Furnace research site published with type, brand, and cost framework.
Editorial buildCitedIndependent furnace research
Heat your home with evidence, not sales pressure.
Compare gas, electric, oil, and high-efficiency furnaces by how they actually fit your home and climate, then check brand AFUE efficiency, stages, blower type, warranties, and local installers before you buy or repair.
Find a local professionalDecision paths
Start with the decision you need to make.
Verifiable furnace and home heating research.
Size the heat load
Know your heating BTU load before choosing any furnace size.
System typeChoose a furnace type
Match a gas, electric, oil, or high-efficiency furnace to your home and fuel.
Evidence fileResearch brands
See what each brand documents for AFUE efficiency, stages, and warranty.
Decision tableCompare options
Weigh brand against brand and gas versus electric versus high-efficiency.
Cost guidesEstimate costs
Understand repair and replacement cost before you get quotes.
DirectoryFind a local pro
Browse source-checked installer profiles by metro before requesting quotes.
Research method
Don’t start with a product.
Good furnace decisions start with the home and the heat load, not a product. This site is built to route you through system type, then model evidence, then a local installer.
- 01Size the heat loadHeating BTU load from a Manual J calculation, home size, insulation, and climate zone set the shortlist.
- 02Name the fuel and typeGas, electric, or oil, and single-stage, two-stage, or modulating.
- 03Verify the modelConfirm AFUE efficiency, BTU output, blower type, stages, and warranty for the exact model.
- 04Confirm the installerCheck gas line, venting, electrical, permits, and who handles the load calculation.
System reference
Compare the job each system actually does.
Each system family does a different job. Match the family to your ducts, climate, and electrical panel before comparing brands.
| Furnace family | Fuel | Typical efficiency | Best fit | Key consideration |
|---|---|---|---|---|
| Gas furnaces | Natural gas or propane | 80 to 98 percent AFUE | Homes with gas service | Venting and gas line |
| High-efficiency condensing | Natural gas or propane | 90 to 98 percent AFUE | Cold climates, long-term savings | Condensate drain and PVC venting |
| Electric furnaces | Electricity | 100 percent efficient at unit | No gas service, mild climates | Operating cost per kWh |
| Oil furnaces | Heating oil | 80 to 90 percent AFUE | Rural homes without gas | Oil tank and delivery |
Current brand library
Research the brands buyers encounter most.
Each brand review separates documented efficiency, warranty, and serviceability facts from claims that stay unverified.
Carrier
Independent brand review with cited AFUE efficiency, stage, blower, and warranty evidence.
Brand reviewTrane
Independent brand review with cited AFUE efficiency, stage, blower, and warranty evidence.
Brand reviewLennox
Independent brand review with cited AFUE efficiency, stage, blower, and warranty evidence.
Brand reviewGoodman
Independent brand review with cited AFUE efficiency, stage, blower, and warranty evidence.
Brand reviewRheem
Independent brand review with cited AFUE efficiency, stage, blower, and warranty evidence.
Brand reviewBryant
Independent brand review with cited AFUE efficiency, stage, blower, and warranty evidence.
Research standards
Trace the claim back to its evidence.
Every claim is tied to a primary source and a verification date. Where a figure is not documented, it is left marked unknown.
- 01Manufacturer documentationSpec sheets, AFUE ratings, BTU output, and warranty PDFs.
- 02Independent certificationAHRI certification records where applicable.
- 03Installation scopeGas line, venting, condensate, electrical, and permit requirements.
- 04Ownership and entityFilter, maintenance, and service responsibility boundaries.
Recently verified
What the research actually established.
Updates are dated so you can see how recent the underlying evidence is.
Local intelligence
Research nationally. Hire locally.
Research the equipment nationally, then hire locally. Installer profiles publish only source-checked provider facts.
Open directoryDenver, Colorado
75 Degree Heating & Air
- City
- Denver, Colorado
- Service areas
- Denver, CO
- Last checked
- 2026-08-29