Most HVAC installations can be completed in one day, depending on the complexity of the system and the home. Larger or more customized installations may take longer. Really it depends on the system and components. It can take longer to install a system correctly rather than ignoring hidden problems that will will cause comfort issues or cause big issues for you down the road. but generally:
- Furnace installs in 1 day
- Furnace and AC installs in 1-3 days
- Typical heat pump system 1-3 days
- Typical HVAC system and ducts 3-5 days

