Minnesota has some of the most stringent energy codes for heating equipment in the country — which makes sense given our climate. If you're installing a new furnace, your contractor must comply with current state and local energy codes, and understanding what's required helps you ask better questions and avoid surprises.
Minnesota Energy Code Overview
Minnesota adopts and amends the International Energy Conservation Code (IECC) for residential construction. The Minnesota Department of Labor and Industry (DLI) administers these requirements. As of the most recent adoption, Minnesota's residential energy code imposes specific efficiency minimums for heating equipment.
Minimum Efficiency Requirements
Gas Furnaces — New Installations
Minnesota follows federal minimum efficiency standards for gas furnaces, with some state-level enhancements. For residential gas furnaces installed in Minnesota:
- Non-weatherized (indoor) gas furnaces: Minimum 80% AFUE as the federal baseline — however, Minnesota's cold climate zone (Zone 6–7) means the 2021 IECC (and Minnesota amendments) effectively require 90% AFUE or higher for new construction and many replacement installations in northern Minnesota climate zones
- In most Minnesota counties: The practical standard for new installations is 90%+ AFUE minimum, with 96% being the dominant choice for efficiency, comfort, and economics
Check with your local building department for your specific municipality's requirements — some jurisdictions have adopted more stringent local amendments.
Federal DOE Regulations
The U.S. Department of Energy has proposed regional efficiency standards that would require higher AFUE minimums in northern states, including Minnesota. Federal rules have been in flux — confirm current federal minimums with your contractor, as these continue to evolve.
Permit Requirements
In virtually all Minnesota municipalities, replacing a furnace requires a mechanical permit. The permit triggers an inspection by a local building official who verifies:
- Equipment meets minimum efficiency standards
- Venting is proper for the equipment type (B-vent for 80%, PVC for 90%+)
- Combustion air supply is adequate
- Gas line connections are correctly made and leak-tested
- Electrical connections meet code
- Carbon monoxide detectors are present and properly located
Contractors who skip permits are creating serious liability for homeowners. Unpermitted work can void insurance claims and create problems at resale.
Carbon Monoxide Detector Requirements
Minnesota Statute 299F.50 requires CO detectors in all dwellings with fossil fuel appliances (including gas furnaces). Required placement:
- At least one CO detector within 10 feet of every sleeping room
- On every level of the home that contains a sleeping area
- In any room that contains a fossil fuel appliance if that room is adjacent to a sleeping area
CO detectors must be replaced every 5–7 years (check the manufacturer's expiration date on the unit).
Duct Sealing Requirements
Under Minnesota's energy code, ductwork in unconditioned spaces (attic, garage, crawlspace) must be sealed. When a new furnace is installed, it's common practice — and increasingly code-required — to seal accessible duct connections with mastic or UL-listed tape. Unsealed duct systems can lose 20–30% of conditioned air, dramatically reducing efficiency.
Thermostat Requirements
Minnesota's energy code requires programmable or smart thermostats in new construction and many replacement installations. Setback capability (ability to reduce heating during unoccupied periods) is the key requirement. Any modern digital thermostat meets this requirement — manual dial thermostats do not.
What This Means for Your Installation
When buying a furnace through Furnace Direct, you're selecting a Goodman unit — all of our models meet or exceed Minnesota energy code requirements. Our licensed installers pull permits, perform code-compliant installations, and ensure the work passes inspection.
Our most popular models for code compliance and value:
- Goodman GMVC96 — 96% AFUE, two-stage, meets all Minnesota requirements
- Goodman GMVM97 — 97% AFUE, modulating, exceeds all requirements
Related: Minnesota HVAC Rebates | Contractor Licensing Guide | How to Choose an HVAC Contractor
Do you know your model number?
Search your exact replacement — or let us match you to the right unit in 60 seconds.
Search by Model
Enter your furnace or AC model number to find your exact factory-direct replacement.
Take the 60-Second Quiz
Answer 4 quick questions and we'll match you to the right furnace for your home and budget.
🏠 Take the 60-Second QuizGet installed pricing on a new system.
Tell us a little about your home and what you're replacing. We'll send real numbers on a Goodman 96% AFUE setup — equipment shipped nationwide, licensed install in select metros. No contractor markup, no obligation.