If you are considering moving from a conventional furnace and air conditioner to a heat pump, the useful thing to know is what happens between the first conversation and a working system.
Here is the sequence, and what should happen at each stage.
Quick answer: A heat pump conversion happens in four stages: an assessment with a load calculation, a written proposal, installation day and commissioning to confirm the system runs to spec. A well-planned heat pump conversion can also keep your existing furnace as backup for the coldest days.
The most important visit, and the one most often rushed.
Load calculation. The heating and cooling load calculated from your house — square footage, ceiling heights, insulation, window area and orientation, air leakage, layout. Not from the size of the old equipment. This matters more with a heat pump than a furnace because heat pumps are sensitive to sizing in both directions. Full detail in our guide to HVAC sizing and Manual J.
Duct evaluation. Heat pumps deliver heat at a lower supply temperature than furnaces, which means moving more air for the same warmth. A duct system built for a furnace may not have the capacity. Static pressure gets measured, return sizing gets checked, and any modifications get identified now rather than discovered later.
Electrical assessment. The panel needs capacity for the outdoor unit and, if applicable, backup heat.
Envelope review. Insulation and air sealing affect sizing significantly. Sometimes the honest advice is to address the attic first, which lets you install smaller equipment and get better results.
Configuration. Straight heat pump with electric backup, or dual fuel with your existing or a new gas furnace. With natural gas service in a Michigan home, dual fuel is usually worth serious consideration.
A proper proposal specifies which equipment, what capacity, what efficiency ratings, what backup heat configuration, what duct or electrical work is included, and what the changeover strategy is.
If a quote is a single price with a brand name and nothing else, ask for the details. The details are where the difference between systems lives, and our guide on how to compare HVAC quotes walks through what should be itemized.
One thing to be clear about: the federal 25C tax credit that covered heat pump installations through 2025 expired on December 31, 2025. Equipment placed in service in 2026 does not qualify. Utility and state programs are separate and change by program year, and we cover the current picture in Michigan HVAC rebates in 2026.
Preparation. Floor coverings go down along the work path. Items blocking access get moved or protected.
Removal. The old outdoor unit gets disconnected and refrigerant is recovered properly rather than vented, which is both a legal and an environmental requirement. Old equipment is taken for recycling.
Indoor work. The new indoor coil gets installed and the plenum modified as needed. On dual fuel the coil sits above the furnace. On a full conversion, an air handler replaces the furnace entirely.
Line set. New refrigerant lines get run, or the existing set is evaluated and reused only if it is the correct size and can be properly cleaned. Reusing an undersized line set limits the system permanently.
Outdoor placement. Set on a pad or an elevated stand. In Michigan, elevation matters — a heat pump runs in winter and produces condensate during defrost, and that water needs somewhere to go without building an ice dam under the unit.
Evacuation. The lines get evacuated to a deep vacuum and held, confirming no leaks and no moisture in the system. This is the step that gets skipped by installers in a hurry, and it is the leading cause of premature compressor failure. Moisture in a refrigerant circuit forms acid. The consequences arrive two or three years later, long after anyone connects them to the install.
Thermostat. A control capable of heat pump logic and, on dual fuel, changeover management. Compatibility details in smart thermostat compatibility.
Installation is not finished when the system turns on. It is finished when it is verified.
Refrigerant charge confirmed by superheat and subcool readings. Airflow measured and adjusted. Temperature differential checked in both heating and cooling modes. Defrost cycle verified. Changeover point set and tested. Backup heat operation confirmed.
Then a walkthrough: how the thermostat works, what the defrost cycle looks and sounds like so you are not alarmed the first time, filter location and schedule, and what to expect from supply air temperature.
Supply air feels different. Warm rather than hot. The house reaches the same temperature. Most people stop noticing within a couple of weeks.
Longer run cycles. A variable-speed heat pump running steadily for long stretches is working as designed, and steady operation gives better comfort than short bursts.
Defrost cycles. In cold damp weather the outdoor unit periodically reverses to melt frost off the coil. Steam, a click from the reversing valve, a temporary pause in heating. Normal.
Different utility bills. Electric use rises, gas or propane use falls. Comparing them together is the only meaningful comparison.
J&J has installed heating and cooling across Southwest Michigan for over 50 years, and we handle heat pump conversions throughout Calhoun, Kalamazoo, Barry and the surrounding counties. Estimates are free, and if a conversion is not right for your house we will say so.
A straightforward changeout is typically one day. Projects involving duct modification, electrical upgrades or a switch from furnace to air handler can run two days or more.
Often yes, if it is in good condition and can be controlled properly in a dual fuel configuration. That gets confirmed during the assessment.
Sometimes, particularly if you are adding electric resistance backup heat. The electrical assessment during the site visit determines whether an upgrade is needed.
Thinking about a heat pump conversion? J&J can walk you through every stage, from the load calculation to commissioning.
Schedule service online or get in touch at (269) 965-1627 today! Prefer to pick a time yourself? Book your visit online.
9000 M-66 South • East Leroy, MI 49051
(269) 965-1627
Monday - Friday: 8:00am - 5:00pm
