Why We Do Not Check Air Conditioners in the Winter

Inspecting and servicing your air conditioning and heating equipment twice a year, in the spring and fall, is a best practice especially in the Houston and surrounding area. Routine HVAC maintenance can save you a surprise breakdown when it’s the least convenient. And we all know that is usually at night, with company in town, or our personal favorite, over a holiday weekend. Believe it or not, air conditioners should not be inspected too early in the season when it is cold because it could harm your HVAC system and cause unnecessary repairs.

How Cold is Too Cold?

If the temperature is less than about 65 degrees Fahrenheit, it is not a good idea to operate an air conditioner. The reason is tied to how your air conditioner works. In a nutshell, when it’s too cold, setting your system to run even colder to “test” it can cause refrigerant to back up where it shouldn’t be, potentially damaging equipment. This is never an issue when an air conditioner is running during warm weather.

How Basic Refrigeration Works

Vapor-compression refrigeration works the same way no matter what type of refrigerant is used. Your air conditioner removes heat or more accurately it “transfers heat” from the indoors to the outside, keeping you cooler inside. The refrigeration system is like a train on a circular track with refrigerant cycling back and forth. Refrigerant is how we harness the heat in the house and cycle it outside to be disbursed into the air. When there is a pressure change from the metering device, it will initiate an endothermic reaction causing the refrigerant to “grab” the heat as it vaporizes. Then the refrigerant vapor is pumped directly to the outdoor compressor which compresses the vapor. The hot gas circulates through the coil from top to bottom, and the fan pulls air across the coil thereby removing the heat. When enough heat is removed, an exothermic reaction takes place and the refrigerant returns to a liquid state. The cycle repeats over and over, cooling the indoors.

Main Components of Your Air Conditioner

Outdoor Unit (Condenser) – Your outdoor unit has three basic parts – a compressor, condenser coils and fan. Its overall job is to disburse heat gathered from the indoors. The compressor is a vapor pump which circulates the refrigerant. Lastly, the condensing coils are the mechanism the refrigerant has to transfer its heat to the outside air by way of the fan. This is why when you’re next to your outdoor condenser, a fan is blowing hot air outside all summer long.

The Indoor Unit can consist of a stand-alone evaporator coil or air handler, which has an evaporator coil. Every system has a metering device that calls for the right amount of refrigerant. The indoor coil exposes the refrigerant to the indoor air by way of an indoor fan, powered by the blower motor. The refrigerant becomes a vapor and absorbs the heat indoors much the same way that water absorbs heat and evaporates into steam. This refrigerant vapor is then funneled back outside to the outdoor unit. After the refrigerant releases its payload outside, it condenses back into a liquid to start the process all over again.

What is Flooding?

If you run your air conditioner when the weather is cold, you could “flood” the unit. This means that there is not enough heat to vaporize all of the refrigerant, so the resulting liquid form of the refrigerant can migrate back to the compressor. The compressor circulates vaporized refrigerant as it removes heat from inside to outside. The compressor can’t do its job if there is no heat for the refrigerant to gather. If there’s no heat for the refrigerant to gather, then the refrigerant doesn’t completely vaporize the way it normally would on a warm day which means the denser liquid refrigerant can flow back into the compressor – flooding it. When the compressor is “flooded” with liquid (rather than the vapor it is designed to work with), it does not function well. That’s why the compressor can be damaged when running the air conditioner when it is too cold. The damage can be incremental or it can be catastrophic. Unfortunately, a compressor represents 80-90% of the cost of an air conditioning unit. This is why home inspectors and air conditioning technicians do not recommend running the air conditioner when it is too cold.

Need An Inspection or Service?

As your Carrier Factory Authorized Dealer, Rob and Kenny at Terry’s A/C and Heating can help you inspect or repair your air conditioner or heater at the right time, so that regular service and minor maintenance can be swiftly handled. Give us a call at 281-495-7830 if you would like a service call and you live in the Southwest Houston area including Katy, Rosenberg, Richmond, Sugar Land and Fulshear. We look forward to the opportunity to earn your business and being your indoor comfort concierge.