A central air conditioner has two parts: an internal air handler and the external condensing or condenser unit. The health of both parts is vital to the cooling process but the condensing unit usually requires the most maintenance attention. Failing to maintain the condensing unit can lead to a loss of cooling efficiency, which means you need to thermostat even lower to reach a comfortable temperature. The lower setting can lead to a spike in your electricity bill.
Here are two common condensing unit issues that can spike your electric bill. Some fixes you can perform yourself while others should be left to a reputable HVAC repair technician.
Dirt or Debris Buildup
The condensing unit is located outside and needs a few feet of clearance on each side for proper ventilation. The outer casing has fin-like notches to allow said ventilation. This setup makes it easy for dirt and debris to collect in various parts of the unit and threaten the efficiency.
One of the first places to check is the casing itself. Pull any leaves or branches out of the fins and lightly dust off the exterior using the end of a dry mop or broom. You can then open the case to check for more debris. Consult your owner's manual if you're unsure how the case opens. Make sure you cut all power to the unit before opening.
Check the interior side of the fins for any dirt or debris. You should see some coils lining the inside wall. These are called condenser coils. You can multitask and remove dirt from the interior fins and the coils at the same time. Affix a spray nozzle to a hose and hold the hose, with the water off, inside the condensing unit. Position the hose so that the sprayer is near the coils aiming out towards you. Turn the water onto a low spray and move the spray slowly over all of the coils and the interior fins.
Refrigerant is essentially the gas that powers the cooling system and problems with that gas can make the system less efficient or shutdown entirely. Common refrigerant problems include low levels, overfilling, and refrigerant in need of recharging.
HVAC repair technicians are the only people able to purchase refrigerant in most locations as its a strong chemical. The tech would also need to perform the recharging procedure. So it's important to call in professional assistance if you suspect a refrigerant issue.
Make sure you call a reputable company as an inexperienced technician can overfill or use the wrong refrigerant. Both of those actions can worsen your cooling problems and potentially destroy your entire cooling system.