Furnace Installation Day: What to Expect from Start to Finish

How Long Does a Furnace Installation Take?

A standard furnace replacement in Minnesota takes 4-8 hours for an experienced two-person crew. Simple swaps (same location, same fuel type, similar size) land at the low end. More complex jobs—moving the furnace location, adding new ductwork, upgrading to high-efficiency with new PVC venting—can extend to a full day. Plan to be home all day and have the HVAC system unavailable. In January, that means a cold house for several hours—factor that in.

Before the Crew Arrives

The new furnace should be delivered or staged (Furnace Direct provides same-day Minneapolis/St. Paul delivery); the contractor should have pulled the required mechanical permit; the gas company may need to be notified for service adjustments; clear the area around the furnace for working space—at least 3-4 feet on all accessible sides.

Step 1: Arrival and Assessment (30-60 minutes)

The crew does a walkthrough before touching anything: inspect existing system (ductwork condition, gas line size, venting route, electrical service), confirm the new unit fits, identify any code issues, and plan the work sequence. Photograph the existing installation before work begins.

Step 2: Shutoff and Disconnection (30-45 minutes)

Gas supply shut off; electrical power disconnected; thermostat wires labeled and disconnected; old furnace disconnected from ductwork, gas line, and venting; old unit removed. Good contractors remove everything—old unit, sheet metal scraps, packaging.

Step 3: Venting and Gas Line Prep (30-90 minutes)

If upgrading from 80% to 96% AFUE: contractor installs new PVC intake and exhaust pipes—this is the most variable part of the job. Gas line connection checked for correct pipe size (3/4" minimum) and proper shutoff valve. Gas pressure test performed after connection.

Step 4: Furnace Placement and Connection (1-2 hours)

New furnace positioned and leveled; ductwork connected (supply plenum on top, return air at side or bottom); PVC venting connected and routed to exterior; condensate drain connected for 96% units; gas line connected to furnace gas valve; electrical connection made (120V to furnace, 24V thermostat wires).

Step 5: Startup and Commissioning (45-90 minutes)

This is where quality installers separate from average ones. Should include: gas leak check on all connections before firing; combustion analysis (measures CO output, O2 levels, flue gas temp); static pressure measurement (verifies ductwork within spec for new blower motor); temperature rise measurement (should be within rated range, typically 35-65°F); gas pressure check at furnace gas valve; thermostat programming and verification. Quality contractors document all commissioning measurements in writing—ask for this paperwork. See our Goodman installation contractor checklist.

Step 6: Cleanup and Walk-Through (30-45 minutes)

All old equipment and debris removed; work area cleaned; contractor walks you through the new system (thermostat use, filter location, condensate drain access, error code LED meaning); warranty registration completed; permit inspection scheduled (inspector visits separately, typically within 1-4 weeks).

After Installation: What to Watch For

In the first few days: some dust burning off at startup is normal, gas smell is not (call immediately). Check for any error codes on the furnace LED (see our Goodman error codes guide), condensate leaks, and unusual noises. If the furnace goes into lockout within the first few heating cycles, call your contractor rather than just resetting it.

Browse our current Goodman furnace inventory with same-day Minneapolis/St. Paul delivery. Related: Furnace installation cost in Minnesota 2026 | How to compare HVAC quotes | Minnesota HVAC contractor licensing guide