Researching a Quality Home®

To further our mission of enabling the industry to build quality homes, IBACOS (Integrated Building and Construction Solutions) is constantly looking for opportunities to research, evaluate, and test new systems and methods used to design and build homes to higher levels of performance. While these opportunities arise with production homebuilders from time to time, cost and time constraints often prevent them from exploring innovative design and construction strategies. In 2002 and 2003, IBACOS had the opportunity to take a home “off line” and dig into the practices necessary to design and build to extremely high levels of performance—in terms of occupant safety, health, and comfort, as well as building durability and efficiency.

In addition to testing new design and construction strategies to achieve Building America levels of energy performance, IBACOS is using this home, located in the cold climate of Pittsburgh’s northern suburbs, to educate consumers. The goal is to illustrate to consumers the key areas of construction where quality and performance decisions are made, using best practices based on IBACOS’ research. The construction process was filmed and documented for a cable television series by The Do It Yourself (DIY) Network. The series will air in a 26-part series called “Home IQ” in early 2004 that focuses on the design and construction process of a high performance home.

Advanced Building Systems The 3,074 square foot home (basement is an additional 2,911 square feet) was designed to be at least 50% more energy efficient than typical houses. The final performance result was a Home Energy Rating System (HERS) score of 91.4, a reduction of more than 55% in energy use beyond the 1993 Model Energy Code (MEC) benchmark. The home was also designed to be comfortable, durable, safe, and healthy.

The home was recently occupied, and IBACOS is monitoring the performance of some of the advanced building systems to further our research into quality homes.

Improved Building Enclosure

Homes stay warm in winter much like people do: both need heavy clothes covering all their exposed parts. Insulation, a home’s clothes, should be placed in all areas that face the elements—including the foundation, exterior walls, and in the roof area. (These three areas are called the building enclosure.) Not having insulation in one of these areas is similar to wearing a coat but no gloves. The building enclosure also needs to be well-sealed so that air doesn’t leak in or out, which is like having your coat open on a cold day. To make the Demonstration Home efficient and comfortable, IBACOS used increased insulation in the foundation (R-10 rigid fiberglass on the exterior, R-5 extruded foam boards on the interior), the above-grade walls (3 ½ inches of spray foam insulation supplemented with 1 inch of R-5 rigid extruded polystyrene sheathing, for a total insulating R-value of 19.3), and the roof (9 ½ inches of R-34.2 spray foam insulation applied to the underside of the roof sheathing in the unvented attic). In unvented attics, insulation is placed between roof rafters rather than on top of the ceiling.

In addition to providing excellent insulation, spray foam also increases the airtightness of the building. This helps to reduce airflow moving into and out of the building, a reduction that further improves the overall energy performance and comfort of the home.

That leaves one unprotected area—the windows. Chances are you’ve heard complaints from homeowners about drafts around windows, or that they are too cold (or hot) to stand near. IBACOS used low-emissivity, argon-filled, airtight, windows (U-0.32, SHGC-0.33). These windows reduce the amount of cold air that can enter the home through the windows in the winter, reduce the amount of heat loss through the window when the house is being heated, and reduce the amount of heat that can enter in the summer. With the windows helping to keep out outdoor air, homeowners won’t have to turn up the furnace or air-conditioner, which again saves energy.

High-Efficiency Mechanical Systems

Bundling up a house against the elements has an additional benefit: it reduces the home’s heating and cooling requirements. This means you can specify smaller sized (capacity) mechanical equipment, which is less expensive. High efficiency equipment will reduce operating costs, something homeowners will love, since they use less fuel or electricity to do their work.

In the Demonstration Home, a high efficiency single heating and cooling system serves two zones: the second floor is one zone, and the first floor and basement is the other. This zoning allows homeowners to control the temperature so that energy isn’t wasted heating one floor that’s not in use. Space heating is provided by a gas furnace (annual fuel use efficiency, or AFUE, is 96.6), and cooling is provided by a high-efficiency air-conditioning unit (seasonal energy efficiency ratio, or SEER, is 14). The equipment was sized using accurate engineering design methods to optimize the performance of the equipment. The result is that the air-conditioning system serves 945 square foot of floor area with one ton of cooling. This ratio is high relative to the conventional “rule of thumb” in the Pittsburgh region (500 to 600 square feet served by one ton of cooling).

Forced Air Distribution System

An efficient mechanical system doesn’t matter much if the heated or cooled air it generates doesn’t get to the rooms as designed. The distribution system in this home is made up of ducts fabricated from both fiber glass duct board and galvanized sheet metal. Wall or floor joist cavities were not used to carry air. We designed the system for how much airflow was needed in each room, and then sealed all ducts with UL-181 approved mastic, which minimizes the amount of air that can escape through the joints in the ducts before being delivered to the rooms. In addition, we located all the ducts within heated or cooled space, so that air flowing through the system will be delivered to rooms at the temperature it was meant to.

Mechanical Ventilation

While a well-sealed home is efficient, sealing the home so well that odors and excess moisture can’t escape can lead to poor indoor air quality. Mechanical ventilation is essential in well-sealed homes.

An energy recovery ventilator (ERV) was installed in the Demonstration Home to provide fresh outside air to the occupants and exhaust stale indoor air at the same rate. This ventilation also helps to reduce indoor moisture accumulation. The controls for the ERV are separate from the heating and cooling system, allowing the fan in the ERV to run continuously. Switches in the bathrooms put the ERV fan into high speed, allowing the ventilation rate to be doubled on demand to reduce moisture.

Efficient Appliances and Lighting

High efficiency, Energy Star® compliant laundry appliances, a water-saving dishwasher, and an efficient refrigerator provide savings in both water and energy. Fluorescent lighting contributes to reduced energy use and dramatic enhancements of the architectural character of the home. The advanced lighting system features:

1. Wayfinding to illuminate principle pathways at low levels, saving energy.
2. Ambient layer of lighting that provides overall illumination while dramatically featuring high spaces, cabinetry, and wood finishes.
3. Task lighting to apply to areas and activities when needed.

The IBACOS Demonstration Home is a unique opportunity to showcase the process of integrating systems to achieve a high performance home to a national audience through cable television.

In addition, this project also demonstrates that a large home with many amenities can achieve a high level of energy performance, which enhances its customer satisfaction.