Gas furnaces deliver high-capacity, low-cost heating for homes and light commercial buildings on natural gas or propane. Cedars HVAC Supply stocks 80% AFUE and 96% AFUE condensing furnaces in 40,000 to 120,000 BTU capacities, priced for contractors and commercial buyers.
80% AFUE vs. 96% AFUE
An 80% AFUE furnace converts 80% of the fuel it burns into usable heat and vents through a conventional metal flue. A 96% AFUE condensing furnace extracts additional heat from the exhaust with a secondary heat exchanger, vents through PVC, and produces condensate that needs a drain. The 96% models cost more up front but cut fuel use roughly 17% — the payback is fastest in colder climates and in buildings that run long heating seasons.
BTU Sizing Basics
Furnace capacity is rated in BTU per hour of input. Common guidelines:
- 40,000 BTU — Up to roughly 1,000 sq ft
- 60,000 BTU — Roughly 1,000–1,600 sq ft
- 80,000 BTU — Roughly 1,600–2,200 sq ft
- 100,000 BTU — Roughly 2,200–2,800 sq ft
- 120,000 BTU — Roughly 2,800–3,500 sq ft
Always run a Manual J load calculation rather than sizing by square footage alone. Climate zone, insulation, ductwork, and window area all shift the result, and an oversized furnace short-cycles, wastes fuel, and wears out faster.
Cabinet Orientation and Airflow
Most of our furnaces are multi-position, meaning the same cabinet can be installed upflow, downflow, or horizontally to suit a basement, closet, attic, or crawlspace. Match the furnace blower to the cooling coil’s airflow requirement (typically 350–400 CFM per ton) so the same air handler works for both heating and cooling.
Pairing a Furnace With Cooling
A gas furnace handles heating only. For year-round conditioning, pair it with an evaporator coil and a matched condenser, or consider a packaged gas/electric unit that combines both in a single cabinet.
Shop gas furnaces at Cedars HVAC Supply — free shipping on orders over $99. Questions? Call (305) 850-6693 or visit our contractor pricing page.


