Assessment of Through-the-wall Condensing Furnace/AC Packages

Ben Schoenbauer, Alex Haynor

Project Update
The project team completed the assessment and evaluation at its first site and the preliminary results are promising — the unit performed to expected factory standards and there were no programs with occupant comfort, condensate, or icing. Savings calculations indicate a simple payback of about 2.7 years. Full project update

Why This Research Is Needed

In the last year, four of the five major manufacturers of through -wall furnace/air conditioner packages have introduced condensing heating products with up to 95% AFUE or thermal efficiency (TE) rating. While these products are in an early commercialization phase, they have the potential to deliver significant energy savings to Minnesota utilities and utility customers compared to conventional, non-condensing systems with 80% AFUE.
This project will demonstrate the effectiveness of these through-wall condensing packages for high-efficiency gas heating in Minnesota multifamily buildings through a field assessment of through-wall furnaces and an evaluation of installations and unit performance. The results will help identify opportunities to improve market penetration of high-efficiency heating products with the growing use of through-wall furnace technology in multifamily buildings.

Project Process and Expected Outcomes

Project staff will conduct a field assessment of through-wall furnaces, which will include work with contractors, distributors, designers, and code officials to identify unresolved issues and devlop solutions related to the installation and operation of condensing through-wall units. To do this staff will perform field visits at one or two buildings with condensing through-wall furnaces and one or two buildings with standard efficiency through-wall furnaces. As condensing through-wall HVAC units are a new technology in the early commercialization phase, this phase will focus on addressing unresolved installation and utilization issues such as integration with ductwork and distribution, building and energy codes,  exterior and balcony aesthetics, and any building design modifications.
thru-wall-inside-pic.jpgIn the second phase, the project team will perform onsite measurements at one to two sites of combustion efficiency, airflow, and air temperature to verify installation quality and the installed performace. Based on results from both phases, the team will produce case studies and conduct trainings summarizing the findings from the field evaluation as well as potential opportunities to improve market penetration. 

Project Info

Complete in late 2017

Demonstrate the effectiveness of through-wall condensing HVAC packages in Minnesota multifamily buildings through a field assessment and onsite measurements and performance evaluation of installed units.
Non-Energy Benefits
  • Improved occupant comfort.
  • Variable speed supply fan resulting in quieter operation.
Utility Implementation
The results will help utilities identify savings and increase market penetration.

  • Perform field assessments of both condensing and standard efficiency units at 2-4 sites.
  • Measure and verify installation quality and performance of 1-2 sites. 

CEE Contact
Ben Schoenbauer

This project is supported by CenterPoint Energy