Furnace and AC Replacement Cost: What to Expect in 2026

Replacing your air conditioner and furnace at the same time is one of the biggest home-comfort investments you will make, but it is often the smartest way to do it. Sharing one installation visit, one set of permits, and one ductwork assessment typically costs less than doing the two jobs separately. This guide covers what a combined AC and furnace replacement costs in 2026, when it makes sense, and how to decide between a combined system and a heat pump.

What does furnace and AC replacement cost together?

A combined AC-plus-furnace replacement costs more than either unit alone, but less than replacing them in two separate projects because the contractor shares the labor, refrigerant connection, thermostat wiring, and ductwork inspection across both pieces. The total depends on AC tonnage, furnace efficiency (80% vs 96% AFUE), your state, and ductwork condition. Estimate the combined cost with the AC + furnace cost calculator.

When should you replace both at the same time?

The strongest case for doing both at once is when both units are aging — roughly 12+ years — and one has already failed. Replacing just the failed unit leaves you with a mismatched system and a second replacement visit within a few years. Matching the units also ensures they are properly paired for efficiency: a high-SEER2 condenser paired with an old, low-efficiency air handler delivers less savings than a matched set.

If one unit is relatively new (under 7–8 years) and the other has failed, replacing only the failed unit and confirming compatibility with the surviving one is usually the better value.

Combined system vs heat pump

A heat pump replaces both the AC and the furnace in one unit, which makes it a natural alternative to a combined replacement. In mild to moderate climates (zones 2–4), a heat pump often costs about the same installed and less to operate. In cold climates (zones 5–7), a combined AC-plus-high-efficiency-furnace may still be the practical choice, especially if you have cheap natural gas. Compare the running costs with the heat pump vs furnace calculator.

How to save on a combined replacement

Three practical moves. First, get at least three bids specifically for the combined job — contractors price combo work differently than individual units. Second, schedule in spring or fall when demand is lowest. Third, check for utility rebates that apply to the combo: some programs offer rebates on the AC and furnace separately, and combining them doubles the incentive. Use the rebate finder for current programs in your state.

Frequently asked questions

How much does it cost to replace an AC and furnace together?

A combined replacement costs more than either alone but less than two separate projects. Use the AC + furnace cost calculator for a range based on your state, tonnage, and furnace efficiency.

Should I replace my AC and furnace at the same time?

If both are over 12 years old or one has failed and the other is aging, replacing both together saves on labor and ensures a matched, efficient system. If one unit is relatively new, replace only the failed one.

Is a heat pump better than AC plus furnace?

In mild to moderate climates a heat pump often costs about the same and runs cheaper. In cold climates with cheap gas, a combined AC-plus-furnace may still be practical.