In this segment, host Paul Ryan visits the residence of Alvin Sain -- a home that, because of its design, is one of the most energy-efficient homes anywhere in the US. The 2000-square-foot house on the outskirts of Pittsburgh was built in the year 2000, and its creation was based on an attempt to push the envelope on energy-efficient design. Before he began building the house, Sain worked as a professional engineer and learned about a lot of new technologies designed to enhance home energy-efficiency. He decided that he wanted to build a house that utilized as many of those technologies as possible. He began work planning and building a house following a list of guiding principles and design constraints including: - Making the house energy efficient
- Making the house healthy and safe
- Meeting all of the requirements of the American Lung Association for a health-house
- Using earth-friendly materials
- Keeping the costs below $200,000
- Completing the project within the span of 15 months
- Meeting all local building codes
- Make the house easy to maintain and a joy to live in (more livable)
Foundation, Exterior Shell and Windows The quality of the thermal shell began with the foundation and basement wall using insulated concrete forms (ICFs) for a high-mass wall with an R-value of 20. The forms consist two outside layers of foam held apart by plastic ties. The concrete was poured directly into the forms (figure A). This system allowed the owner to construct the forms himself and get the assistance of a crew for pouring. The resulting wall is thermally sound and provides a nice structure that is easy to waterproof. The roof and walls were constructed using structural insulated panels (SIPs) ( figure B) manufactured by R-Control B.. The panels have foam centers and arrived at the building site cut and ready for assembly. The wall sections are simply fastened to 2x6 base plates with staples. The roof assembly is similarly straightforward, with large screws securing the roof to the walls. The foam centers serve the same purpose as fiberglass insulation in a standard house. R-values for the roof and walls are R-23 and R-38, respectively and the joints are sealed with a patented product combining glue and flexible sealant. The windows and doors are aluminum-clad wood framed with high-performance double glazing. The double-glazed windows (figure C) are argon-filled, and are highly energy-efficient. The french doors have a special lock which not only provides the security of a deadbolt, but also pulls the door tighter against the seal.
Heating, Cooling and Ventilation The house is heated with radiant-floor heating using a VoyagerB. high-efficiency gas water-heater (figure D). The water-heater has a 45-gallon capacity and is rated at 100,000 BTUs. It is quite efficient at converting gas to heat, with a recovery efficiency of 94 percent and an annual energy factor (AEF) of 86. This unit will provide all of the heat for the house and the hot water needs of the occupants under almost any condition. The house is divided into five heating zones: living room, master bedroom, basement, garage (radiant floor), and remaining rooms. The heating system uses a single pump to direct water into separate tubes (figure E), each dedicated to a particular zone. During construction of the house, the tubing was laid out in the floor and concrete poured over it. Hot water flowing through the embedded tubes heats the entire floor. This type of radiant heat is not only efficient, it is considered to be more comfortable than hot-air heat -- allowing the thermostat to be set back while the house is still kept comfortably warm. The separate zones allow the heating of the house to be fine-tuned to further save energy. The air-conditioning system is a split system consisting of an air-handling unit (AHU) located in the center of the upstairs and an A/C unit located outside the house. The outdoor unit cools a refrigerant and pumps it into the house, into the cooling coil located below the AHU. Return-air from the rooms is circulated down through the coil where it is cooled and distributed to the house. The ducts and AHU were sized to match the 2-ton A/C unit. All duct seams were sealed with foil tape and all flex connections and metal duct seams were sealed with mastic. The system achieved very low leakage rates and highly efficient flow rates. Since the actual efficiency on A/C units is typically low at the beginning of a cycle and levels off later, correct sizing will extend the running time each cycle, improving the efficiency. The Lifebreath B. clean air furnace combines the air handling unit and heat recovery ventilator (HRV) in one unit. The HRV (figure E) brings in fresh air from outside and exhausts the same amount of stale air from inside. Building an airtight house can create problems with stale air -- which is why the house is equipped with a heat recovery ventilator (HRV) unit. If fresh outside air were introduced directly into the air-handling system, it would be uncomfortable. This HRV (figure F) tempers the air brought into the system from the outside -- warming it in the winter, and cooling it in the summer. It does this by transferring heat from the outgoing air stream to the incoming fresh air. Heat is exchanged at a rate of 67 percent. A hot water coil tied to the radiant heating system provides the necessary heat, eliminating the need for an additional combustion source. With this system, the fresh air that ends up in the house is always at a nice, even temperature. All of the systems shown in this segment were all professionally installed on this house during the construction process. According to Alvin, however, the same or similar systems could also be incorporated into a home addition or major re-model of an existing house.
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IBACOS
Ibacos
Pittsburgh, PA 15222
Phone: 412-765-3664
Website: www.ibacos.com
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