Before You Call for HVAC Repair
Many no-heat and no-cool calls end at a setting, a breaker or a filter. Check those first, and know when it is time for a technician. Something else? Check any home repair.
Question 1
What is going on?
General guidance, not an inspection. When something feels unsafe, stop and call a professional.
Every answer at a glance
Act now
Treat it as carbon monoxide until proven otherwise
Carbon monoxide has no smell and can kill.
Act now
Leave the house and report the gas smell
Do not try to find the leak.
You can likely fix this yourself
Start with the settings and the power
Many no-heat and no-cool calls end at a thermostat setting or a tripped breaker.
You can likely fix this yourself
Clear the airflow first
A clogged filter or dirty outdoor coil can make a system shut down or lose capacity.
HVAC filter cheat sheetCall an HVAC technician
The furnace needs a technician
Past the thermostat, filter and power, the work involves burners, gas valves and control boards. Note any blinking code on the furnace and pass it on. In freezing weather, say so when you book, and protect your pipes.
Call an HVAC technician
Likely a capacitor, contactor or compressor
Turn the system off so it does not burn out the compressor. The parts in the outdoor unit hold a dangerous charge even with the power off, so leave this to an HVAC tech.
DIY if you are comfortable, otherwise call
Thaw it, then check airflow
Ice comes from too little airflow or low refrigerant. Airflow you can fix. Refrigerant needs a licensed tech.
HVAC filter cheat sheetDIY if you are comfortable, otherwise call
The condensate drain is likely clogged
Algae can block the small drain line, and many systems shut off when it backs up.
DIY if you are comfortable, otherwise call
Check vents and accessible ducts
Blocked registers and disconnected ducts are common. Persistent hot or cold rooms may need duct balancing or sizing from a pro.
Ductwork sizing calculatorCall an HVAC technician
Shut it off and book a technician
Grinding and squealing usually point to a failing motor or bearing, and loud banging in a furnace can be delayed ignition. Running it can make the damage worse. Note when the noise starts and where it comes from.