Building a Better PTAC

As a mechanical engineer, I design the HVAC systems and specify the heating and cooling equipment for multifamily buildings. Recently, my firm, Abraham Joselow, PC, has specialized in affordable and supportive housing in the New York Metro area.

Working on Department of Housing and Community Renewal (DHCR) projects poses unique challenges to the building design and specification process because they have been steadily tightening their environmental efficiency standards. Specifically, DHCR and other certification agencies, such as Green Communities, NYSERDA and LEED, are interested in better sealing the building envelope to improve energy efficiency as a whole.

In analyzing the many different components of a building’s envelope, there are numerous contributors to energy loss, including the wall sleeves of Packaged Terminal Air Conditioners (PTACs). I often specify PTACs because they are cost-effective units for heating and cooling multifamily residences.

One drawback of using PTACs is that the wall sleeves are typically made of sheet metal, which is highly thermally conductive and allows for thermal transfer.

As you can imagine, seasonal temperature variations cause thermal transfer through the PTAC sleeves into the building interior. To compensate for this transfer, the HVAC equipment must be run more frequently, lowering overall building energy efficiency, creating higher operating costs, and shortening equipment life span.

Eventually, DHCR stopped accepting PTACs in their projects because of the thermal transfer issue.  Around that time, I started working on a new housing development at 2701 Kingsbridge Terrace in the Bronx, and knew I needed to find a solution for the PTAC wall sleeve problem. The building, which was completed in 2012, is part of the Jericho Project’s Veteran’s Initiative to provide supportive housing to formerly homeless Iraq and Afghanistan veterans.

Unfortunately, there were no thermal break wall sleeve options for PTACs on the market. I’ve worked with the most prominent PTAC manufacturers in the industry, and so I approached many companies (I won’t name names here) to propose developing a continuous metal thermal break wall sleeve solution. No one would listen. Finally, one day I was discussing the issue with Mo Siegel, the co-CEO of Ice Air, and he said: “We can do that!” Ice Air went to work and created a thermally broken wall sleeve that virtually eliminates both conductivity and thermal transfer.

Ice Air named this product ThermalGuard,, and they now sell it as a standard accessory offering. I wish I had been the one to trademark it!

We used these  sleeves for the 75 PTACs at 2701 Kingsbridge Terrace, and have continued to use them in numerous other buildings since. If a project requires LEED certification or DHCR approval, I won’t specify PTACs without them because they make LEED projects easier and they improve the building envelope enough to meet DHCR standards.

I also worked with Ice Air to create an add-on Outside Air Module that cost-effectively provides filtered, tempered outside air through the PTAC units. This solution meets the required standards of fresh air intake into each unit and building, and is an energy efficient alternative to using window-mounted “trickle vents.”

The main lesson here is that it benefits everyone involved in the building process – including manufacturers – to be receptive to new ideas when it comes to using innovation and energy efficient products to solve problems.  

About the authors

Peter Joselow