Back Button

HVAC Stops Cooling After Lightning

Steven Symes

If your house’s air conditioner is running during a lightning storm, your house or air conditioner does not need to suffer a direct lightning strike to be damaged during the storm. Nearby lightning strikes may spike the power supply in your house, potentially tripping the air conditioner or damaging the unit.

Thermostat Problems

A nearby lightning strike may damage several parts on the air conditioner.

Your air conditioning unit is controlled by a thermostat inside your house. If the thermostat is affected by the lightning storm, the air conditioning will not function properly or even turn on until you restore the thermostat to its properly working condition. If you have an electronic thermostat inside your house, check that the display is still working, indicating the thermostat is receiving power. If the thermostat is blank, check your house’s electrical panel to see if the breaker switch for the thermostat is flipped. After checking and flipping the breaker switch, if the thermostat still does not work, remove the old batteries and install replacements.

Air Conditioning Breakers

Your air conditioner might not work because the spike in electricity may have tripped one of its breakers. The tripped breakers help protect the air conditioner from damage, just as breakers protect the rest of your house’s electrical system. The breakers for your air conditioner are likely located near the air conditioning unit outside your house. If you are not sure where the breakers sit, follow the electrical wires coming out of the air conditioner until they run into a small box and then open the box. Flipping the switches back to the “On” position restores the electrical flow to the air conditioner.

Electrical Surge Damage

A nearby lightning strike can cause a surge of electricity to flow into your house’s electrical wiring. The sudden spike in electricity can ruin any electrical device on the grid that is not guarded by a surge protector, including your air conditioner. The damage from the lightning strike may result in melted wiring, a blown air compressor or blown electrical fuses for the air conditioner. The only way to tell which parts have been damaged by the electrical surge is to have a technician come to your house and place the air conditioner under a series of tests.

Long-term Damage

Even though you restore your air conditioner to its working order and it starts running and cooling your house again, your air conditioner may still have damage from the lightning strike. If you do not have an air conditioner technician test your unit, certain parts inside the air conditioner may work but not as efficiently as before. These damaged parts place an undue load on the air conditioner, causing other parts to begin failing as well. This means your air conditioner may work for a period of time after the lightning strike and then need further repairs from the lightning’s damage.