What does it cost to replace the furnace and AC together in Minnesota, and is it cheaper than doing them separately?
Replacing a furnace and AC together costs $9,700–$19,300 installed with us, our two ranges added. When both are near the end, one project usually costs less than two, because the coil, sheet metal and startup happen once and the system is matched.
Key points
- Furnace and central AC together with us: $9,700–$19,300 installed, our two ranges added.
- Doing both together saves on 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 AC in one project means one coil set on the new furnace, one sheet-metal transition, one set of refrigerant connections and one startup, with the furnace, coil and condenser 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)
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 built since the start of 2025 use lower-GWP refrigerants, mainly R-454B or R-32, and a condenser made for one of them needs a coil made for it. Lennox and Bryant both say an existing R-410A system can't be converted to R-454B. Nothing forces an early replacement: R-410A equipment built before 2025 may still be installed, and a working R-410A system can still be repaired and recharged.
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 confirm whether the rebate you want requires a registered contractor. The federal 25C credit is gone for equipment placed in service after December 31, 2025. Our 2026 rebate guide links each program.
- Permits. A furnace or air conditioner swap normally needs a city mechanical permit, so ask how the quote handles and prices it.
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.
- Minn. Stat. 299F.51 calls for an approved, working carbon monoxide alarm within ten feet of each bedroom, and replacement day is a good day to test yours.
- A gas smell means leave the house first, then 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
- how the permit is handled
- startup checks for gas pressure, temperature rise, refrigerant charge and airflow
Our 2-year labor warranty on installs adds to the manufacturer's parts warranty, and financing is available on installs. The furnace installation page lists what an install covers.
What to do next
Call 612-429-3465 (open 7 days, 7am to 9pm) and ask for both quotes, 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, a repair visit comes first: the $79 trip charge is waived when you approve the repair, and the written price shows whether fixing it buys time to replace both together later. Our pages on furnace installation in Minneapolis and AC installation in Saint Paul cover the local details.
Common questions about pricing
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.
How old is too old for a furnace or air conditioner?
ENERGY STAR suggests considering replacement once an air conditioner passes 10 years or a furnace passes 15. Those ages are prompts to get a price, not deadlines. If both went in the same year they reach those ages together, which is when pricing the two as one project, with one coil, one transition and one startup, is most likely to save money.
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; venting, condensate drainage and any water heater venting fix; electrical work, the pad and disconnect; how the permit is handled; and startup checks for gas pressure, temperature rise, refrigerant charge and airflow.
Sources
- ENERGY STAR energystar.gov
- Minnesota Statutes 299F.51 (carbon monoxide alarms) revisor.mn.gov
- AHRI Directory of Certified Product Performance ahridirectory.org
- Xcel Energy Minnesota heating and cooling rebates mn.my.xcelenergy.com
- Carrier manufacturer documentation carrier.com