If Your Furnace Losing Efficiency?
You turn the heat on for the first time this week. It smelled like burnt dust for an hour, which is normal, and then it just kept running. The thermostat says 70 but your feet disagree. Plano furnaces sit idle most of the year, so the first cold snap is usually when one that’s been losing efficiency for a while finally gets caught.
What a Higher Gas Bill Is Telling You
Last winter a homeowner called me about her gas bill suddenly going up. It had gone from around $140 to just under $200, and she’d already done the detective work. Same thermostat setting, roughly the same weather. Nobody new living in the house.
She figured the furnace was dying. It wasn’t. The filter hadn’t been changed since the previous owners moved out, and the blower had been fighting it for two winters. New filter, and the next bill came back down.
That’s the good version. Sometimes the bill really is a furnace losing efficiency, sometimes it’s the ductwork, and sometimes the gas company just raised the rate. Check the rate line first. Takes thirty seconds.
Run Time Is the Easiest Thing to Watch
You don’t need tools for this one. Just a clock.
On a mild night, time a cycle from when the burners light to when they shut off. A healthy furnace usually finishes in ten or fifteen minutes, then goes quiet for a while. If yours runs half an hour and the house is still a degree short, something’s choking it or the furnace itself is slipping.
Or it does the opposite. On, off, on, off, every couple of minutes. A dirty flame sensor causes that a lot, and so does a clogged filter tripping the high-limit switch. Cleaning the sensor is a five-minute job for a tech, but it sits right in the burner area, so I’d leave it to one.
Don’t time it on the coldest night of the year, though. Everything runs long then.
The Cold Back Bedroom
Every house has one. Usually it’s the room farthest from the furnace, and usually the furnace gets blamed.
Check the vents and returns first. I’m serious. I once spent a good ten minutes in a guy’s attic before I came down and noticed his new bookshelf standing flush against the hallway return grille. He took it well.
If everything’s clear, the next suspect is the ductwork, usually flex duct that’s crushed or pulled loose up top. That’s an attic job, and I’d rather you didn’t. One step off a joist and you’ve got a hole in the ceiling to go with your cold room.
When I’d Start Thinking About Furnace Replacement
Plenty of the units I see around Plano rode out the February 2021 freeze and are still going. Age alone isn’t a reason to tear one out. A 17-year-old furnace that’s been looked after, with a fresh capacitor on the blower, can beat a rushed install.
What changes my answer is a pattern rising bills, a repair call every winter, and a unit losing efficiency even after a good tune-up. That’s when furnace replacement is worth pricing. Ask about the AFUE number on the new one. Higher means less of your gas goes up the flue.
And if a tech finds a cracked heat exchanger, the conversation’s over. That’s a carbon monoxide problem, not a budget one.
Call Before the First Hard Freeze
If a couple of these sound like your house, call Total Air and Heat now, while it’s still mild in Plano. A tune-up takes about an hour. A furnace losing efficiency that quits at 2 a.m. in January takes a lot longer to sort out. We’re Not Comfortable Until You Are.
Furnace Questions We Hear Around Plano
my furnace runs nonstop but the house is still cold, why
Usually airflow. Check the filter, then make sure nothing’s blocking the return grille. If both look fine, it could be a dirty flame sensor or a worn blower, and that’s worth a service call.
Is a dirty filter really that big a deal?
It’s the first thing I check, every time. A packed filter starves the blower, so everything runs longer and wears faster. Buy the size printed on the old frame, and skip the thick high-MERV ones unless your system’s built for them.
furnace is 18 years old, do I gotta replace it
Not automatically. If it passes a safety inspection and repairs aren’t stacking up, it can keep going. Talk furnace replacement when the repairs start coming every year or the heat exchanger cracks.
how do I tell if it’s the ducts or the furnace
Hard to tell from the thermostat. Crushed or leaky attic duct can make a healthy furnace look like it’s losing efficiency. A tech can check both in one visit, and you want that done before anyone quotes a new unit.
when should I get it checked
Early fall, before the first real cold front. Once the first freeze hits, every HVAC company in Plano gets slammed and you’ll wait. Once a year is plenty for most homes.
Go pull the filter tonight and hold it up to a light. If you can’t see through it, you’ve found your first problem.
