Furnace Tune Up: When is it Time to Call in a Pro?
Updated: Mar. 20, 2019It varies, here's why.
Well, the short, standard answer is once a year. But next time the HVAC tech is there, ask if that’s really necessary. It could be that you have a newer furnace, your home is very clean, you have no pets, or your furnace and A/C aren’t used all that much because you live in a temperate climate. You could possibly go two or three years between furnace tune ups. By the way, here are some DIY furnace maintenance tasks to keep your furnace in good shape.
What does a furnace tune up consist of?
- Cleaning components like the heat exchanger, combustion chamber, burners, jets, blower motor and fan, among other things.
- Checking and clearing the condensate lines. These lines drain not only water generated from gas combustion, they also drain condensation that collects on the A/C coil above the furnace.
- Doing a temperature differential test. That means measuring the temperature of the air going into and leaving the furnace.
- Performing a combustion analysis of the exhaust checking levels of O2, C/O and C/O2.
- Checking the ignitor and flame sensor for wear.
What should a furnace tune up cost?
You should expect to pay anywhere between $90 to $150 for the cost of a furnace tune up performed by a reputable HVAC company. Beware of $50 furnace service “specials.” They often lead to fishing expeditions where the technician finds often expensive and sometimes unnecessary repairs to perform or upgrades to add.
Get more bang for the buck
While the technician is there, ask for advice on which filter you should be using. Depending on your lifestyle, health issues, furnace style and a few other factors, it could be that you’re using a filter that is too fine for the furnace to operate efficiently or too porous and isn’t doing a good job of filtering the air to the furnace and your home.
Here’s some helpful tips on choosing the right furnace filter.
If you’re interested in getting a smart home thermostat, you could have the technician install it while they’re already at your house. That way, you won’t have to pay for a separate service call. Just be sure to mention that when you call for the tune up, so they have the thermostat with them when they show up.
Learn more about smart home thermostats to determine if one is right for you.
Change a Furnace Filter
Your furnace may be big, bulky, and perform one of the most essential tasks in your home, but that doesn't mean it needs to be intimidating. Many regular maintenance tasks can be done by homeowners and changing the furnace filter is a simple one that will save money and prolong the life of your furnace. Here's how. Plus: Simple Furnace Fixes You Can Do Yourself
Make Sure the Chimney Exhaust Flue is Clear
Drawn by the warmth, birds sometimes fall into the chimney exhaust flue. Turn the furnace off and the thermostat all the way down, then dismantle the duct where it exits the furnace and check for debris. Be sure to reassemble the sections in the same order and direction that you took them out. Here's how to tell if you need a new furnace.
Flush Out Drain Lines
High-efficiency furnaces can drain off several gallons of water a day in heating season. If the drain lines become restricted by sediment or mold growth, the furnace will shut down. If the drain hose looks dirty, remove the hose, fill it with a mixture of bleach and water (25 percent bleach), then flush it after several minutes.
Look For Blocked or Leaky Ducts That Can Restrict Airflow
If your furnace comes on but one or two rooms are cold, first make sure all the room registers are open. Then examine any ductwork you can get access to and look for gaps between sections or branching points. Seal any gaps between sections of duct with special metal duct tape. Don't use standard cloth duct tape—it quickly deteriorates, and it may also cause ducts to leak if it was used to seal sections in the past. Also check for handles protruding from the ductwork. These are dampers or air conditioner bypasses—make sure they're open. Learn more about working with round duct work here.
Clean Away Leaves and Debris From Heat Pumps or Intake and Exhaust Vents
If you have a furnace that vents out the side of the house, make sure nothing is blocking the intake or exhaust. If either of the pipes is covered with screen mesh (like window screen), replace it with 1/2-in.-mesh hardware cloth. If ice is clogging one of the pipes, you have a bigger problem somewhere in the system. Clear it off and call a technician to find out why it's happening. If you have a heat pump, clear away grass and leaves from the fins of the outdoor compressor unit. Before heating season starts, hose it down gently from the top to rinse dirt and debris out of the housing.
Inspect the Burner Flames
Turn the power switch on and activate the burners by turning up your thermostat. Inspect the burner flames. The flames should be fairly even and blue. Yellow flames indicate dirty burners. (Don’t breathe on the flames because the extra oxygen will also make them turn yellow.) Don’t adjust the burners yourself. Call in a pro.
Vacuum the Burners
Turn off the power switch again and shut off the gas by giving the valve one-quarter turn. Vacuum the burners and the furnace base. To get at the back of the burners, tape a 20-in. length of 1/2-in. drain line to your vacuum hose. Vacuum everywhere you see dust. While everything is open, use a flashlight to look for signs of soot (fine black powder), which often indicates poor combustion. Lift off the lower door (blower door) and vacuum the blower compartment.
Clean the Blower
Clean the blower blades thoroughly with a vacuum and small brush. Take care not to stress the wiring or disturb the counterweights that will be on the fan blades. If you can’t clean the blower thoroughly, don’t clean it at all; you could throw it off balance.
Clean the Pilot
Blow dust off the pilot. Direct air to the exact spot by blowing through a drinking straw. A dirty pilot can cause the flame sensor (or thermocouple) to get a false reading that the pilot isn’t lit. Some newer furnaces have hot surface igniters instead of pilots and electronic igniters. (Note: One burner was removed for clarity.)
Clean the Flame Sensor
The flame sensor occasionally becomes coated with residue and will prevent your furnace from lighting. Remove it by pulling it down out of its bracket. Lightly clean the surface with fine emery cloth and slip the sensor back into its bracket.
