Furnace System GuideLennox and Goodman sit at different points of the market, but both publish high-efficiency modulating furnaces near the top of the AFUE range. This page collects the specs each brand states on its own site and notes where they differ on paper, without picking a winner.
How to Read This Comparison
The specs below come from each manufacturer's own furnace pages. Brands describe their lineups differently and advertise AFUE as an up-to figure, so exact one-to-one matching is imperfect and a specific installed model may not reach the top number.
AFUE only measures how much fuel becomes heat. It says nothing about price, warranty registration terms, comfort features, or the quality of the local install, all of which shape a real buying decision.
Where a brand did not publish a value on the page reviewed, this comparison omits it rather than guessing.
Lennox, As Published
Lennox positions the SLP99V Variable-Capacity Gas Furnace, from its Dave Lennox Signature Collection, at the top of its line and describes it as the quietest and most efficient furnace you can buy. It lists the SLP99V at up to 99.0 AFUE.
The SLP99V runs as a variable-capacity, modulating furnace and uses what Lennox calls Precise Comfort technology with variable-speed operation. A step down, the SL297NV Variable-Speed model reaches up to 97.5 AFUE and is described as a first-in-class, lowest-emission furnace.
These are the figures Lennox publishes on its furnace pages as of this review.
Goodman, As Published
Goodman's high-efficiency flagship is the GMVM97, which its product page lists at up to 98% AFUE. It is a variable-speed ECM modulating gas furnace that pairs a tubular aluminized-steel primary heat exchanger with a stainless-steel secondary heat exchanger.
Goodman explains its efficiency tiers in dollar terms, stating that a 90 percent or higher AFUE rating means more than 90 cents of every energy dollar warms your home. On coverage, Goodman references a 99-Year Heat Exchanger Limited Warranty and a 10-Year Parts Limited Warranty on its furnace pages.
These are the figures Goodman publishes on its furnace pages as of this review.
Where They Differ on Paper
On advertised top AFUE, Lennox lists a higher ceiling than Goodman: up to 99.0 AFUE for the SLP99V versus up to 98% for the Goodman GMVM97. Both flagships are modulating furnaces with variable-speed blowers, so the operating concept is the same at the top of each line.
Where the published pages diverge most is warranty framing. Goodman states a 99-Year Heat Exchanger Limited Warranty and a 10-Year Parts Limited Warranty on its pages, while the Lennox furnace pages reviewed did not disclose warranty length. That absence is a difference in what each brand publishes, not a measured difference in coverage.
The specs alone do not decide which furnace fits a given home. Installed price, dealer availability, and registration requirements all sit outside these numbers.