New Air Duct System for Home HVAC

For nearly a century, plumbers mounted pipes the very same outdated way, laboriously slicing and soldering metallic pipes in the subject. Then, in the 1990s, a innovative content known as cross-joined polyethylene—better recognised as PEX—came along. 

As we know now, PEX is a flexible tubing that requires significantly much less fittings and no glue or solder to set up … and it doesn’t corrode. Some plumbers resisted PEX at initially, but ahead of very long understood the simplicity and speed of the process was greater for their bottom strains, devoid of sacrificing good quality. These days, PEX is the predominant plumbing system in new residential construction. 

Now, a new duct process is established to remodel the household heating and cooling sector in the exact way, thanks to early investments by the Creating Technologies Office environment at the U.S. Department of Electrical power (DOE). 


Building a New Air Duct Procedure for Home HVAC

Rheia, a new company that grew out of analysis funded in element by DOE’s Building The united states Plan, is partnering with some of the country’s major household builders to show a patent-pending “plug-and-play” air duct system intended to be mounted within conditioned area in today’s energy-effective new houses. 

The technique is made up of a manifold, uniform-diameter ducts, connectors, and diffuser factors that snap with each other to kind a nearly airtight delivery procedure without the need of the use of tape or mastic. The ducts are smaller adequate to match inside of wall cavities, generating it simple to keep duct runs within just conditioned room, which increases the performance and vitality performance of the overall system. 

The Rheia system’s ducts are little enough to suit within wall cavities, producing it quick to hold duct operates within just conditioned area. | Photograph: courtesy DOE Constructing The usa Program

Rheia is a great illustration of “lab-to-residing room” innovations that the Constructing The us program has been performing on for the past 25 a long time, a system that ordinarily commences with building science authorities tinkering around in their labs to at some point obtaining that innovation utilised by some of the most important builders in the place.

Addressing Several Air Duct Concerns at The moment

Common air duct programs are plagued with challenges:

  • They leak conditioned air 
  • They’re generally beneath-insulated and improperly installed 
  • When ducts run by unconditioned spaces this kind of as attics—as they usually do—they get rid of vitality, compromising the home’s energy performance and occupant ease and comfort.

Imagine of it this way: If you have a furnace rated at 90% effectiveness, but 30%of the air is leaking out just before it gets sent, it’s fundamentally functioning only at 60% effectiveness. Efficiency is not just about the devices it’s about the entire procedure.” 

Builders understand these troubles, but most really do not want to give up useful inside area for ducting that would at the very least incorporate leakage within just the building’s conditioned thermal envelope. It is also complicated to make dropped ceilings and soffits look very good.

In 2015, Pittsburgh-dependent IBACOS—a prolonged-time Developing The usa lover with approximately 3 decades of analysis on air delivery systems—partnered with the Housing Innovation Alliance on a Making The us job to function out the kinks. 

This photograph shows all of the tested products. The ducts are labeled quantities 1–10, and the two insulation sorts that were being employed are labeled 11 and 12. For this get the job done, PVC was the most important substance below thought nonetheless, 3-inch flexible duct supplies a code-recognized smaller-diameter content. Other supplies were analyzed as references and for exploration of possible solutions. Duct resources and insulation: 1: down spout 2: snap lock 3: 2.5-inch PVC 4: 2-inch PVC 5: aluminum flex 6: nylon fabric 7: 3-inch flexible duct 2 inches 8: 3-inch adaptable duct 3 inches 9: adaptable PVC 10: metal conduit 11: R-4.2 12: R-6.. | Photo courtesy DOE Developing The usa Method

Taking into consideration various suggestions, the group ultimately landed on a very simple, builder-pleasant “plug-and-play” duct program found within conditioned space. The procedure uses just five components in comparison with 18 for a traditional trunk-and-department HVAC duct method, and most of the components that connect the ducts are built with a fiberglass cloth around a coiled wire frame.

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In point, IBACOS utilised the “PEX model” when developing the program. “We experienced the thought that with very low-load properties we can use smaller ducts,” claims Andrew Poertschke, a Making General performance Professional for IBACOS. “If you faucet them all into a central manifold, it gives you much better and extra predictable airflow. As well as, you can fit them into conditioned room.” The program also works by using substantially much less factors than a common HVAC procedure.

Portion of the task was to develop a structure methodology for figuring out the size and variety of duct runs. Because the ducts are all the very same measurement, some rooms require additional than 1 duct operate even so, the simplicity of installation will save time.

From 2015 to 2017, IBACOS performed lab tests and modeling to validate the technological know-how. It built a mock-up of a two-tale townhome at the IBACOS Innovation Centre and applied it to assess content and labor fees for a trunk-and-branch HVAC system and two plug-and-participate in devices. Final results from this time-and-motion examine showed a significant drop in labor expenses for the plug-and-participate in method.

HVAC systems comparison
Resource: July 2017 report: “A Plug-and-Play Duct System Evaluation” / DOE Making The us

“As we labored additional with the procedure, we started to understand that this idea may well have a extremely robust labor worth proposition and could potentially revolutionize the marketplace,” Poertschke says. 

It was important that the ducts be compact enough to fit into wall cavities. Lab screening and modeling confirmed that most properties up to 4,200 square ft in local weather zones 3–5 could be sufficiently conditioned with 3-inch-diameter smooth ductwork. Smaller sized houses could be conditioned employing 2.5-inch or 2-inch ducts. 

To validate the modeling, IBACOS scientists installed the process in an unoccupied take a look at dwelling in Pittsburgh, monitoring it for airflow and comfort and ease knowledge. They also applied this HVAC duct installation to analyze irrespective of whether door undercuts have been suitable as the most important means for return air transfer (trace: they were being).

An Innovative Business enterprise Model 

At that stage, the IBACOS crew commenced pondering how to bring the solution to marketplace and talking about it with their dependable advisors, like Alan Laing. 

Laing, who has led many significant making companies, which includes a stint as VP of functions at Pulte Households, was enamored with the prospective for the project, sufficient so that he arrived on board to aid variety a new firm named Rheia. (The name is derived from the Greek “mother of the gods,” whom Laing phone calls the “Goddess of Ease and comfort.”) 

Rheia officially released in early 2019, with the purpose of bringing the plug-and-play duct system to industry in mid-2020. 

“There was a strategic interest in obtaining builders to be buyers due to the fact they are also the customers,” Poertschke says. “We knew we could generate gross sales extra quickly this way.” To date, Rheia has elevated money from eight of the greatest house builders in the place, along with more than 30 specific investors.

For the reason that the ducts are all the exact same dimensions, some rooms demand additional than just one duct run even so, the ease of installation will save time.

“A good deal of the uniqueness of the technological know-how arrives down to the parts and items,” claims Nigel Watts, Rheia’s VPof merchandise, who has a lot more than three decades of merchandise development abilities, which include a stint at IBACOS. “To access labor personal savings with an airtight system, we have performed a ton of engineering,” he provides. 

Even with the system’s amazing progress to day, “you simply cannot go into The Residence Depot and get a Rheia process off the shelf,” Poertschke states. As a substitute, the organization sells instantly to contractors and builders. Agreement makers make the factors, and source-chain application corporation IndustryStar Methods, which has comprehensive experience in the automotive sector, aids handle the source chain and makes certain the components are delivered to jobsites.

Into the Industry: Rheia HVAC Ductwork Gets a Exam Push in New Houses Nationally

Immediately after validating its efficiency, the future move was to pilot Rheia in new homes throughout the state.“We knew the process would work,” Poertschke states. “So we began heading into each and every market and seeing how the trades responded to it.”

In the course of 2020, Rheia worked with numerous property builders to put in the program in 13 households in different weather zones, which includes Baltimore, Indianapolis, Orlando, Fla., Pittsburgh, and San Diego. The corporation also employed this time to protected the demanded certifications from Underwriters Laboratories (UL) and supply injection molding and manufacturing capacity.

Rheia HVAC system installation
The Rheia system makes use of significantly much less components than a standard HVAC technique. | Image: courtesy DOE Building The us System

Comments from HVAC installers has been extremely good, Watts states. “It’s less complicated for them. It’s a lot less messy, safer, and more quickly.” 

The pilot systems have presented builders a possibility to examination-travel the process right before applying it on a greater scale. “It’s the very first stage in the profits procedure,” states Anthony Grisolia, taking care of director of Innovation for IBACOS. “Builders want to consider it out to validate the claims.” 

HVAC Innovation Test: Deliver on the Builders

1 of the participating investor builders was Pulte Properties, the nation’s 3rd greatest house builder, which was inspired to commit in the plug-and-enjoy program since of its commitment to innovation, but also since of its shut ties to IBACOS and its Complete system.

Soon after visiting the Pittsburgh test site, the household builder agreed to mock up the method for one particular of its flooring plans.“Being able to visualize the system was incredibly impactful,” suggests Jeff Townsend, nationwide procurement supervisor for Pulte Residences. 

By inserting the Rheia ducts in conditioned room, Pulte Homes was equipped to shrink the temperature differential by quite a few levels and downsize the program machines by half a ton.

Quickly soon after, Pulte resolved to pilot the technique in a single of its households in Orlando, Fla. The installation was done in May well of 2020. Immediately after building, Pulte monitored the residence to make guaranteed it was providing the envisioned amount of convenience, simulating unique disorders as if the house was occupied.

There have been queries, Townsend admits. The process seems a bit unique. Air comes out of the registers in a circular pattern alternatively than straight forward. However, he suggests that fulfilling buyers calls for deconstructing how HVAC is completed: that is, to cease forcing air by means of warm attics and eliminate the “imperfect design” of the mixing box. “With common duct methods, you frequently stop up overheating or overcooling one particular facet of the dwelling,” Townsend states. 

On regular, regular systems result in a seven-degree temperature variation from one part of the home to another. By placing the Rheia ducts in conditioned space, Pulte was in a position to shrink the temperature differential by a number of levels and downsize the system machines by half a ton—a considerable cost and strength cost savings. A RESNET HERS Rating examination also revealed that acquiring the ducts in conditioned space yielded an enhancement of 4 to 5 scores factors. 


Pulte’s Orlando take a look at property offered at the end of 2020. The organization plans to adhere to up with the new house owners all over the coming year. “We want to realize what this process does for our homeowners,” Townsend states. The corporation has also initiated a pilot in Indianapolis for a method that presents both equally cooling and heating and is wanting at other areas to establish where by the technique will ideal be utilized.

Responses from the pilot households is getting used to tweak some of the bodily components to make them easier to install and to reconsider some of the system’s aesthetics. 

In the meantime, after a second spherical of fundraising, Rheia’s subsequent action is transitioning from the pilot phase to a creation design towards viewing several more new residences applying the plug-and-participate in HVAC system that ultimately presents the marketplace a solution builders will use and their prospects will like.


About Constructing America’s Analysis-to-Market System

The U.S. Section of Vitality (DOE) Setting up The united states Application has spurred improvements in constructing performance, toughness, and affordability for much more than 25 several years. Elevating a clear power economic climate and skilled workforce, this earth-course research method companions with industry to leverage cutting-edge science and deployment options to lower property vitality use and enable mitigate local climate adjust.

The Making The usa Investigate-to-Current market Program discovered 3 built-in street maps:

Each individual of these street maps is designed to strategically deal with the integrated issues similar to reaching huge adoption of energy-successful and healthy high-general performance homes.

Eric Werling is countrywide director of the Building The usa application for the U.S. Office of Electrical power. He’s an skilled in household electricity performance, indoor air high-quality, and building sciences and is targeted on reaching zero carbon emissions in the future 10 years.