Answer-First Guidance
Common HVAC problems in Los Angeles
The same honest answers the troubleshooter gives, written out — what each symptom usually
means, what's safe to check yourself, and when it's genuinely a technician job.
From the family that's serviced LA homes for 52 years.
Why is my AC not cooling the house?
The most common causes are a clogged air filter, a thermostat set wrong (or with dead batteries), a tripped breaker, or a blocked or iced-over outdoor unit. Check those four first — they're safe to do yourself and fix a meaningful share of “no cooling” calls. If the system still won't cool, the fault is usually a failed capacitor, contactor, or low refrigerant, and those are strictly technician repairs: refrigerant handling is EPA-regulated and high-voltage parts are dangerous. In Los Angeles heat, treat a cooling outage as a priority and call a licensed HVAC contractor.
Why is my heat pump blowing cold air in winter?
Often it isn't broken — heat pumps periodically run a defrost cycle on cold mornings, and for 10–15 minutes the outdoor unit may steam or pause while indoor air feels cool. Steady cold air beyond that usually points to a reversing-valve fault, low refrigerant, or a control problem, all of which need a technician. Before calling, confirm the thermostat is set to HEAT (not COOL or EMERGENCY HEAT) and the filter is clean.
Why is there water around my indoor unit?
Water at the indoor unit almost always means the condensate drain line is clogged, the drain pan has rusted through, or a frozen evaporator coil is thawing. Turn the system off at the thermostat to stop new condensate from forming and move anything water-sensitive away. Don't keep running it — water damage to drywall and flooring compounds quickly, and an iced coil that keeps running can damage the compressor. The drain, pan, or icing cause needs a technician.
Why is airflow weak, or why are some rooms hotter than others?
Start with the two things you can fix yourself: replace a dirty filter and make sure supply registers are open and not blocked by furniture (closing vents to “push” air to other rooms actually raises duct pressure and makes it worse). If that doesn't help, the usual culprits are leaky or crushed ducts — very common in hot LA attics — a weakening blower motor, or a system that was never balanced for the floor plan. A duct assessment finds where the air is going; for one stubborn room, a ductless mini-split zone is often the most honest fix.
What does a burning smell from my vents mean?
Turn the system off at the thermostat immediately — and at the breaker if you can reach it safely. A brief dusty smell the first time the heat runs each season is normal, but a persistent burning, hot-plastic, or electrical smell means overheating wiring, a failing motor, or a control fault, and those are fire risks. Do not run the system again until a licensed technician has traced the source.
What should I do if I smell gas near my furnace?
Leave the house first. Don't flip light switches, light flames, or start the HVAC system on your way out. From outside, call your gas utility's emergency line — in the Los Angeles area that's SoCalGas at 1-800-427-2200 — and they will make the home safe at no charge. Only after that should you have an HVAC contractor inspect the furnace and gas connections; a furnace that produced a gas smell shouldn't run again until it has been checked.
Why does my AC turn on and off constantly (short-cycling)?
Short-cycling — starting and stopping every few minutes — is most often caused by a clogged filter, a refrigerant leak, a failing sensor, an oversized system, or a thermostat mounted where a draft or sunbeam fools it. Replace the filter and make sure registers are open; if the cycling continues, book a diagnostic promptly. Every short cycle hard-starts the compressor, the most expensive component in the system, so this problem gets pricier the longer it runs.
Why did my energy bill suddenly spike?
If your usage habits haven't changed, the usual suspects are a clogged filter forcing longer run times, duct leaks dumping conditioned air into the attic, refrigerant loss, or an aging system quietly losing efficiency. Replace the filter first. If the next bill is still high, an efficiency assessment can measure where the energy is actually going — duct sealing and modern inverter heat pumps are the two fixes that most often pay for themselves in Los Angeles homes.
