Furnace Buying Guide: How to Compare Models and Choose the Right One

Shopping for a furnace can feel overwhelming. You're facing a wall of specifications—AFUE ratings, BTU outputs, stage counts, motor types—and a range of prices from $700 to $3,000+ for the equipment alone. This guide cuts through the jargon and gives you a practical framework for choosing the right furnace for your Minnesota home, your comfort priorities, and your budget.

Step 1: Get the BTU Size Right First

Before comparing any models, you need to know how many BTUs your home requires. This is the most important decision and the one most often skipped. A properly sized furnace:

• Runs in longer, more efficient cycles (less short-cycling wear)
• Maintains consistent temperatures throughout the home
• Doesn't overheat the heat exchanger on short cycles

A formal Manual J load calculation is the gold standard. As a rough guide for Minnesota:

• Well-insulated 1,000 sq ft: ~40,000–50,000 BTU/hr
• Average 1,500 sq ft: ~60,000–80,000 BTU/hr
• Average 2,000 sq ft: ~80,000–100,000 BTU/hr
• Larger 2,500+ sq ft: ~100,000–120,000 BTU/hr

If you've recently added insulation or air sealing, your actual load may be lower than this guide. Always get a calculation rather than just replacing with the same size.

Step 2: Choose Your AFUE Target

In Minnesota, the answer is almost always: 96% AFUE. Here's why:

• The incremental cost of 96% vs. 80% equipment has narrowed significantly
• Minnesota's 8,000+ heating degree days mean you consume a lot of gas—every efficiency point matters
• 80% AFUE furnaces vent through B-vent; 96% furnaces require PVC sidewall venting. If you're already doing the installation, adding PVC venting is a modest additional cost that pays for itself quickly in fuel savings
• Some Minnesota utilities don't offer rebates for 80% AFUE equipment at all—only for 96%+

The only exception: propane users with very budget-constrained situations where the higher equipment cost of 96% doesn't pencil out vs. the fuel savings. Even here, 96% typically wins at Minnesota's heating degree days—see our propane vs. natural gas guide.

Step 3: Single-Stage, Two-Stage, or Variable-Speed?

This is where you balance comfort vs. cost. Here's the practical breakdown:

Single-Stage (96% AFUE)

• Runs at 100% capacity every cycle
• Lower upfront cost ($150–$300 less than two-stage)
• Best for: smaller homes, tight budgets, homes where the furnace is well-away from living areas
• Goodman model: GMEC96

Two-Stage (96% AFUE)

• Runs at ~65% capacity (low stage) for most of the season; full capacity only when needed
• Quieter, more consistent temperatures, 5-10% more efficient than single-stage
• Best for: most Minnesota homes over 1,200 sq ft; open floor plans; two-story layouts
• Goodman models: GMSS96 (PSC blower), GMVC96 (variable-speed blower)

Variable-Speed Blower

• ECM motor continuously modulates airflow; dramatically quieter; 60-75% less electricity use for fan operation
• Best combined with two-stage gas valve (as in the GMVC96)
• Best for: larger homes, homes where the mechanical room is near living areas, homeowners running the fan continuously for filtration

See our full variable-speed vs. single-stage comparison.

Step 4: Compare Key Specifications Side by Side

When comparing specific models, focus on:

• AHRI Certified AFUE: The actual tested efficiency (not just the marketed number)
• Input BTU rating: This is the gas consumption rate; output BTU = input × AFUE
• Cabinet dimensions: Confirm the furnace fits your mechanical room (height, width, depth)
• Minimum external static pressure rating: Relevant if you have restrictive ductwork
• Venting requirements: 2" vs. 3" PVC; verify your installer knows the requirement for the specific model
• Warranty terms: Registered vs. unregistered warranty; length of parts warranty vs. labor warranty

Step 5: Consider the Total Installed Cost

The furnace price is only part of the equation. A complete installed cost includes:

• Equipment cost
• Installation labor (typically $600–$1,200 in Minnesota)
• New PVC venting (if upgrading from 80% to 96%): $200–$500
• Condensate pump or drain modifications: $100–$200 if needed
• Gas line work (if sizing needs to change): $200–$600 if needed
• Permit: $75–$200
• Minus: Utility rebates and federal tax credit

Factory-direct purchasing through Furnace Direct reduces the equipment component by $800–$1,800 vs. contractor-supplied equipment, while keeping all other components the same. Browse our complete Goodman furnace selection to compare factory-direct pricing across single-stage, two-stage, and variable-speed models.

Goodman Furnace Lineup: Quick Reference

• GMEC96: Single-stage, 96% AFUE, PSC blower. Best value entry point
• GMSS96: Two-stage, 96% AFUE, PSC blower. Mid-tier comfort upgrade
• GMVC96: Two-stage, 96% AFUE, variable-speed ECM blower. Top tier comfort and efficiency

Full reviews: GMEC96 review | GMSS96 review | GMVC96 review

Contact Furnace Direct with your home size and we'll help you identify the right model and BTU rating for your specific Minnesota home.