HVAC Maintenance Checklist for Los Angeles Homeowners
An air conditioner in Los Angeles works a longer year than the people who designed it planned for. The cooling season opens in April and often runs past October, the condenser sits in full sun, and the ducts run through an attic that passes 130 degrees on a hot afternoon.
Maintenance here is mostly about getting ahead of two local problems, runtime and dust. A national once a year schedule was written for a four month cooling season. What follows is what needs doing here, season by season, and which parts are worth paying someone else to handle.
Spring, before the first warm week
Spring is the only time of year when you get to choose your appointment slot. By the first ninety degree week in June, every contractor in the county is booked.
Book the cooling tune up now. A proper visit is not a visual inspection: the technician should clean the condenser and evaporator coils, check refrigerant charge against superheat and subcooling instead of topping it off by feel, measure the temperature split between return and supply air, test capacitor and contactor condition, check amp draw against the data plate, and confirm the thermostat is calling correctly. Ask for those readings in writing.
Clear the outdoor unit. Two feet of open space on every side, and cut back whatever has grown in over winter. The shrubs people plant to hide a condenser are strangling the airflow it runs on.
Rinse the condenser fins gently from the inside out with a garden hose, never a pressure washer. Bent fins do not recover.
Pour a cup of water down the condensate drain to confirm it runs. A blocked drain in July backs up into the pan and, in most attic installations, into the ceiling below it.
Look at the ducts if you can reach them safely. Visible disconnections and crushed flex are common in older attics, and the Department of Energy puts typical duct loss at 20 to 30 percent of the air moving through a system. If one room has never been comfortable, this is usually why, and a duct inspection will tell you more than another thermostat adjustment.
Summer, the months that do the damage
Check the filter monthly from June through September. Valley dust and Santa Ana grit load a filter far faster than the label assumes.
Watch the bill, not the thermostat. A jump with no change in how you are living usually means refrigerant is low, a coil is dirty, or a component is starting to fail. Catching it in July is a repair. Ignoring it until August is often a compressor.
Close blinds on the south and west sides between roughly ten in the morning and four in the afternoon. It sounds trivial and it measurably reduces how long the system runs.
Leave the thermostat alone once it is set. Dropping it to 65 does not cool the house faster. It runs the same system at the same rate for longer.
Listen. Grinding, squealing, a hard clunk on startup, or a unit that starts and stops every few minutes are all early warnings. Short cycling in particular is worth a service call instead of a wait and see.
Fall, the short window before heating season
Los Angeles heating season is brief enough that most people skip this entirely, then discover a dead furnace on the first cold night in December.
Have the furnace or heat pump checked before you need it. On a gas furnace that includes the heat exchanger, the burners and the ignition system. A cracked heat exchanger is the one HVAC fault that is genuinely dangerous, and it is not visible without dismantling the unit.
Test the carbon monoxide detectors. California requires them in homes with gas appliances, and they have a service life: most units expire seven to ten years after manufacture, and the date is printed on the back.
Vacuum the supply and return vents. A summer of dust sits in them, and the first heating cycle sends it through the house.
Run the heat for fifteen minutes on a mild day. The burning smell on first use is normal dust. Anything else is worth a look before winter.
Winter in Los Angeles
Keep changing the filter monthly if the heat is running daily.
Hold the thermostat at 55 degrees or above when you travel. Hard freezes are rare here and not impossible, and the cost of being wrong is a burst pipe.
Call on short cycling. A furnace that lights, runs briefly, and shuts off before reaching temperature is usually overheating, and the common causes are a clogged filter or a failing flame sensor. Both are cheap. What they lead to is not.
The one job that matters every month
If you do nothing else on this page, change the filter.
Every one to two months through the cooling season, monthly if you have pets, live near a freeway, or anyone in the house has allergies. The Department of Energy estimates that replacing a clogged filter with a clean one can cut an air conditioner’s energy use by 5 to 15 percent. No other maintenance task returns that much for that little.
One caution on filter choice. A very high MERV rating restricts airflow, and on a system that was not designed for it that restriction causes the coil to freeze and the blower to strain. MERV 8 to 11 suits most residential systems. If you want tighter filtration than that, have someone measure the static pressure first.
What is worth paying someone to do
Filters, clearance around the condenser, a gentle coil rinse and the condensate drain are all homeowner jobs. Everything below needs a technician with instruments:
Refrigerant charge, which has to be verified against superheat and subcooling, not pressure alone.
Electrical testing, including capacitor capacitance and contactor condition.
Static pressure and airflow measurement across the air handler.
Duct leakage testing, which California’s Title 24 code requires independent HERS verification of after most duct work.
Anything involving the heat exchanger or the gas train.
An annual maintenance visit covers most of this in one appointment. Two visits a year is reasonable for a system that heats and cools.
What you should not do yourself
Refrigerant is the clear line. Handling it requires EPA Section 608 certification, and buying a can of sealant off a shelf does not make the leak go away. It contaminates the system and turns a repair into a replacement.
Leave the electrical alone as well. Capacitors hold a charge after the power is off, and a run capacitor can injure someone who assumes otherwise.
If a system is down entirely in a heat wave, the safe order is to check the breaker, check the filter, check that the thermostat has power, then call.
Common questions
How often should I service my HVAC system in Los Angeles?
Once a year for cooling, before the season starts, and once for heating if you have a furnace or heat pump. The long Los Angeles cooling season puts more runtime on equipment than the national once a year guidance assumes.
How often should I change my air filter in Los Angeles?
Every one to two months during the cooling season, and monthly with pets, allergies, or a home near a freeway. Local dust loads filters faster than the manufacturer’s ninety day estimate suggests.
Is an HVAC maintenance plan worth it?
It is worth it if it includes the measurements and not only a visit. A plan that covers the seasonal tune up, priority scheduling during heat waves, and a discount on repairs usually pays for itself the first time you need service in August.
Does a smart thermostat actually save money?
ENERGY STAR puts the average saving from a certified smart thermostat at about 8 percent of heating and cooling costs. The gain comes from adjusting while nobody is home, so it is larger in a house that is empty during the day.
Book the tune up before the first heat wave
Most of the emergency calls we run in August were avoidable in April. If you want the background on why equipment here ages faster than the warranty suggests, this explains what the heat is actually doing.
Cool Breeze LA services systems across Los Angeles, Calabasas, Sherman Oaks, Glendale, Pasadena and Burbank. Call (626) 548-3087 or schedule online.