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Green Builder Media and prefab home manufacturer Dvele have partnered to create Transcend Communities: net zero, all-electric, healthy, resilient, connected, solar-powered, and cost-effective homes located in mixed-use communities — and Minnesota-based manufacturer Uponor has played a pivotal role in this process, providing an in-floor radiant system that will heat and cool both air and water.

The partnership will launch with a demonstration home located in the San Juan Mountains of Colorado. The home also has a whole-home proactive IAQ system and radon detector to ensure healthy air, as well as water-conserving plumbing fixtures, leak detection, water monitoring systems, water filtration systems, and hot water recirculation systems.

“The whole home indoor air system includes an ERV and ventilation fans,” said Sara Gutterman, CEO and founder of Green Builder Media.

The ERV serves the fresh air exchange in the whole home ventilation, and the ventilation fans are for spot ventilation.

“If you have radiant heating and cooling, it's important to have that IAQ system, because a good thing about forced air systems, or even some of the ductless mini splits systems, is that they do help purify and filter air with filtration systems, and there's a lot of high-efficiency HVAC systems that now use really good filters to filter out particles in the air,” Gutterman said.

Due to the Transcend Homes prefab manufacturing, the homes can be manufactured, delivered, and installed onsite in under six months, providing some relief regarding the skilled labor shortage and supply chain challenges.

Radiant Heating and Cooling

This is Green Builder Media’s 21^st demonstration project, and majority of them use radiant heating and cooling because of its efficiency. Plus, since Transcend Communities are working from a baseline of net-zero homes and energy-smart infrastructure, the homes all need to feature products and systems that not only help in reducing operational greenhouse gas emissions, but also support decarbonization efforts.

The communities will feature geothermal heat pumps that connect to the radiant heating and cooling system.

“Radiant heating and cooling systems are a perfect fit due to their energy efficiency and comfort as well as their ability to work well with geothermal and heat pump heating and cooling technologies that already exist in the communities,” said Aaron Stotko, director, Segment marketing, at Uponor.

RADIANT: Uponor radiant panels being installed in the demonstration home. (Courtesy of Green Builder Media)

“So in terms of meeting sustainability goals … because you're using the earth as your main heating and cooling source, you're really reducing carbon emissions,” Gutterman said. “It's helping to make these communities net zero carbon, as well as net zero energy.”

The Transcend homes will be conditioned by ceiling-based radiant systems, which are able to provide better performance when using the radiant system for cooling while still providing the same benefits as a radiant floor system when they are in heating mode. The radiant systems can be used in zones, allowing occupants to alter the comfort settings for precision based on what rooms are occupied, reducing energy and cost. They also keep the indoor air clean, operating without the transfer of allergens, viruses, and odors throughout the space.

A common misconception with radiant cooling is that the radiant surfaces will develop condensation due to humidity.

“In practice, and from a thermodynamic standpoint, that’s an easy myth to debunk,” Stotko said. “A 75°F dry bulb at 65% relative humidity (RH) has a 62°F dew point temperature. While 65% RH is too high, it illustrates a worst-case scenario. Since we’re talking about high-temperature cooling, panel temperatures usually do not go below 66°F to maintain set point. So, the panel surface temperature would have to be at 62°F to pull the water vapor out of the air and onto the panel. Homes should be designed around 40-50% RH, which is ideal for health and comfort but also to protect other parts of the building, like exposed wood, artwork, etc. At a target 45% RH, the dew point is 52°F, which is far from any type of condensation scenario.”

This also means these homes do and will require dehumidification, which is being handled by the mechanical system ― not for the risk of condensation on the radiant panels, but to ensure the proper relative humidity for health, comfort, and to protect the homeowner’s assets.

Meeting Sustainability Goals

When it comes to cost, Gutterman said it’s important to look at full cost, not just upfront cost.

“If you're looking at upfront cost, a ground-source system may cost more than an air-source heat pump or a conventional system, but that's only part of the story.”

NET ZERO: The radiant heating and cooling will help achieve sustainability goals through energy efficiency and the reduction of greenhouse gas emissions. (Courtesy of Green Builder Media)

By looking at the whole equation over time, a geothermal heat pump that helps achieve net zero, and results in utility bills becoming basically zero (which is what will be achieved with the Transcend Homes), makes a lot more sense.

While energy reduction is important for achieving a more sustainable built environment, perhaps the biggest impact of the radiant heating and cooling systems is the reduction of greenhouse gas emissions.

“Radiant systems enable higher water temperatures in cooling and lower water temperatures in heating,” Stoko said. “This enables engineers and designers to maximize the efficiency of a heat pump (air-to-water or water-to-water) to satisfy the load conditions in the home or buildings without the need for fossil fuel. Additionally, radiant is a water-based delivery system, which means it can significantly reduce the amount of refrigerant needed. This, in turn, further reduces the impact to the environment against other types of electrification strategies, such as variable-refrigerant alternatives.”

Comfort

Not only will these radiant heating and cooling systems help achieve major sustainability goals, but they achieve major comfort goals as well.

“Radiant is the comfort system that most closely aligns with the human thermal comfort curve,” Stotko said. “People always feel more comfortable with radiant heating at a lower thermostat setting than with forced air at a higher setting; conversely, people are more comfortable with radiant cooling at a higher thermostat setting than with forced air at a lower setting.”

Gutterman can speak from her own personal experience. In her home that sits about 9,000 feet up in the Colorado Rockies, she has radiant heat.

“I love the comfort of radiant heat,” she said. “I really love having my feet warm from that heat coming up from the floor, I love the efficiency of it, and I really love the IAQ element of it.

“What we're trying to do with Transcend is to think about the future of housing and building generational wealth, so that these houses as they get passed from homeowner and the homeowner and generation to generation, they maintain performance, health and wellness, well-being and comfort, and they don't fall apart,” she continued. “By using radiant heating and cooling systems and other advanced products and systems in the home, we're really trying to kind of leapfrog the way that we've been building our homes, which is just no longer adequate.”