Sizing comes before the model number
Houston has a small heating load and a large cooling load, which creates a specific trap. Size the furnace by copying the old nameplate, or by taking whatever heating capacity comes bundled with the right size air conditioner, and it ends up considerably larger than the house needs.
An oversized furnace satisfies the thermostat quickly, shuts off, and repeats. That short cycling gives you uneven temperatures, more wear on ignition parts, and a house that feels drafty while the heat is running. We calculate the actual heat loss for your house and size to that.
What we look at besides the furnace
The furnace is one component in a system, and the rest of it usually decides how the new one performs. We measure static pressure and look hard at return capacity, because a blower that cannot move its rated airflow will overheat a furnace and starve an air conditioner in the same house.
We also check gas pipe capacity for everything connected to it, the flue and combustion air, the electrical supply, and attic access and drainage. A condensing furnace makes acidic condensate that needs a planned route to a drain, decided before install day rather than improvised on it.
Gas furnace, heat pump, or both
On the Gulf Coast this is a real question. A heat pump handles most of a Houston winter comfortably because it is your air conditioner running in reverse, and the same equipment carries the summer. A gas furnace produces hotter supply air and does not care how cold it gets outside.
Dual fuel pairs the two and switches to gas below a chosen outdoor temperature. Which is right depends on whether you already have gas at the house, what your air conditioner is doing, and how the last hard freeze went for you. We price all three rather than pushing one.
Install day and commissioning
We build the transitions properly instead of forcing a new unit onto a plenum that never fit, then commission it: manifold pressure set to specification, temperature rise verified against the data plate, static pressure measured, safeties tested, carbon monoxide checked. Replacement is permitted work, and our licence number, TACLA36229C, goes on the paperwork.
What we look at before quoting a replacement
- Actual heat lossWe calculate what your house loses on a design-cold night instead of copying the old nameplate.
- Duct and return capacityStatic pressure and return sizing decide whether any new furnace can move the air it is rated for.
- Gas line and drip legThe piping has to carry the whole connected load, not the furnace considered on its own.
- Venting and combustion airFlue type, sizing, slope, and a real source of combustion air, verified before equipment is chosen.
- Condensate routeA condensing furnace needs a planned, trapped path to a drain for acidic condensate.
- Electrical and accessSupply, disconnect, and whether the attic or closet can be serviced later without a fight.