Residential Issue: Puget Sound, Washington
Radiant Architecture Fall 2011
Whether a given project is a certified LEED home or merely one that strives to emphasize green building concepts, the holy grail of the green building movement has been to approach as closely as possible to a “net zero” impact on the country’s energy supply.
Donna and Riley Shirey’s “Zero Energy Idea House” in Bellevue, WA, is an elegant solution to the challenge of creating an attractive and comfortable home that, over the course of a year, feeds about as much energy into the power grid as it draws from it. Any well designed and installed radiant floor heating system will deliver some efficiencies as compared to forced air. But when highest efficiency is important, Warmboard has become the go to radiant technology. Clinkston Brunner Architects utilized a variety of innovations to help the Shirey's reach their net zero goals. In the process they produced a striking lakeside home that is as comfortable as a pair of well-worn shoes.
The 1,630-square-foot, two-bedroom Zero Energy Idea House was designed to demonstrate that smart choices will result in a home that minimizes energy use while maximizing comfort and style. In the case of the Zero Energy Idea House, rooftop photovoltaic panels and a vertical axis wind turbine meet the home’s electrical needs. Evacuated tube solar collectors, in combination with an air to water heat pump, supply both the home’s domestic hot water needs, as well as the warm water circulating in their Warmboard radiant floor system. In addition to incorporating on site renewable energy sources as well as highly efficient heating, appliances, lighting, and windows, the Zero Energy Idea House’s structure itself makes a major contribution to meeting the project’s energy goals. Though the cooling loads are not great in the Puget Sound area, any solar gain that might otherwise over heat the home in the summer is mitigated by a vegetated “green” roof, which also reduces storm water runoff. The house was built with structural insulated panels (SIPs). SIPs are polystyrene panels that combine framing, insulation and exterior sheathing in one system that can be used for roofing, walls or floors over crawl spaces. SIPs are custom-manufactured from project drawings, and although they are a little more expensive than typical framing materials, they save considerable time, labor and waste on the jobsite and result in a structure that is tightly built and extremely well insulated.
Architect: Clinkston Brunner Architects
Clinkston Brunner Architects [CBA], in Seattle, WA, has extensive leadership experience on a broad spectrum of award-winning buildings throughout the Puget Sound region. Sustainable practice is at the core of their firm. As principal architect for the Zero Energy Idea House, Clinkston Brunner led the design process with a goal of fully integrating sustainable systems and features with the architectural design. As a demonstration project, it was important that the building largely “explains itself” to the public at first sight, without need for further description. Lead designer David Clinkston describes the aesthetic approach to the project, as “what you see, is what you get”. As people drive by on West Lake Sammamish Parkway, the photovoltaic panels, evacuated tube solar collectors, vegetated roofs, and a windmill immediately identify this as an advanced technology green home. "At CBA, we like using radiant due to improved air quality, the high comfort level for the homeowner and because we don't have to accommodate duct work in our designs. What we like about Warmboard, specifically, is that it's a highly efficient system, especially in comparison with other radiant systems: heat is delivered by the thick aluminum plate on the top side of the floor, which provides highly effective and even distribution, with the result that the required water temperature to operate the system is lower than is the case with other systems. Because Warmboard is the subfloor, it's really quite easy to incorporate into our designs as well. We've also found it to be the best radiant product for zoning different areas of the home so that homeowners can choose just where and when they want heat provided. When the builders/homeowners Donna and Riley Shirey brought the idea of the 'Zero Energy Idea House' to us, we were immediately drawn to the concept of designing a demonstration deep green home with a goal of energy independence. For us, Warmboard was just the perfect product to use for our radiant system. It was the most efficient, simply superior, and it really integrated well with our design and the natural wood floor finishes." David Clinkston
Clinkston Brunner Architects 105 W John Street Seattle, WA 98119 www.clinkstonbrunner.com/
Builder/Homeowners: Shirey Contracting, Donna and Riley Shirey
Located in Issaquah, WA [a suburb of Seattle], Shirey Contracting has won many awards for their renovation/remodel projects as well their many fine custom new homes. They provide creative design-build solutions for projects of all sizes. Since 1982 they’ve maintained a consistently successful business model. This model has always relied on listening carefully to their clients and creating innovative solutions based on their individual needs, desires and budgets. They are industry leaders in Built Green construction and specialize in the use of Structural Insulated Panels (SIPs). "From concept to completion, the Zero Energy Idea House took four years to build. Because the technologies we used had never really been done before in our area, we had a few extra hoops to jump through regarding special plans review for the wind turbine and solar voltaic systems. The city of Bellevue was great, however, through the entire process. It was a learning experience for them and others and we hope more homeowners, builders and architects in our region will incorporate more renewable, self-sustaining energy systems into their custom home projects. The end result of that extra time was well worth it. We have an amazingly beautiful home that's virtually 100% self-sustaining. I recall our last electricity bill as being something close to $7.00! We used Warmboard precisely because it's the subfloor - putting in the subfloor and heating system all with one product and process saved in costs and other resources. Warmboard also worked well with our flooring choices: tile and then the hickory veneer atop an engineered substrate. As the homeowners, we really enjoy the comfort of Warmboard and also how we were able to include separate heat zones. We can heat the rooms which we're using and increase our efficiency. Also, due to Warmboard's low mass and aluminum-clad panels, bringing a zone or room up to heat is fairly quick." Donna Shirey Shirey Contracting, Inc. 230 NE Juniper St. Issaquah, WA 98027 www.shireycontracting.com
Understanding Radiant Technology
From Terry Alsberg Warmboard’s inventor
Given the theme of the Shirey’s home, I was expecting to focus my comments this month on the thermodynamics of energy efficiency. But when I asked Donna Shirey what most motivated her to choose radiant I was a little surprised but not shocked when she told me it was the even, comfortable quality of heat that radiant provided, more than its energy efficiency. I wasn’t shocked because all studies of our industry tell us that the radiant benefit most important to home owners is superior comfort, even though radiant systems can be as much as 40% more energy efficient than forced air heating.
What thermodynamic principles cause radiant’s even warmth and therefore its comfort? In simplified terms, the Second Law of Thermodynamics (also sometimes called the Law of Entropy) tells us that heat moves from hotter areas to cooler areas until it’s evenly distributed. If your home were perfectly insulated, given enough time, the 140˚ air that pours out of a forced air register in a room would move to cooler areas and eventually you might get a perfectly even distribution throughout that space of about 70˚. If it reaches this ideal, a thermodynamicist would call this a more Entropic condition then if were hot in one part of the room and cool in another.
But it’s impossible to perfectly insulate a home, which means that heat constantly flows out through your walls, floors and ceilings causing heat loss, which must constantly be balanced by the hot air supplied from the forced air register. As fast as heated air piles up on one side of a room or near the ceiling (because hot air rises), heat is flowing out of other parts of that room due to heat loss, so the heat will always be relatively uneven (less Entropic).
Radiant begins as an inherently better distributed means of supplying heat. Instead of a small register spewing hot air on one side of a room, every square inch of your floors are evenly warmed to a very mild temperature, typically between 75˚ and 80˚, keeping your toes, children and pets nice and cozy. And because the air layer in contact with that floor is only warmed to a few degrees above the 70˚ you may have set at your thermostat, it does not rapidly rise like the overheated air from a forced air register, which tends to stratify near your ceiling. Instead, it tends to drift slowly up through cooler air layers bringing them to your ideal temperature setting. Radiant naturally tends to reach the evenly distributed condition that satisfies the Second Law of Thermodynamics at the same time that it satisfies your need to be comfortable. So if you have guests over who notice the even comfort of your radiant floor heated home, you can tell them, “ Oh that’s just because we have a more Entropic heating system.”
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