Furnace Replacement HVAC Companies

The Sizing Myth: Why a Bigger Furnace Heats Worse

Furnace capacity is measured in BTUs, and the right number comes from a Manual J load calculation - a room-by-room measurement of your home's actual heat loss through walls, windows, insulation, and air leakage.

What a Manual J visit looks like

The estimator measures rooms, checks window types and insulation depth, and feeds it into load software. It takes an hour or more. The output is a BTU number your house needs on its coldest design day - usually smaller than what is currently in the basement, because most old furnaces were oversized on installation.

Short cycling: the oversized signature

A furnace that runs five minutes, stops, and restarts all evening is oversized. Short cycles are the hardest duty a furnace can pull - igniters, boards, and heat exchangers all age fastest at startup.

The red flag

If a bid arrives sized by square footage alone, walk. That single shortcut predicts how the rest of the install will go.

Efficiency Tiers: 80% vs 96% AFUE in Real Dollars

AFUE is the share of fuel that becomes heat in your house. An 80 percent furnace typically installs for $3,500 to $6,000; a 96 percent condensing furnace runs $5,000 to $9,000.

Where the extra efficiency comes from

Condensing furnaces add a second heat exchanger that wrings heat out of the exhaust until it literally condenses - which is why they drain water and vent in PVC through a side wall instead of a metal flue.

Climate math

In a cold-climate home burning $1,200 of gas a winter, the 16-point AFUE jump saves roughly $200 a year and pays back its premium in six to ten years. In a mild climate with a $350 heating season, it may never pay back - an honest estimator will say so.

Fuel Choices: Gas, Electric, Oil, and Propane

Natural gas dominates where it is piped; propane and oil carry higher fuel costs and electric resistance furnaces cost little upfront but the most to run. Converting fuels changes more than the furnace - gas lines, tanks, venting, and electrical service all move the bid. If your electricity is cheap or your gas is expensive, read the heat pump vs furnace fork before committing to another 20 years of burner - one read, before the equipment is ordered, is enough.

Single-Stage, Two-Stage, or Modulating

A single-stage furnace is on or off. A two-stage runs low most of the time and high on cold snaps - longer, gentler, quieter cycles for $800 to $1,500 more. Modulating furnaces adjust in small increments and pair with variable-speed blowers for the steadiest comfort, at flagship prices. The comfort gain is real; whether it is worth it depends on how uneven your house feels today and how long you plan to stay.

Install Day, Hour by Hour

A straight changeout is a one-day job - typically six to ten hours without heat, which is why installers schedule around weather.

Tear-out through first heat

Morning: old furnace disconnected and hauled out, sheet metal transitions fabricated, gas line and venting adapted - PVC sidewall venting if you jumped to 96 percent - and the condensate drain run. Afternoon: electrical, thermostat, and startup.

Commissioning: the proof

A proper install ends with measurements, not a handshake: gas pressure set to spec, temperature rise inside the nameplate range, static pressure checked, and combustion analyzed with a CO reading. Ask for the commissioning numbers in writing - installers who do the tests are glad to show them.

Permits and Inspections a Legitimate Install Includes

Furnace replacement is gas work, venting work, and electrical work - permit territory in nearly every jurisdiction. The permit costs little; the inspection is a second set of eyes on combustion safety. Unpermitted furnace installs surface at resale, when buyers' inspectors ask for paperwork that does not exist. The contractor pulls the permit; a bid that leaves it to the owner is telling you something.

What Happens to Your AC Coil and Ductwork

The evaporator coil sits on top of the furnace, and a new blower pushing through a 15-year-old coil is a mismatch - most installers recommend replacing the coil at the same time for a few hundred dollars more instead of paying separate labor later. If the load calc found duct problems, fixing them now, while everything is open, is the cheapest that work will ever be. For the full heating-and-cooling budget picture, see what full-system replacement costs.

Old-Furnace Disposal and Your First Season

Haul-away and disposal should be a written line item, included in most bids. Expect faint burn-off smells and new noises in the first days - oils from manufacturing cooking off the heat exchanger are normal; sharp chemical smells or a tripping CO alarm are not, and warrant a call. Register the equipment within the manufacturer's window to lock the 10-year parts warranty, then put the furnace on a fall maintenance rhythm from day one.

When you are ready for bids, get three sizing-included quotes and compare them against the top-rated HVAC companies - the installers who measure first are the ones worth letting touch gas.