How Long Does HVAC Installation Take?

Most HVAC installations finish in a single day. A straightforward furnace or AC replacement takes 4 to 8 hours. A full system swap takes 1 to 2 days. Boilers and complex multi-zone mini-split systems can run up to 3 days. Here is what to expect for each equipment type.

Installation Time by Equipment Type

Equipment	Typical Installation Time
Gas furnace replacement	4 to 8 hours
Central air conditioner	4 to 8 hours
Full HVAC system (furnace + AC)	1 to 2 days
Ductless mini-split (single zone)	4 to 6 hours
Ductless mini-split (multi-zone, 3-5 heads)	1 to 2 days
Tank water heater	2 to 4 hours
Tankless water heater	4 to 8 hours
Boiler replacement	1 to 3 days
Heat pump system	1 to 2 days

Furnace Installation: 4 to 8 Hours

A like-for-like furnace replacement is one of the faster HVAC jobs. The crew disconnects and removes the old unit, sets the new furnace, connects gas and electrical, attaches ductwork, and tests operation. If you are upgrading from 80% to 96% AFUE efficiency, the team also needs to run new PVC vent piping, which adds 2 to 4 hours.

Central AC Installation: 4 to 8 Hours

Replacing an air conditioner involves swapping the outdoor condenser, installing or replacing the indoor evaporator coil, connecting refrigerant lines, and testing the charge. If the existing refrigerant lines and electrical are compatible, the job stays on the shorter end. Older R-22 systems being replaced with R-410A or R-454B equipment may need new line sets, adding time.

Full System Replacement: 1 to 2 Days

When you replace both the furnace and air conditioner together, expect a full day or two. The first day typically covers removal and furnace installation. The second day handles the outdoor unit, coil, and system testing. Some crews complete both in a long single day if the existing ductwork and electrical are in good shape.

Mini-Split Installation: 4 Hours to 2 Days

A single-zone ductless mini-split from Mitsubishi or Fujitsu takes 4 to 6 hours. The installer mounts the indoor head, places the outdoor unit, drills a 3-inch hole through the wall, runs the line set, and commissions the system. Multi-zone systems with 3 to 5 indoor units take 1 to 2 days because each head needs its own line run, mounting, and electrical connection.

Water Heater Installation: 2 to 8 Hours

A tank water heater swap is one of the quickest jobs: 2 to 4 hours to drain the old tank, disconnect it, set the new one, and connect water, gas, and venting. Tankless water heater installation takes longer at 4 to 8 hours because the job often requires upgrading the gas line size, adding new venting, and installing a condensate drain. Switching from tank to tankless for the first time adds the most time.

Boiler Installation: 1 to 3 Days

Boiler replacements are the most labor-intensive residential HVAC job. The old boiler needs to be drained and disconnected from the hydronic piping, gas, venting, and electrical. The new boiler goes in, all connections are remade, the system gets filled and bled of air, and every zone gets tested. Cast iron to cast iron swaps take 1 to 2 days. Switching from a cast iron boiler to a wall-hung condensing unit like a Navien can take 2 to 3 days because the piping configuration changes significantly.

Heat Pump Installation: 1 to 2 Days

A ducted heat pump system replaces both your heating and cooling equipment. Installation time is similar to a full furnace-plus-AC replacement: 1 to 2 days. If you are adding a heat pump to an existing furnace as a dual-fuel system, expect the job to land on the shorter end since the furnace stays in place.

What Can Add Time to Your Installation

• Permits: Pennsylvania municipalities require mechanical permits for most HVAC work. McCorry handles the permit process, but inspections may add a day to the overall timeline.
• Ductwork modifications: If existing ducts are undersized, damaged, or poorly routed, adding or replacing ductwork can add a half day to a full day.
• Electrical upgrades: Heat pumps and some high-efficiency equipment need dedicated circuits or panel upgrades. An electrician visit adds time.
• Older Philadelphia homes: Rowhomes and pre-war houses often have tight mechanical spaces, outdated gas piping, or asbestos insulation that needs professional abatement before work begins. Budget an extra half day to a full day for these situations.
• Equipment access: Attic or crawl space installations take longer than basement or utility closet setups. Getting equipment up narrow stairways or through tight openings slows the crew down.
• Code upgrades: If your existing installation does not meet current code, the inspector may require upgrades to gas piping, electrical, or venting before signing off.

How to Keep Your Installation on Schedule

• Clear the area around your current equipment before the crew arrives.
• Make sure someone is home for the start and finish of the job.
• Keep pets in a separate area away from the work zone.
• Ask your installer about permit timelines before scheduling.
• If you live in an older home, mention that during the estimate so the crew can plan for surprises.