How Applied Comfort Fits Non-Standard Wall Sleeves

Published October 15, 2026 by Philly PTAC, powered by Air Distributors Company, Inc.

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Most PTAC manufacturers build one sleeve size and expect your wall to match. Applied Comfort works the other way. It builds PTAC chassis to the sleeve sizes already in older buildings, so you replace the unit without cutting the wall.

The problem Applied Comfort solves

A building with non-standard sleeves has a narrow set of choices when a unit fails. The original manufacturer may be out of business or out of the PTAC market. A standard 42 x 16 unit does not fit. Rebuilding the wall opening means masonry work, new sleeves, new grilles, and a room out of service for days.

Applied Comfort builds replacement chassis in sleeve families that match those older openings. The new unit slides in, connects to the existing power or piping, and the room is back in service.

Which sleeves Applied Comfort fits

Applied Comfort builds in several sleeve families. Each family covers a group of older units that shared similar dimensions. Examples include:

  • 32 inch wide sleeves, such as those used by some Zoneaire, Keeprite, and Islandaire models
  • 36 inch wide sleeves, used by some Zoneaire, Climate Master, and Islandaire models
  • 44 inch wide sleeves, used by some McQuay, Singer, Remington, and Islandaire models
  • Three-piece K series installations, originally from Singer, Remington, and McQuay
  • Series 16 style sleeves, originally from AAF and McQuay
  • Standard 42 x 16 sleeves with hydronic coils, in slope-top, flat-top, top-coil, and bottom-coil versions

This is not a complete list, and a brand name alone does not guarantee a fit. Dimensions decide it. Send your sleeve measurements and the old model number, and the match is confirmed before you order.

How the fit works

A replacement chassis has to match four things about the old installation.

1. Sleeve dimensions

Width, height, depth, and top shape. The chassis is built to slide into the opening with the right clearance and seal against the sleeve.

2. Outdoor airflow

The condenser has to pull air through the existing outdoor grille and push it back out. The chassis layout is designed around the grille pattern of the original sleeve family, so the existing grille stays in place.

3. Heat source connection

For electric heat and heat pump units, the chassis connects to the existing power. For hydronic units, the hot water coil sits in the same position as the original, top or bottom, so the supply and return piping connects without rework.

4. Electrical and controls

The chassis is built for the voltage your building supplies, 208/230V or 265V. Select series support a 24V remote wall thermostat for rooms that used one.

Hydronic heat in older Philadelphia buildings

Many Philadelphia apartment buildings from the 1950s through the 1980s heat with a central boiler. The through-the-wall units in those rooms cool with their own compressor and heat with a hot water coil fed by the boiler.

Replacing those units with standard electric PTACs moves heating from the building's boiler to each room's electric circuit. That raises electric demand, may require electrical upgrades, and changes who pays for heat. Hydronic replacements avoid all of that. The building keeps heating the way it was designed to.

Built to order

Many legacy chassis are built to order rather than stocked. Plan for that:

  • Order before the season you need them. Heat failures in winter and cooling failures in summer are the worst times to wait.
  • Keep spare chassis on site if your building has many units of the same legacy size.
  • For multi-unit projects, confirm the full quantity up front so the order builds in one run.

Some series are periodically redesigned. If a series is between production runs, the distributor tells you the expected availability with your quote.

A typical example

Picture a 1970s apartment building with 120 through-the-wall units on 44 inch sleeves, heated by hot water from a central boiler. The original manufacturer no longer builds the unit. Three units failed last winter, and maintenance has been cannibalizing parts from the worst units to keep the rest running.

The owner measures one sleeve, photographs a nameplate, and sends both with the heat type and quantity. The replacement is a hydronic chassis built to the 44 inch sleeve, with the coil connections in the original position. The building orders six units now to cover failures and keep two spares, then schedules the rest by floor over the next two years. No wall is cut, and no apartment loses heat for more than the time it takes to swap a chassis.

When to convert instead

A replacement chassis is the right answer in most occupied buildings. Converting to standard 42 x 16 sleeves makes sense when:

  • The existing sleeves are rusted through or out of square
  • The building is being gutted and rooms are empty
  • You are moving the whole building away from boiler heat

For the comparison in more detail, see standard vs. legacy PTAC sizes.

What to measure and send

  1. Inside sleeve width, height, and depth, to the nearest quarter inch
  2. Sleeve top shape, flat or sloped
  3. The old unit's brand and model number, with a nameplate photo
  4. Voltage, amperage, and whether the unit plugs in or is hardwired
  5. Heat type, and for hydronic units, top or bottom coil connections
  6. Quantity

The replacement guide covers each measurement. When you have them, see Applied Comfort replacement PTAC units, then request a quote or call 800-866-1210.

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