What does it cost to replace the furnace and AC together in Minnesota, and is it cheaper than doing them separately?
Replacing both with us costs $9,700–$19,300 installed: our furnace ($4,500–$9,500) and central AC ($5,200–$9,800) ranges added, with no package discount. When both are near the end, one project usually costs less than two, because the coil, sheet metal and startup are done once and the system is matched from the start.
Key points
- Furnace and central AC together with us: $9,700–$19,300 installed, our two ranges added.
- There's no package discount; the saving is coil, sheet metal and startup work done once instead of twice.
- Ask for the AHRI reference number to confirm the outdoor unit and coil are a certified match.
- AC equipment made since 2025 runs on R-454B or R-32 with its own coil; an R-410A system can't be converted.
- Split the job when one unit still has years left, and in Minnesota, put heat first.
Replacing the furnace and central air conditioner together costs $9,700–$19,300 installed with us, which is our furnace range ($4,500–$9,500) and our central AC range ($5,200–$9,800) added together, with no package discount. When both are near the end, one project still usually costs less than two, because the coil, the sheet metal and the startup get done once, and the furnace, coil and condenser are chosen as a matched system.
| Pairing | Installed with us (our ranges added) |
|---|---|
| 80% AFUE furnace plus central AC | roughly $9,700–$15,800 |
| 96–98% AFUE condensing furnace plus central AC | roughly $11,700–$19,300 |
| Furnace plus a heat pump in the AC's place (dual fuel) | $12,000–$24,000 |
Where a job lands depends on the same things that move each piece alone: furnace efficiency and staging, venting changes, the air conditioner's size and staging, whether the line set can stay, and the electrical work. Our guides to furnace replacement cost and AC replacement cost go through each list. This page covers what changes when the two are done as one job.
Why does replacing the furnace and AC together cost less?
The furnace and air conditioner cost the same whether they're bought together or years apart. The saving is labor that would otherwise happen twice. The air conditioner's indoor coil sits on top of the furnace, in the airflow. Replace only the furnace and the old coil usually has to come off, get refitted to the new cabinet (sometimes with a transition piece) and get reconnected. Then, when the air conditioner fails a few years later, the new condenser needs a new coil anyway, and the same corner of the basement gets taken apart again.
Doing both together means:
- one coil, sized and set on the new furnace once
- one sheet-metal transition, built to fit both
- one set of refrigerant connections, with the line set checked or replaced for the new refrigerant
- one startup, with the blower's airflow set for heating and cooling together
- one load calculation deciding both sizes (our AC sizing guide shows how that works)
The simplest way to see the difference for your house is to ask for the quote both ways: the furnace alone, and the furnace and air conditioner together.
Why does the AC coil need to match the outdoor unit?
An air conditioner's efficiency rating is certified for a specific outdoor unit and indoor coil working together. AHRI, the industry group that certifies those ratings, says split systems have to be properly matched to deliver the efficiency and service life you expect, and that a mismatch cuts into both. Its advice to homeowners is to ask the installer for an AHRI Reference Number or AHRI certificate, which confirms the outdoor unit and indoor coil were certified together. To look one up yourself, you need the manufacturer, model name and model number for both units.
The coil also has to suit the furnace under it: the same cabinet width, the same airflow direction (upflow, downflow or horizontal), and the refrigerant the condenser uses. Air conditioners manufactured since the start of 2025 run on lower-GWP refrigerants such as R-454B or R-32, and a condenser built for one of them needs a coil built for it. Lennox and Bryant both say an existing R-410A system can't be converted to R-454B. R-410A equipment built before 2025 can still be installed legally, and a working R-410A system can still be repaired and recharged, so nothing forces an early replacement.
New R-454B systems carry a refrigerant leak sensor. Carrier describes its version as a sensor that watches for leaks continuously and turns on a fan to disperse the refrigerant if it finds one. On a furnace-and-coil system, that fan is the furnace blower, so the coil's sensor and the furnace controls have to work together. The blower matters for comfort too: a two-stage or variable-speed air conditioner needs a furnace blower that can deliver its airflow at each speed, and long, slow cooling cycles are what pull humidity out of a July house.
When splitting it up makes sense
| Situation | What we usually suggest | Why |
|---|---|---|
| Furnace fails in winter; AC under 10 years old on R-410A | Replace the furnace now, keep the AC | The coil can usually go on the new furnace, and the AC gets replaced when it fails |
| AC fails in summer; furnace under 15 years old and healthy | Replace the AC and its coil now | The new coil has to fit the furnace, and the blower has to support the new AC |
| AC runs on R-22 and the furnace is aging too | Replace both, or pair a new furnace with a heat pump | The condenser and coil have to change anyway, and R-22 production and import ended in 2020 (R-22 options) |
| Furnace past 15 and AC past 10 | Replace both together | Both are past the ages ENERGY STAR flags |
| Money for only one | Heat first | A failed furnace in January is an emergency; a failed AC in July isn't |
The ages come from ENERGY STAR, which suggests considering replacement once an air conditioner passes 10 years or a furnace passes 15. They're prompts to get a price, not deadlines. If your furnace and air conditioner went in the same year, they reach those ages together. And if the air conditioner is the one that's due, heat pump vs furnace covers putting a heat pump in its place.
Minnesota timing, houses and rebates
- Timing. Heat decides the schedule here. A furnace that quits in a January cold snap gets replaced now, and the air conditioner can wait for spring if its coil fits the new furnace. If both are aging but still running, spring and early fall are the easy months to replace them together.
- Houses. In older Minneapolis and Saint Paul houses, a condensing furnace brings PVC venting and often a fix for a water heater left alone in the chimney, and converted gravity ducts can limit airflow for the new air conditioner. Our cost pages for Minneapolis and Saint Paul cover both cities' housing.
- Rebates. CenterPoint Energy, the gas utility in Minneapolis, runs heating system rebates for high-efficiency furnaces with the dealer of your choice. Xcel Energy's heating equipment rebates cover high-efficiency gas furnaces and cooling systems and point to participating contractors, and its cooling rebates follow quality-installation rules, so ask whether the rebate you want needs a registered contractor. The federal 25C tax credit ended for equipment placed in service after December 31, 2025. Our 2026 rebate guide links each program.
- Permits. Replacing a furnace or air conditioner normally needs a mechanical permit. We pull it and list it on the quote.
Safety stops before you decide
- If a technician finds a cracked heat exchanger or red-tags the furnace, leave it off. That settles the timing: the furnace gets replaced first, and the air conditioner decision can follow.
- Minnesota law (Minn. Stat. 299F.51) requires an approved, operational carbon monoxide alarm within ten feet of each room lawfully used for sleeping. Replacement day is a good day to test yours.
- If you smell gas, leave the house and call your gas utility or 911 from outside.
What should a combined furnace and AC quote list?
- the furnace model, efficiency and staging
- the outdoor unit and coil model numbers, with the AHRI reference number for the match
- whether the line set stays or gets replaced
- venting, condensate drainage and any water heater venting fix
- electrical work, the pad and the disconnect
- the permit
- startup checks for gas pressure, temperature rise, refrigerant charge and airflow
Installs carry our 2-year labor warranty on top of the manufacturer's parts warranty, and financing is available. Our furnace installation page shows what every install includes.
What to do next
Call 612-429-3465 (open 7 days, 7am–9pm) and ask for the quote both ways, furnace alone and furnace plus air conditioner, from one visit with a Manual J load calculation. If one of the two is only acting up, start with a repair visit: the $79 trip charge is waived when you approve the repair, and the written price tells you whether fixing it buys the time to replace both together later. Pricing is the same in every town we serve, and our pages on furnace installation in Minneapolis and AC installation in Saint Paul cover the local details.
Questions
Can a new furnace go under my old air conditioner coil?
Often, if the coil fits the new furnace's cabinet width and airflow direction and the air conditioner has years left. The coil usually has to come off, be refitted to the new cabinet and be reconnected, and the blower gets set for the air conditioner's airflow. When the AC fails later, the new condenser comes with its own matched coil, so that corner of the job gets done again.
Is there a discount for replacing both at once?
We don't advertise a package discount. Each piece is priced from the same published ranges: $4,500–$9,500 for a furnace and $5,200–$9,800 for central AC. What you avoid is paying for the coil, sheet metal, refrigerant connections and startup a second time a few years from now. Ask for the quote both ways, furnace alone and both together, and compare the totals.
Will a new R-454B air conditioner work with my existing furnace?
Usually, with a new coil. A condenser built for R-454B needs a coil built for that refrigerant, and an R-410A system can't be converted. The new system's leak sensor turns on a fan if it detects refrigerant, and on a furnace-and-coil system that fan is the furnace blower, so the furnace controls have to work with it. The blower also has to deliver the airflow the new AC needs.
Which should I replace first if I can only do one?
Heat. A furnace that fails during a Minnesota January is an emergency; an air conditioner that fails in July isn't. If the furnace is sound and the AC is dying, replace the AC with a coil that fits the furnace. If the furnace is failing and the AC has years left, keep the AC and set its coil on the new furnace, then plan the AC replacement for a spring.
Sources
- ENERGY STAR energystar.gov
- AHRI Directory of Certified Product Performance ahridirectory.org