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In almost every Fort Bend County house the furnace, the blower and the evaporator coil sit in one cabinet in the attic. Replacing the heating half in isolation is possible, and it is often the wrong shape of decision. Here is how to tell.
A conventional Fort Bend County system is a split system: a condenser outside, and inside — almost always in the attic, because a slab-on-grade house has no basement and no crawl space — a vertical stack containing the gas furnace, the blower that drives both seasons, and the evaporator coil sitting on top of it. One cabinet, one set of ductwork, one thermostat.
That physical arrangement is why a no-heat call in November on a fifteen-year-old house turns into a bigger conversation than the homeowner expected. Replacing the furnace section means opening the cabinet the coil sits on, disturbing the line set connections, and putting new equipment underneath a coil that is the same age as the thing being thrown away. Sometimes that is still the right call. Often it is spending most of the labor of a full changeout to renew half the system.
The questions that decide it: how old is the cooling side, what refrigerant is in it, and is the blower being replaced anyway. If the answers are fifteen years, R-22, and yes, the decision has effectively been made for you.
Furnace only, furnace and coil, or the whole system including the condenser. This should be the first line of the quote rather than something inferred from the price.
An attic furnace needs combustion air and a clear flue path. A higher-efficiency condensing furnace vents differently — PVC rather than metal flue — and produces condensate that needs somewhere to drain.
Sizing, the sediment trap, and the shutoff at the appliance. This is the part of the job where the trade overlaps with plumbing rules, and it is not a place for improvisation.
If the cabinet is coming apart anyway, the auxiliary pan, the secondary drain line and the float switch are being handled. The quote should say which of them are new.
Getting a furnace section out of a 2010s attic through a pull-down stair is genuinely part of the labor, and platforms and decking sometimes need work to meet the new footprint.
Inside Missouri City, Richmond, Needville, Meadows Place or Beasley there is a mechanical permit. In unincorporated county there is none. The city-by-city position.
A condensing furnace at 95%+ AFUE recovers its premium over an 80% unit through fuel savings, and how long that takes depends entirely on how much fuel gets burned. In a market with 961 heating degree days, it takes a long time — considerably longer than the same upgrade in Dallas, and very much longer than in Chicago. Anyone presenting a payback period here should be prepared to show the arithmetic on Houston consumption rather than on a national average.
What can justify the higher-efficiency unit locally is not usually the gas bill. It is the blower: higher-tier furnace sections are where variable-speed indoor motors live, and the variable-speed blower earns its keep for five months of the year on the cooling side, by running longer and slower and taking more moisture out of the air. Judging a furnace on its summer behavior sounds backwards and is exactly right in this county.
The other honest option is to leave gas out of it. Heat pump systems covers what changes when one machine does both seasons and there is no combustion, no flue and no heat exchanger to crack.
A July no-cooling call is made from a house at 92 degrees with an infant in it. A November no-heat call is made from a house at 61 degrees with a sweater available. The second one is uncomfortable rather than dangerous, which means there is time to get a second quote, read both warranties and ask what the load calculation says.
It is also a quieter month for the trade. Every heating contractor in Houston is busy for about two weeks after the first cold snap and comparatively free either side of it, which is a real scheduling advantage available to anyone who does not wait for the snap.
Physically yes, and sometimes it is the right answer — a young cooling side and an old furnace section is exactly that case. But in a Fort Bend County house the furnace, the blower and the evaporator coil share one attic cabinet, so replacing the furnace section means most of the labor of a full changeout. If the cooling side is the same age and uses R-22, the arithmetic usually points at doing both.
On fuel savings alone, the payback is long — Houston Hobby logged 961 heating degree days in 2025, so there is not much fuel to save. The stronger local argument is the blower: higher-tier furnace sections carry variable-speed indoor motors, and a variable-speed blower earns its money across five months of cooling season by running longer and slower and removing more humidity. Ask for the payback arithmetic on Houston consumption, not a national figure.
Inside a city, usually yes — Missouri City, Richmond, Needville, Meadows Place and Beasley all issue mechanical permits, and several require the contractor to be registered with the city first. In unincorporated Fort Bend County there is no county mechanical permit, because the county has not adopted building codes for single-family residential development. The contractor's state license is required either way.
Access, venting and consequences. Getting a furnace section in and out through a pull-down stair is real labor. Combustion air and the flue path have to be right in a space that is also full of insulation. And anything that leaks, condenses or overflows up there does so directly above a finished ceiling, which is why the condensate arrangement is part of a heating job rather than only a cooling one.
Longer than the air conditioning, because it runs far less — but the failure modes are driven by idleness and thermal cycling rather than by hours, so the advantage is smaller than the degree-day difference suggests. The practical constraint is usually the shared cabinet: the furnace section outlives the cooling side, and by the time it fails, the coil and blower beside it are already candidates for replacement.
If the no-heat call landed on a system past fifteen, this is a changeout discussion. Get connected with an independent, TDLR-licensed Fort Bend County contractor while there is time to compare quotes.
Call (346) 623-3250 Request a Quote
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