air conditioning system runs perfectly.
How Can I Tell If My Central Air Needs Freon? eHow.com