Spring AC cleaning

What you need to know

If home components had personalities, AC systems would be the chill sibling who is down to rough it and go camping yet also is focused on skincare and gets regular laser treatments. AC systems, whether central air or mini-splits, battle water and dust continuously and their outdoor components get pummeled by the elements. They can last 15+ years (up to 20 for central), but lack of upkeep can make them less efficient and shave years off their lives.

There are a few different standard maintenance packages you can choose from to protect your ACs from going bust during the summer heat and keep your air clean:

• inspection of all indoor and outdoor components

• + indoor vent, or duct, cleaning/brushing (basic cleaning)

• + coils, fans, and condenser cleaning/washing (deep cleaning)

Annual inspections along with cleanings every 2-3 years should be sufficient to maintain the life of your system, though air quality advocates and vent cleaning providers (duh) also recommend annual basic cleanings to keep your AC most efficient and prevent mold. Over the past 6 years, we have done annual inspections and one deep clean (costs detailed here), though moving forward we will add basic vent cleanings every two years given they should prolong the need to deep clean and give me peace of mind that our ACs aren’t circulating dirty air around. Many HVAC providers will suggest some tune-ups after an inspection, but if your system is mold-free and less than a decade old it should be relatively low maintenance so scrutinize these if the list is long.

Spring has sprung!

The Anatomy of an AC system

At their core, ACs collect heat in your home and dump it outside. A chemical compound called refrigerant travels through your AC components transitioning from liquid to gas as it absorbs heat indoors before transitioning back to liquid once it releases the heat outside.

Buckle up and join me on a ride through an AC system: Starting with an AC system’s indoor unit, a blower fan pushes hot air from the home across an evaporator coil filled with cool refrigerant. Filters catch dust before it reaches coils, as dust can act as insulation and jeopardize heat transfer. The coil absorbs the heat, and the blower fan pushes cool air back through ducts, or vents. As warm air hits the cool evaporator coil it creates condensation, which drains through a condensate drain pan that connects to a drain line. The hot refrigerant travels through copper pipes to an outdoor unit, the condenser, which dumps hot air outside and then has an engine, or the compressor, that pressurizes the refrigerant to travel through the loop again. Mini-split systems are similar, though instead of refrigerant flowing through ducts throughout a home, this cycle is limited to each room.

What happens during inspections

Annoyingly, thorough HVAC inspections and vent cleanings typically require two different providers. For HVAC inspections, technicians 1) make sure components are working correctly and 2) check for water and dust, which lead to mold and pollution and can weaken heat transfer.

HVAC inspections include:

• Inspect outdoor units, which particularly get rocked by the elements. Out of all AC components, the compressor is typically the most expensive to fix.

• Check refrigerant levels, which should remain constant in this closed loop. If refrigerant is low, you most likely have a leak somewhere in your system, or more rarely it was improperly installed. As systems get older, small leaks become more common. If a technician quotes you for a few pounds of refrigerant refill, something is wrong that warrants repair. I’ve been quoted anywhere from $90-$200/lb of refrigerant refills.

• Check for dust and water, which can build in vents, coils, or drain pans, especially if the drain pan isn’t angled and functioning correctly.

• Request that a technician also check duct cord coating around the condenser. Alternatively, this is a simple check that you can do yourself. We learned about the importance of this coating the expensive way.

• For central units located in the ceiling, ask technicians to check whether you have a dedicated return duct (also called a closed plenum). Many times (one provider cited 8/10), central units don’t have it and instead draw air to circulate from the crawlspace. If this is the case, technicians can install a proper duct and filter grill.

Vent/duct cleanings include:

• Basic cleanings include removing dust from indoor filters and vents.

• Deeper cleanings include cleaning the fan, coil, and condenser units. Typically technicians use brushes and vacuums, though if there are signs of mold they may use sanitizers.

I checked with a few different local service providers, from premium HVAC and vent cleaners to lean shops, and off-the-shelf pricing for one unit averages around:

• Central AC (1 thermostat and ~5 vents) - $350 (basic) - $1,200 (deep)

• Mini-splits - $150 (basic) - $250 (deep)

If your sole goal is elongating the life of your system and preventing expensive maintenance, you can get by with an annual inspection and basic cleanings 2-3 years, though if you have allergies, young kids, or are mold or air-quality conscious you may want to do a basic cleaning more often. You can find recommended BK providers here.

Cleaning our AC ducts to circulate clean air to our family makes me feel marginally better for washing their clothes in a mold-riddled machine. Teaser for next time!