Show or Hide

Watts Radiant | Floor Heating & Snow Melting

Case Studies

Dave Sellers

Worried About Winter? Or Legionella? Not in this Home.

During his career as an HVAC engineer for high-rise buildings and hydroelectric plants, George Weinshenk knew the importance of hiring the right professionals, and putting quality products and materials into the job. After his retirement, he and his wife Barbara turned their attention to building a new home, one they planned to enjoy for many years to come. The site, 28 acres on a mountain overlooking Lake George in northeastern New York.

The decision to build a log home came quickly. But it took many months of careful planning and the rigorous interviewing of dozens of contractors and suppliers before they were ready to break ground for the 9,000 square foot house. George scrutinized all facets of the process, from foundation and back-up power generation, to heating, plumbing and roofing...and everything in between.

Comfort, indoor air quality and plumbing were high on the list of things to receive special attention. For these needs, the Weinshenk's chose Dave Sellers, David. Sellers Mechanical, based in Warrensburg, NY, to design and install the systems.

Systems, at-a-glance: $100,000 for the mechanicals. Top-of-the-line air filtration; two HRVs; high efficiency, variable speed a/c units; advanced mixing valves for the plumbing system; two Munchkin boilers with outdoor reset controls and 5 miles of Watts Radiant Onix tubing. "I prefer to use Onix for all types of radiant heat applications," said Sellers. "And since we do primarily hydronic heat, with most of that in radiant, we install a lot of the synthetic polymer tubing."

"The Weinshenk's knew they wanted radiant heat," said Sellers. "Fortunately, we're the only firm in the area that's really into radiant, and certainly the only RPA member and RPA-certified designer and installer. We do mostly high-end new construction work, so this job was a good fit."

Sellers got started with radiant heat work in '89 and was quickly introduced to Onix tubing by the manufacturer's rep firm, Emerson Swan. "John Williams was my first contact with the Emerson Swan, and in all these years, he's still there and we've become good friends - he and Emerson Swan are a great resource for me."

"When they introduced us to synthetic polymer tubing, we were jazzed the moment we saw it," recalls Sellers. "For heat transfer, joist bay staple-up - which is what we do most of the time - is the closest thing to plated tubing without the added expense and time," he added. "Since Onix has direct, tight contact with the subfloor, it transfers the heat efficiently, and requires stapling only every eight inches. It works like rope - so we can get it easily into tight spaces, into corners and around angles, going places PEX won't go, and it doesn't have any expansion issues. We can get up to 40 or more BTUs per square foot with Onix if we need it."

Designing for Winter's Worst

"What wasn't entirely typical of the jobs we do was this home's size and its top-of-the-mountain exposure to winter's worst," said Sellers. "With a design temperature of -20°F, we took a few extra precautions when building the Weinshenk's system. The house has 11 zones of heating, including 8 radiant and 3 high temperature zones, plus the indirect- fired water heater. We also installed two separate cooling systems, each with two stage compressors, variable speed blowers, and three zones each. The air filtration is top of the line and includes germicidal UV lights in the air stream. Add to that two large heat recovery ventilators, and we have a very healthy and comfortable whole-house comfort system.

"We wanted a lot of tile flooring," said Weinshenk, "so radiant was the perfect way to warm otherwise cold and uncomfortable surfaces. It also enabled us to heat the home without the need for baseboards. And, in the largest room of the house, it was the perfect solution." The Weinshenk's great room – a 48-foot by 28-foot space with a ceiling peak of 24 feet – was exposed on three sides, including a center wall with many large windows.

"The great room is perfectly suited for entertaining and family gatherings," continued Weinshenk. And it holds its heat well, even in the dead of winter with the winds going full-tilt. Dave solved the need for extra heat along the exterior walls by adding an extra pass of Onix tubing; the technique worked well."

A few Extra Precautions

Being a man of precaution, Weinshenk wanted an "insurance policy" on his radiant heat system. He specified that electric resistance strip heaters be placed in the a/c ductwork throughout the house. "It was for my peace of mind," he said. "But we didn't need them at all. I couldn't say to Dave, 'I told you so!'"

Another of Weinshenk's precautions was the purchase and installation of a 15KW LP gas-powered electrical generator with a V6 engine rated for continuous duty. "To accommodate it, we added a dedicated 100 Amp panel specifically to power essentials within the home during a power outage from the main line. Power is lost up here with some frequency – especially during ice storms or when heavy winds blow branches and trees into the power lines. It's also good to know that the radiant-heated floors act like a thermal storage system, retaining their heat for a long time."

Though radiant heat installations make up 70 percent of Seller's work, his approach to home comfort and energy efficiency stems from a systems philosophy that many facets impact the home's environment and how to calculate, and impact, what they find. As a BPI (Building Performance Institute)-certified contractor, Sellers uses a "whole-house" approach that incorporates comfort, health and safety, durability and energy efficiency into a comprehensive package.

"Buildings are systems of interacting parts," says Sellers. "So our philosophy is to take into account all of the key 'pieces of the puzzle,' and to determine how they affect each other, and what we can do to positively influence what's happening."

Germ Warfare

The "whole systems" approach led Sellers and the Weinshenk's to a mutual decision when the plumbing system was designed. "With such a large home, George knew that he'd need a hot water recirculating system to guarantee that all domestic water sources would have ready hot water," said Sellers.

Speaking with experience from his years in commercial construction, Weinshenk added that, "With hot water recirculation already planned, it was only one additional step to kill the harmful bacteria that invariably grow within the domestic lines. We chose to have Sellers install a whole system, and point-of-use, thermostatic balancing valves."

"There's been a dangerous trend lately to reduce the temperature of hot water within domestic water systems," agreed Sellers. "By lowering water temperatures, legionella and other toxic bacteria multiply quickly, threatening all who come in contact with it. Yet, if water temperatures are set at higher levels to kill the bacteria, the risk of scalding increases."

It's a double-edge sword:

  • Safe water delivery within a home is critical to reduce the threat of scalding and toxic bacteria growth, and...
  • Temperatures within domestic hot water systems – of as high as 180°F – cannot immediately kill "biofilm-insulated" bacteria on contact.

The solution:

Sellers chose to install advanced combination point-of-use under-sink and shower valves (or Type T/P) – a hybrid of both pressure balancing and thermostatic performance requirements. He added one main T/P valve in the mechanical room to govern the whole house. "These valves by Watts Regulator offer the best protection for domestic water use," he said. "Unlike pressure balancing valves that protect only against pressure fluctuations, these combination valves by Watts guard against both pressure and temperature changes."

T/P valves protect the homeowner because they allow hot water to be distributed at higher temperatures throughout the plumbing system, minimizing the occurrence of legionella and other known bacteria while reducing the risk of scalding. The water temperature is then set, and tempered, at the point of use.

"My only disappointment with the job was that the Weinshenk's were passionate about radiant heating before I could start the fire," joked Sellers. "Typically, the homeowners that we work for are knowledgeable about radiant, and interested in it, but not entirely certain that it's the right choice. Actually, I couldn't design a better stage. It's only a short time into my presentation that they see my passion for radiant, grasp of the technology and expertise...and then I get to sell the romance of it. Works (almost) every time."


Northern New York

Radiant Systems Installer

Dave Sellers, Dave Sellers Mechanical


Onix™ tubing

Manufacturer's Representative

John Williams, Emerson Swan

  • Home
  • Solutions
  • Case Studies
Back to top