Now that the weather is getting warmer, the countdown is on to making that fateful decision: When do I turn on my air conditioner?
This is also the start of the annual ritual of clients, friends and strangers calling us with the question of why their air conditioner isn’t working when they turn it on for the first time. It is the same routine EVERY year!!!
Caller: “We are BOILING and we turned the switch on the AC and nothing happened. What is wrong with this stupid machine?”
Holistic Home Energy Services: “Ok, no problem. We will figure this out. When was the last time you changed your air filter?
Caller: (pause) “Uhmmmm, I don’t remember.”
Holistic Home Energy Services: “Ok, why don’t you head down to your indoor unit and pull the filter out.”
Caller: (pause for walking) “Oh my gosh!!! It is disgusting!!”
Like so many other things in life, the cleaner something is, the better it will work. An air conditioner’s filter is no different. The dirtier the filter, the less air it allows back through to your unit. When an insufficient amount of air crosses the COLD evaporator a/c coil on your indoor unit, it freezes up and eventually becomes a block of ice.
Typically, a dirty air filter is the final straw to making an AC unit shut down. As we have written about before, one of the biggest problems we have with residential HVAC systems is improperly sized duct work. In almost every home we work in, the duct work is undersized, which does not allow the proper amount of air movement. When a filter gets dirty, it takes a system that is already starved for air and puts even more strain on it, ultimately freezing the evaporator coil and locking up the system (or even worse, breaking your compressor, which is the heart of your air conditioning system).
Once we have diagnosed the problem (a dirty air filter), the inevitable follow-up question is, “what should I buy to replace it?”
This is an important inquiry, and we are about to reveal a dirty secret within the HVAC Industry: No matter how attractive and persuasive the marketing display is, do NOT buy High Efficiency Pleated Air Filters that you can find at your typical Home Center stores. In fact, it is our recommendation that you buy the cheapest air filters you can find at a Home Depot or Lowes. They allow the most amount of air flow with the least amount of resistance, while still keeping large dirt & dust particles from reaching the inside of your equipment. Throw-away air filters are equipment filters and are not meant to clean the indoor air of your house. They are simply meant to protect the indoor furnace or air handler from getting dirty. The only way to truly address IAQ (Indoor Air Quality) is to install a bypass HEPA Filter, UV Sterilization System or Electronic Air Cleaner (which we will cover on an upcoming post).
So, in the meantime, enjoy the early start to spring and stay cool with a properly working AC unit.
energyMusings is written by Sean Schmidt, President of Holistic Home Energy Services, an Energy Auditing & Home Performance Contractor in Maryland. In addition to being a certified Building Analyst and Envelope Specialist, Sean has been in the HVACR field for 20 years. He is currently the President of Heating & Air Conditioning Contractors of Maryland, sits on the Board of the Maryland Alliance for Fair Competition (MAFC) and is an active member of Efficiency First.