Where the furnace lives tells you its era: Gainesville furnaces by decade, and what each needs every fall

Three furnaces, three houses

The historic closet. Across the Duckpond, Pleasant Street and the Southeast Gainesville Residential District, homes built between 1890 and 1930 were heated by fireplaces, then floor furnaces, then whatever fit the old chimney chase. Today many have a gas furnace in a hall closet built for something smaller, venting through a liner in a century-old chimney, with ducts added in the 1980s or 1990s. The fall risks are venting, combustion air in a tight closet, and condensate from a high-efficiency unit draining through a floor that was never meant to get wet.

The 1970s garage. The largest cohort in Gainesville’s housing stock, nearly one home in five, dates from the 1970s, with another sixth from the 1980s. Northwest Gainesville, Suburban Heights and the earliest streets of Haile Plantation are full of them. The furnace is typically in the garage beside the water heater, breathing the same air as the lawnmower and the paint cans, with an outdoor air conditioner coil sitting on top. The risks are rust from garage humidity, corroded flame sensors, and a heat exchanger that is now forty years into its life if nobody has replaced it.

The sealed attic. In the Town of Tioga, Oakmont and the newer phases of Haile Plantation, furnaces are horizontal units on attic platforms, often in foam-insulated attics that stay reasonably cool. Modern, efficient, well-vented. The risks are different: condensate pumps and traps, pressure switch tubing, control boards sensitive to lightning, and a warranty that lapses without documented annual service.

Only about one Gainesville home in ten was built after 2010, so most fall furnace visits are to the first two houses.

What you can check yourself before calling

Work through this list in October, before the first cold front.

1. Find the furnace and clear around it. Three feet of space, nothing stored against the cabinet, no cans of anything flammable within reach. In a garage furnace this step alone prevents problems.
2. Change the filter. If the return filter is at the furnace, pull it and look at the arrow; if it is at a wall grille, same thing. Gainesville’s late-winter oak pollen will load the next one by March, so plan a second change.
3. Look at the vent. For a metal flue, check for rust streaks, white powder or sagging joints. For PVC on a high-efficiency unit, make sure the outside termination is clear of leaves, mulch and wasp nests.
4. Run it for ten minutes. Set the thermostat five degrees above room temperature. You should hear the inducer, then a click, then the burners, then the blower. A burning-dust smell for a few minutes is normal the first time. Count how long until warm air arrives at the farthest vent.
5. Check the condensate. On high-efficiency furnaces, water should drip steadily from the drain while it runs. None, or a puddle, means a problem.
6. Test the carbon monoxide detector. Every gas-heated home needs one on each floor, and it needs a battery.

Stop and call when you find

• Any smell of gas, at any time. Leave the house and call GRU’s gas emergency line or your propane company before calling anyone else.
• A carbon monoxide alarm, even a brief one.
• Burners that light yellow or orange rather than mostly blue, or flames that lift and flutter.
• The furnace lighting and shutting off repeatedly without warming the house.
• Soot or scorch marks around the burner door or vent connection.
• Water at the base of the cabinet.
• A vent pipe that is loose, rusted through or disconnected.
• Anything you cannot identify. Furnace work is not a weekend project; the combination of gas, flame and carbon monoxide is why.

Book a fall furnace visit

What Cook’s does on the visit

• Inspects the heat exchanger with a camera and tests for carbon monoxide at the supply registers and the vent.
• Cleans burners, the flame sensor and the igniter area; checks igniter resistance.
• Verifies gas pressure at the manifold and adjusts to specification.
• Tests the inducer motor, pressure switch, limit switches and rollout switches.
• Inspects venting and combustion air; in historic closets this is a careful step.
• Cleans or replaces the filter and inspects the blower wheel and motor; records amperage.
• Flushes the condensate trap and drain on high-efficiency units and tests the pump if there is one.
• Measures temperature rise and compares it to the nameplate range, which reveals airflow and duct restrictions.
• Checks the thermostat’s heating configuration and cycles the system through several complete runs.
• On electric furnaces, energizes and measures each strip and sequencer.
• Leaves a written report, with the camera findings described.

After the visit

The report goes to you with anything that needs repair priced separately and anything to watch noted for next year. Gas furnaces need this visit once a year, before the heating season; the air conditioner or heat pump that shares the ducts needs its own in spring. Keeping the record matters: manufacturers usually condition the heat exchanger and parts warranties on documented annual service, and a Cook’s report is written to satisfy that. Customers on a Cook’s agreement get the fall visit scheduled for them and member pricing on anything found; the Gainesville agreement’s details remain to be confirmed by the owner. [[CONFIRM WITH JERRY]]

Between visits, the homeowner’s job is the filter, the clearance around the cabinet and the detector battery. That is enough to get most Gainesville furnaces from one October to the next without a December surprise.