Direct Replacements

Direct Replacement HVAC units are a Seasons•4 specialty. We can custom-engineer an HVAC system for almost any need. Seasons•4 excels at finding ways to upgrade old systems to provide better performance and efficiency while yet still meet the original footprint and match existing utilities.

Direct replacement multi zone units:

Seasons•4 is the largest manufacturer of direct replacement multizone units in the United States, manufacturing replacement units for older Carrier, Nesbitt, Lennox, and Trane multizone units as well as many others. Our units are built to match the existing curbs and utilities minimizing downtime allowing for quick and easy renovation projects. We have improved greatly upon the design and functionality of the older versions by utilizing direct drive blowers, modulating gas furnaces, modulating scroll compressors that reduce energy consumption while not sacrificing space comfort. We build two deck, three deck, and three deck vav versions of all units and many can be provided with energy recovery as well and still maintain the existing footprint.

Direct replacement for school markets:

Seasons•4 is a leader in direct replacement of old obsolete HVAC equipment for K-12 schools throughout the United States with some of the largest school districts relying on us for their replacement needs. Approaching school retrofit HVAC projects from a direct replacement standpoint can be beneficial to all parties. We recognize that “time is of the essence” in these applications, so meeting the footprint and matching the utilities helps all involved to get the units swapped out and up in running over a summer, or even over a school break.

High rise office buildings:

Below is a time lapsed video replacing an old 230 ton Tempmaster air handling unit on a Saturday. The customer closed their high rise building on Friday afternoon and come back to a fully functional unit on Monday. Seasons•4, Inc. is one of the last if not THE LAST manufacturer of large format air handlers and package DX units. Time lapse video is courtesy of Noble Associates.

Below is another replacement of an older penthouse unit. This is a 290 ton Package air cooled DX unit replaced by Seasons•4. The new unit shipped to the job site completely piped and charged with refrigerant, dramatically reducing installation time and costs.


Below is a Helicopter rigging of a direct replacement single zone unit. Seasons•4  measured the units on this project and a direct replacement built allowing the contractor and owner to quickly and easily install 42 new units on a mall in Michigan without interrupting their shopkeepers. Seasons•4, Inc. is a great choice for direct replacement HVAC units and even more so on “time is of the essence” replacements where HVAC system operation is critical.

General assembly of a Direct replacement multizone unit

Take a look at our 3D model and animated assembly video detailing components and assembly of a typical replacement multizone unit.

Before  and After

Alton HVAC unit

Alton SZ Package Unit tired and ready for replacement.

Seasons 4 Alton Direct replacement

Seasons 4 replacement placed into service

Seasons 4 has years of experience replacing existing Octagon Air Systems, Nesbitt, Carrier™, Trane™, and Lennox™ multizone units just to name a few.

The advantages of Seasons•4 replacement units include:

  • A Seasons•4 engineer completely measures the old unit.
  • Seasons•4 guarantees the unit to fit the curb and the duct connections
  • The unit will arrive on-site at the time you choose
  • The pre-charged and tested unit is ready for immediate installation and operation
  • A Seasons•4 technician will be on-site to assist in the rigging procedure
  • The installation for one unit should not exceed 8 hours
  • The unit can interface with most control systems