A furnace tune-up is a once-a-year inspection and cleaning that tests the safety controls, cleans the parts that cause most no-heat failures, and checks that the furnace is burning gas safely.
A good one takes about an hour. The best time to do it in North Texas is October or November, before the first hard freeze puts every furnace in town to work on the same night.
Our September post covered the fall HVAC checklist you can do yourself. This one is about the part a technician does, so you know what you're paying for and can tell a real tune-up from a quick look.
What a real furnace tune-up covers
Here is what our heating techs work through on a gas furnace.
Safety checks
Inspect the heat exchanger for cracks or rust. A cracked heat exchanger can let combustion gases into your home's air.
Test for carbon monoxide at the flue and around the unit.
Check the venting and flue pipe for gaps, blockages or bad slope.
Test the high limit switch, rollout switches and pressure switch so they actually shut the furnace down when they should.
Check the gas line and valve for leaks.
Burner and ignition
Clean the flame sensor. A dirty one is a common reason a furnace lights and then shuts itself off.
Inspect the hot surface igniter for cracks and test its resistance.
Check burner flame color and pattern. A steady blue flame is what you want.
Measure gas pressure against the manufacturer's spec.
Airflow and electrical
Check or replace the air filter.
Inspect and clean the blower wheel and check the motor's amp draw.
Test the capacitor, if your blower uses one.
Tighten electrical connections and look for heat damage on wires.
Measure temperature rise across the furnace to confirm it's heating within its rated range.
High-efficiency furnaces
If your furnace has white PVC vent pipes, it also gets the condensate drain, trap and pump cleared and tested. A clogged drain can shut the furnace down or leak into the ceiling below an attic unit.
Thermostat
Confirm the thermostat is calling for heat correctly and the setpoint matches the room.
Run the system through a full heating cycle start to finish.
When it's done, you should know what was checked, what was cleaned, and anything that's wearing out.
Why it matters more in North Texas than you'd think
A Dallas-Frisco furnace has an odd life. It sits idle for most of the year, then gets pushed hard for a handful of cold weeks, sometimes with almost no warning. Parts that dried out, corroded or collected dust over the summer get tested all at once on the first cold night.
That first cold night is the worst time to find out your igniter is cracked, because every furnace company in DFW is busy at once. A tune-up in the fall catches the cheap problems (a dirty flame sensor, a weak capacitor, a clogged filter) before they leave you without heat. It also gives you time to plan if the furnace is near the end of its life, instead of making a replacement decision in a cold house.
There's also the safety side. A gas furnace that hasn't been checked in years can have a cracked heat exchanger or a blocked flue and still seem to run fine. Have working carbon monoxide detectors on every floor whether or not you get a tune-up.
How to tell if a tune-up was rushed
Not every tune-up is the same. A few signs the visit wasn't thorough.
The tech was in and out in 15 minutes.
The burners were never fired and watched through a full cycle.
Nobody looked at the heat exchanger or tested for CO.
You got a sales pitch for a new system but no written list of what was checked.
Ask for the checklist. If a part is wearing out, ask to see it. We'd rather show you a worn igniter than ask you to take our word for it.
Do you need one every year?
For a gas furnace, yes, once a year. Most manufacturers require regular professional maintenance to keep the warranty valid, so check your paperwork. If you also have central AC, a spring AC check and a fall furnace check keep both sides of the system covered. An easy way to remember: book the furnace visit when you set the clocks back.
Book your tune-up before the first freeze
The easiest furnace repair is the one you don't need in January. Get on the schedule now, while there's still room on the calendar and the furnace isn't running every night.
Schedule a furnace tune-up or call (469) 285-4457. We're family-owned and based in Frisco, and we'll tell you straight what we found.
Already have a problem? Start with our guide to a furnace that won't turn on.
Frequently asked questions
What is included in a furnace tune-up?
A full tune-up includes safety checks (heat exchanger, carbon monoxide, venting, limit switches), cleaning the flame sensor and blower, testing the igniter and capacitor, checking gas pressure and burner flame, replacing or checking the filter, and running a full heating cycle.
How long does a furnace tune-up take?
Usually about an hour for a standard gas furnace. High-efficiency furnaces with a condensate drain can take a bit longer. Fifteen minutes is too short to do the safety checks properly.
When is the best time to get a furnace tune-up in Texas?
October through early November, before the first hard freeze. That gives time to fix anything the tech finds before you need the heat.
Is a furnace tune-up worth it?
For most homes, yes. It catches inexpensive problems before they become no-heat emergencies, checks for safety issues like a cracked heat exchanger, and is often required to keep the manufacturer's warranty valid.
Does a heat pump need a tune-up too?
Yes. A heat pump runs in both summer and winter, so it gets more hours than a gas furnace. It's worth having it checked twice a year, once before cooling season and once before heating season.