Humidification Retrofits Deliver Residential Furnace Efficiency


About the webinar

Standard efficiency furnaces are robust, long-lived appliances — but they use 15% more natural gas than the current best available technology, and they are still being installed frequently today. They are seldom replaced by high-efficiency units before the point of failure, which implies hundreds of trillions of BTUs in missed energy savings over the next few decades.

To find a new way to increase the efficiency of standard furnaces, researchers looked at  transport membrane humidifier (TMH) technology, which can retrofit the standard older furnaces to make them as or more efficient than new furnaces. TMHs transfer waste heat and water vapor from flue gases into the building air supply. This improves efficiency and occupant comfort by adding humidity to dry winter air. The study tested TMH technology in four cold-climate sites to assess the lifetime energy savings potential for the state of Minnesota.

This webinar gives a technical overview of the field assessment, measured energy savings, occupant feedback, and evaluation of cost-effectiveness of transport membrane humidifier (TMH) technology. Study findings have the potential to support the development of new utility rebates and program integration and introduce contractors to a new service and value stream. Findings will also inform those looking for cost-effective standards for energy code adoption. 

Learn more about the research on the project page

Download the recording

Humidification Retrofits Deliver Residential Furnace Efficiency (mp4)
Humidification Retrofits Deliver Residential Furnace Efficiency from Center for Energy and Environment

Follow-up Questions 

Q. You mentioned you needed to obtain special signoff from code officials in order to install this technology. Is the technology currently in the process of receiving UL approval, or is will that still be an issue for someone who wants to install this device? 

A (JQ): Great question! The technology is not currently in the process of receiving UL approval. UL certification would typically be performed on the final commercial product prior to entering the market. It is an example of some of the additional costs associated with commercialization that potential manufactures identify as a risk.

Q: What kind of special training (if any) do you anticipate contractors will require in order to install this technology?

A (JQ): 
Another good question. I’m not sure I touched on this enough in the talk, but I was impressed at every stage by our contractors (CenterPoint Energy Home Service Plus). As part of the permitting process, we had to develop installation and operating instructions. We used that requirement as an opportunity to “test” our contractors. We gave them a set of instructions on the first installation and then maintained a hands-off approach during the installs and mainly served to document the process. these guys consulted the documentation briefly and then went at it. IT was clear right from the start that while the TMH was a different idea, it did not represent anything fundamentally different than their typical work on HVAC systems. In fact, the mechanical guys didn’t need instructions after the first install. Even though most of the installations varied in very significant ways – they varied in ways that are outside installation notes for all devices whereby good contractor judgement is the necessary requirement. The electrician typically just referenced the wiring diagram once at the start of his work. The success with this HVAC group was one of the more important finding in our study because it suggests that these installations are cheap and easy, and more important will not require special contractor training. 

This project supported in part by a grant from the Minnesota Department of Commerce, Division of Energy Resources through the Conservation Applied Research and Development (CARD) program. And with co-funding by CEE in support of its nonprofit mission to advance research, knowledge dissemination, and program design in the field of energy efficiency.