View methodology by technology/subject: Advanced Framing | Low Impact Landscaping (Xeriscaping) | Permeable Pavement | PEX/Homerun Plumbing Systems | Rainwater Harvesting | Solar Water Heating | Whole-House Energy Consumption | Whole-House Ventilation System
Advanced framing practices will be used throughout the home. A comprehensive analysis and study of the original and final designs will be used to quantify the amount of lumber savings resulting from each specific advanced framing technique. Any additional time spent engineering or seeking code approval for the structure as a result of the use of advanced framing will also be noted.
In the garage, the two gable ends will be constructed using two different details to compare performance. One will be constructed with 2x6 framing and R19 fiberglass insulation, while the other will use 2x4 framing, with 1” of external foam and R13 fiberglass insulation. The internal temperature will be maintained equally for both while the cavity temperature and relative humidity for each will be monitored. Infrared imaging will be used to show the relative thermal performance.
Details about Advanced Framing are available in the PATH Technology Inventory, including manufacturers, and CAD details. The Advanced Framing Techniques TechSpec provides a great overview of this technology.
Fiber-cement siding in a clap-board lapped siding pattern will be used for the majority of siding on the house and garage. Fiber-cement siding is a very durable product made up of recycled cellulose fibers, sand and cement fiber that has been autoclaved (cured with pressurized steam) to increase its strength and dimensional stability. It has the texture and appearance that looks like wood, but should be more durable than wood. It is termite-resistant, water-resistant, non-combustible, and warranted to last 50 years. Planks come in 5¼" to 12" widths and 5/16" and 7/16" thicknesses. Various colors can be surface-applied in the factory or painted on site. Factory-applied paint warranties of up to 25 years are available. However, field-applied paint may need to be repainted every five years. Installation, cutting, and fastening of fiber-cement siding will be observed and filmed for educational purposes.
Details about Fiber Cement Siding are available in the PATH Technology Inventory, which includes resources and manufacturers.
Fly Ash Concrete
Fly ash will be used as a partial substitute for portland cement in concrete used to fill the insulating concrete forms (ICF) for foundation walls. Fly ash is a waste material recovered from coal-fired power plants that produce millions of tons of fly ash annually, which is usually dumped in landfills. Fly ash is an inexpensive replacement for portland cement, while it actually improves strength, segregation, and ease of pumping of concrete. When fly ash is mixed with lime and water it forms a compound similar to portland cement. Information will be collected on the cost of fly ash concrete as compared to conventional concrete.
Details about Fly Ash Concrete are available in the PATH Technology Inventory, which includes resources and manufacturers.
Insulating Concrete Forms (ICF)
Insulating concrete forms (ICFs) are rigid plastic foam forms that hold concrete in place during curing, and remain in place afterwards to serve as thermal insulation for concrete walls. The foam sections are lightweight and result in energy-efficient, durable construction. ICFs consist of insulating foam, commonly expanded polystyrene (EPS) or extruded polystyrene (XPS). ICFs will be used to form structural reinforced concrete foundation walls for the house. They also provide backing for a future interior finish that can be fastened to plastic inserts. Cost information will be collected, and erection of ICF blocks and installation of concrete pumped into ICF walls will be observed and filmed for educational purposes.
Details about Insulating Concrete Forms (ICF) are available in the PATH Technology Inventory, including manufacturers, and CAD details.
Low Impact Landscaping (Xeriscaping)
Project staff will work with appropriate partner organizations and the school’s landscaping instructor to identify drought-tolerant grasses and trees. Several grass test plots will be created to study the ability of different grass mixes and species to tolerate various levels and types of watering scenarios appropriate for the area. The condition of the grasses will be assessed visually. The goal is to determine the grass type requiring the least irrigation, while minimizing required cutting.
Details about Xeriscaping are available in the PATH Technology Inventory, which includes resources and examples.
The pervious concrete driveway of the home will be evaluated for installation costs and issues, relative to traditional pavement. Data will again be used from the weather station to determine the amount of precipitation that has fallen onto the pavement. Flow sensors will monitor the amount of water permeating through the pavement to derive capture efficiency. Analyses will examine whether the efficiency is maintained over time, and through winter seasons. Placement of the stone subbase and pervious concrete will be filmed for educational purposes.
Details about Permeable Pavement are available in the PATH Technology Inventory, including manufacturers, and CAD details.
PEX/Homerun Plumbing Systems
PEX (cross-linked polyethylene) plumbing systems have been studied in a number of different PATH project homes in the past. The installation of PEX will be used primarily for educational purposes in this project. However, it will also be used to demonstrate energy and water savings potential from use of smaller diameter piping to the outlets. In addition, the energy savings potential from use of distributed water heaters and a solar pre-heat system will also be evaluated. The use of a PEX manifold system will also include evaluation of a rainwater system to supply non-potable water to outlets such as toilets.
Details about Cross-Linked Polyethylene (PEX) Piping are available in the PATH Technology Inventory, including manufacturers and many resources. The Home Run Plumbing Systems TechSpec provides a great overview of this technology.
In addition to collecting installation cost and process information, the integrated rainwater collection system will be monitored using a variety of sensors. The system will be integrated into the home such that rainwater can be used to supply water for toilet flushing, exterior hoses, and washing machines. Performance will be monitored by using a weather station to estimate the quantity of rain falling on the roof, and measuring the actual input into the collection system to gage capture efficiency. The volume of water utilized will be measured when the home is occupied and, along with water cost information, used to calculate the system payback period. Finally, the quality of the water in the rainwater cistern will be monitored by measuring bacteria count and type. Since the home will not be occupied for a period of time, water usage will be simulated. Monitoring will continue after the home is occupied.
Details about Rainwater Harvesting are available in the PATH Technology Inventory, including manufacturers, and CAD details.
Solar Water Heating
A solar water heating system will be used in tandem with a tankless water heater to supply all domestic hot water. The installation process and costs will be monitored, as with the other technologies. While occupied, the thermal output of the system will be measured by monitoring water flowrate and the temperature change of the water across the unit. A pyrometer on a weather station will quantify the amount of solar resource at the site for comparison with other locations being monitored in the country. Ultimately, monthly energy savings and the economic payback will be calculated for the system.
Details about Solar Water Heaters and Tankless Water Heaters are available in the PATH Technology Inventory.
Sprayed Cellulose Insulation
A sprayed cellulose system, in which cellulose insulation is sprayed into wall cavities while slightly damp (to promote adhesion) will be used. Spray cellulose completely fills wall cavities, permitting full coverage and full insulation levels around obstructions (such as electrical outlets) that often cause compression, and R-value reduction, in batt insulation products. Cost information will be collected for comparison to fiberglass batt insulation, and the spraying and finishing operations will be observed and filmed for educational purposes.
Details about Sprayed Cellulose Insulation are available in the PATH Technology Inventory, including manufacturers, and CAD details.
Tubular skylights will be installed in a second floor windowless closet and hallway ceiling to light the interior space. Tubular skylights are generally easier to install than typical skylights and, from the home's interior, resemble conventional lighting fixtures. Tubular skylights have a roof-mounted light collector typically consisting of an acrylic lens set in a metal frame. Most have a reflective sun scoop in the rooftop assembly that directs sunlight into a metal or plastic tube which has a highly reflective interior coating. The reflective tube guides the sunlight to a diffuser lens, mounted on the interior ceiling surface, which spreads light evenly throughout the room. Cost data will be collected, and installation procedures will observed and filmed for educational purposes.
Details about Tubular Skylights are available in the PATH Technology Inventory, including manufacturers, and CAD details.
Whole-House Energy Consumption
The energy consumption of the home as a whole will be measured for comparison purposes with other green and energy efficient homes. Testing planned includes: collection of whole-house energy use utility data, blower door testing, duct blaster testing, and infrared camera imaging. Lighting circuits will also be monitored separately to quantify the savings resulting from the use of compact fluorescent lights, and their payback in this project.
Whole-House Ventilation System
The whole-house ventilation system will be used to introduce fresh air in to the home. Monitoring of the system will be conducted to determine the flowrate and temperature of the ventilation air. This will be used to calculate the additional heating and cooling loads imposed on the home as a result of the ventilation system.
Details about Whole House Ventilation Systems are available in the PATH Technology Inventory, including manufacturers. The Whole-House Ventilation Systems TechSpec provides a great overview of this technology.