Radiant Defends Homestead Against Winter
October 6, 2008
Tim and Wendy Brockish’s back-to-nature homestead had one key flaw. There in Rexburg, Idaho, in the Snake River plain just to the west of the Rocky Mountains, Mother Nature takes off the kid gloves during the long winter season, generously doling out heavy snowfalls and brutally cold temperatures. It’s enough to send newcomers to the area packing hastily for the next flight to Miami. Yet the Brockish’s elegantly rustic home is near the joining of two creeks, forming a slough visited year-round by wildlife, including mule deer, coyote, trumpeter swans, eagles, beaver, and an occasional moose.
The Brockish’s roots in Idaho go back to the mid-80s, so they weren’t about to give up their dream of an idyllic home on the range. Tim grew up in Colorado, and Wendy in Wisconsin. No strangers to winter conditions, they decided early on to make a go of it. “We’ve never regretted it,” said Wendy.
Thanks to geothermal HVAC and radiant heat, Tim and Wendy now look forward to each new winter season.
MICE LIKE IT TOOWhen they bought the property in 1994, an old double-wide served as home for several years. “We purchased eight acres and worked on the property steadily,” said Tim. “At night, we heard the sound of mice in the walls, so we weren’t the only ones enjoying the location.”
Tim explained that, in 2000, they purchased an adjacent 70-acre farm planned as an annex to their now-extensive water life rehabilitation effort. At about the same time, they removed the trailer and began construction of the home they now live in. Initially, the house had an electric furnace and pellet stove as the heat sources.
“We had sufficient space to have some 6-foot-deep trenches dug for slinky-loop geoexchange, so in 2002 we did that and upgraded the HVAC system to a ClimateMaster geothermal unit for heating and cooling,” said Tim. “We saw a big reduction in our energy bills, and the geothermal system has done well for us over the years, especially in the summertime. The system has added tremendously to the level of comfort we have at home. The only drawback to the forced-air system was that we still had cold floors. That’s what fueled our interest in radiant.”
For months, Wendy researched radiant heat so that they could make informed decisions about how to specify the type of system they would want for their 2,200-square-foot two-bedroom home.
Tim explained that groundwater at their property is reached at a depth of only 8 feet, so that eliminated the possibility of a radiantly heated basement. The house is constructed above a 3-foot crawl space. So it was in this area that Justin Johnson, owner of Idaho Falls, Idaho-based Sprinter Heating and Hydronics, and Todd Hamilton, senior technician, went to work last year to install a radiant heat system to serve as the home’s new primary heat source.
Connected to the network of staple-up radiant heat tubing are mechanical systems they installed in a water heater closet, including a high-efficiency, LP gas-fired condensing boiler and a wall-hung, tankless water heater. The space was vacated by an 80-gallon electric water heater removed by Johnson and Hamilton. Johnson designed and built a control panel using a simple microprocessor control and several Grundfos, multispeed circulators. Nearby are the manifolds that supply the heat to the three-zone, eight-loop distribution system.
MULTISPEED CIRCULATIONOne of the most important facets to optimal circulation for hydronic systems is for contractors to match a pump’s performance, or flow characteristics, to the specific job that it needs to perform within the system. A single-speed pump has one performance curve - a measurement of head (feet) and flow (gallons per minute) - and operates at that level only.
“But with the Grundfos SuperBrutes, we get a much broader range of performance,” said Hamilton. “With the flick of a switch, various speeds can be chosen, easily changing head and flow to meet the specific needs of the system. Soon, we’ve heard, they’ll have variable-speed circs, too - just what the doctor ordered.”
Three temperature zones were required because of the dissimilarity of the floor coverings on the first floor which includes hardwood, vinyl, and wall-to-wall carpet. By using RadiantWorks, Watts Radiant’s system design software, the varying floor supply water temperatures were quickly matched with manifolds, loop lengths, and flow rates.
The system that Johnson designed would call for multiple temperatures from a single temperature source. “The Brockishes had set a fairly tight budget for the project, so I settled on a simple mixing strategy,” said Johnson. “A simpler-is-better approach not only saves money on the front end by reducing installation and material costs, electrical costs are minimized, too. This is often ignored when systems are designed. A primary loop drives the heated water past two detours. If a heating cycle is activated, Btus are diverted to a three-way mixing valve which then tempers the water, as needed.”
About 2,200 lineal feet of Watts Radiant EPDM Onix tubing was installed by Johnson for the home’s staple-up radiant system, chosen because of the several advantages it offered. “We like the material because of its excellent heat transfer when stapled up,” said Johnson. “The tubing, by design, is slightly flattened against the underfloor when stapled into position. This greatly increases the surface area for contact with subfloor, moving heat out of the tubing and into the floor - without metal plates.”
“And, because of its flexibility, we spend a lot less time on the installation - unlike PEX which has a mind of its own,” added Hamilton. “Plus, we couldn’t have used PEX. Onix was the only tubing we could use to weave between the thousands of protruding metal nails driven through the subfloor when the home’s hardwood flooring was applied.”
CALLBACK!Johnson and Hamilton completed their radiant heat system work on a Friday. But by Friday night, Tim knew that something was wrong. One of the three zone pumps was warm while the other two were toasty hot. Same for the three lines of tubing they fed. So he called Johnson, who promised to be over the very next day.
“True to his word, by early Saturday afternoon Justin had it all sorted out,” said Wendy. It turned out that a couple of wires were crossed; the bedroom and bathroom thermostats had each been sensing the other’s assigned zone. As soon as Justin rewired them correctly, the bathroom began to warm. And by Sunday morning Wendy described it like this, “Yippee! Master bathroom bliss!”
It took only a week for Johnson and Hamilton to install the Brockish’s new heating system. But the response last winter was immediate. Wendy was effervescent.
“We’re loving radiant heat,” she exclaimed. “I noticed an amazing thing last winter: At the end of the work day, I find my thoughts quickly turn to the happiness I’ll feel when I arrive home and open the door to a cozy, warm, comfortable house. As proof of the value of this stuff, our ol ’ arthritic dog Luke [age 12], now lies sprawled on the warm floor, instead of balled up in his cozy crate, clearly soaking it up in great contentment. He sure seems pleased.
“Tim and I are as thrilled as can be. We can’t believe what immediate satisfaction there is in radiant. For me in particular, it’s a special boon. A couple of years ago I developed an auto-immune connective tissue problem. Last winter I was miserable. I wasn’t sure how I’d survive another winter season. Since the house has been warmed by radiant, I look forward to the beauty, and comfort, of each new winter.”
Publication date: 10/06/2008