Furnace installation on Long Island. Load-calculated sizing, gas furnaces $5,500-$9,500 installed, free estimates.
A new gas furnace costs $5,500–$9,500 installed for most Long Island homes. High-efficiency condensing models carry a premium of roughly $1,000–$2,500, and ductwork modifications add to the total when the existing trunk lines need work. Every replacement estimate is free, in writing, with no obligation.
The most expensive mistake in furnace installation is not the brand or the efficiency rating. It is size. An oversized furnace short-cycles: it roars on, satisfies the thermostat in minutes, and shuts down before the house warms evenly, wearing out the heat exchanger and ignitor years early. We run a Manual J load calculation on the actual house — insulation, windows, orientation, air leakage — instead of matching the BTU number on the old unit. In Bethpage and the surrounding gas-served neighborhoods, we routinely find furnaces a full size class larger than the home needs, usually because a previous installer rounded up to be safe.
Sizing also decides comfort in a way homeowners feel every day. A correctly sized furnace runs longer, quieter cycles that keep bedroom temperatures steady, which matters in the split-level and high-ranch layouts common across both counties. If your ducts are part of the problem, we will say so and price the fix separately — see our ductwork repair service for what that involves.
Timing matters more than most homeowners expect. A furnace chosen calmly in October is priced and scheduled on your terms; the same decision made during a January failure happens under pressure, with whatever equipment is available that week. If your current unit is past fifteen years and repairs are becoming a pattern, a free estimate now puts a written number in the drawer for the day you need it. Winters on Long Island reward that kind of preparation.
An 80% AFUE furnace vents into a chimney; a 96%+ condensing furnace vents through PVC in the sidewall and squeezes more heat from every therm. On Long Island gas rates, the condensing premium typically pays back in roughly five to ten years depending on how hard the winter works your system — faster in a drafty Brentwood colonial than in a tight newer build. The ENERGY STAR program publishes the efficiency math if you want to check our numbers, and we walk through the payback with you during the estimate rather than defaulting everyone to the top-tier unit.
We install furnaces from all the major manufacturers — Carrier, Trane, Lennox, Rheem, Goodman, York, Bryant and American Standard — and we will tell you plainly which line fits your budget and which parts availability looks like a decade from now. The install quality matters more than the nameplate: a mid-tier furnace set up with correct gas pressure and airflow outperforms a premium unit installed carelessly.
Estimates are free, and the price you approve is the price you pay. If a hidden condition changes the scope, we stop and talk before any extra work happens.
| Job | Typical Long Island Price | Notes |
|---|---|---|
| Gas furnace, installed | $5,500 – $9,500 | Most Long Island homes; permit and disposal included |
| High-efficiency upgrade | $1,000 – $2,500 | Premium for 96%+ AFUE condensing with PVC venting |
| Ductwork modifications | $500 – $2,000 | Plenums, transitions and returns where needed |
| Replacement estimate | Free | Written price, no obligation |
Ranges reflect typical Nassau and Suffolk pricing. Your exact price is quoted upfront after diagnosis. Prices as of August 2026.
Most straightforward replacements are done in one working day. Add time when a chimney liner, gas line change or significant ductwork modification is part of the job; we tell you the schedule in the written estimate.
Size comes from a Manual J heat-loss calculation, not square footage alone. Two houses of identical size can need very different furnaces depending on insulation, windows and air leakage, which is why we measure instead of guessing from the old nameplate.
Usually, if you expect to remain in the house five years or more. The condensing premium of roughly $1,000–$2,500 pays back through lower gas bills, and homes with high heating usage recover it fastest. We show you both prices and the estimated payback so the choice is yours.
Yes. Furnace replacement requires a permit and inspection in Long Island townships, and unpermitted work can surface as a problem when you sell the house. We file the permit and meet the inspector as part of every installation.
Carrier, Trane, Lennox, Rheem, Goodman, York, Bryant and American Standard. We quote more than one option when it makes sense, and we are equally comfortable servicing whichever brand you choose for the life of the unit.
In most cases yes, with modest transition work at the plenum. If the ducts are undersized or leaking badly we will show you the measurements, because a new furnace pushed through bad ductwork never delivers its rated comfort or efficiency.
Honest repair-or-replace math.
Airflow measured, not guessed.
Permitted, pressure-tested gas work.
Everything we repair, install and maintain across Long Island.
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