Check these before you call for HVAC service
Before you book a service call, spend five minutes on three checks — the thermostat, the power and breaker, and airflow. A surprising share of "no heat" and "no cool" calls turn out to be a dead thermostat battery, a tripped breaker, or a clogged filter, all of which you can fix for free. If the checks don't solve it, they still make the visit faster — and there are a few situations where you should skip them and call right away.
What should you check before calling?
Three areas cover almost all of the self-fixable problems. At the thermostat, make sure it's set to HEAT or COOL rather than OFF, that the target temperature is a few degrees past the room, and that the batteries are fresh. For power, confirm the switch on the furnace or air handler is ON, the breaker hasn't tripped, and the furnace door is fully closed — it has a safety switch that keeps the system off when it's open. For airflow, swap a dirty filter, open the supply and return vents, and clear leaves or snow off the outdoor unit.
Symptom-by-symptom walkthroughs: AC troubleshooting and furnace troubleshooting. The filter itself: air filters.
What should you have ready when you call?
If the problem survives the checklist, a couple of minutes gathering details makes the call — and the visit — go smoothly. Note the system's brand and rough age and whether it's gas, electric, or a heat pump (it's on the label on the unit), plus any error code blinking on the control board. Then describe the problem: the exact symptom (won't start, no heat, a specific noise, a leak), when it started, and which checks you already ran. A technician who arrives knowing all that isn't starting from scratch.
What happens at the visit: what to expect from a service call, and the fee on HVAC service call cost.
When should you skip the checks and call right away?
Most problems are safe to work through the checklist first — a system that won't start, a room that's too hot or cold, weak airflow. But some situations are not DIY moments, and the right move is to get to safety and call immediately: a gas or rotten-egg smell (leave the house and call from outside), a burning or electrical smell or smoke, a carbon-monoxide alarm sounding, or no heat during a hard freeze or water pouring from the unit. When in doubt on anything involving gas, fire, or CO, don't troubleshoot — call.
Why these checks save you money
The reason to run the list is simple: a service call has a fee, and it's frustrating to pay it only for a technician to flip your thermostat to HEAT or slide in a fresh filter. Doing the five-minute checks first means you fix the free stuff yourself and only pay for a visit when there's a genuine repair to make. And when there is, the notes you gathered help the technician get to the real problem faster. We're a neutral routing service, not the company sending the truck — so this list is here to save you a call, not sell you one.
One call routes you to a licensed local contractor in your area: (888) 810-2291.
Common questions
What should I check before calling an HVAC company?
Run three quick checks first: the thermostat (right mode, set past the room temperature, fresh batteries), the power (furnace switch on, breaker not tripped, panel door closed), and airflow (clean filter, open vents, clear outdoor unit). These fix a real share of no-heat and no-cool calls for free.
Why won't my AC or furnace turn on — is it something simple?
Often, yes. The most common free fixes are a thermostat set to OFF or with dead batteries, a tripped breaker, a furnace door not fully closed (it has a safety switch), and a filter so clogged it shut the system down. Check those before assuming the worst.
What information should I have ready when I call?
Have the system's brand and rough age, whether it's gas, electric, or a heat pump, any error code blinking on the control board, the exact symptom and when it started, and which checks you already tried. Two minutes of notes makes the visit faster and the quote more accurate.
When should I skip the checks and just call?
Skip them and act immediately for anything dangerous: a gas or rotten-egg smell (leave and call from outside), a burning or electrical smell or smoke, a carbon-monoxide alarm, or no heat during a hard freeze. Those aren't DIY moments — get to safety first.
Will checking these things void my warranty?
No — changing a filter, resetting a breaker, and checking the thermostat are normal homeowner tasks. What can affect a warranty is opening sealed components or doing gas or refrigerant work yourself, which is exactly the line where you should call a licensed technician instead.
Do these checks really save money?
They can. If a technician drives out only to flip your thermostat to HEAT or replace a $15 filter, you've paid a service-call fee for something you could have fixed. Running the list first means you only pay for a visit when there's a real repair to make.
How do I reset my HVAC system?
For a tripped breaker, switch it fully OFF and then back ON. For the unit itself, turning the thermostat off, waiting a minute, and turning it back on clears many minor faults; a furnace also restarts when you open and firmly re-close its door. If it trips again right away, stop and call — that's a fault, not a fluke.