But we have so far to go. I can remember the days when R13 was over the top in terms of insulation. Nobody would ever need that much. Now we are are encouraging R60 in the attic. But we have so far to go. Don’t get me started on other parts of the world. There is no way we can supply decent housing to 7 billion people, but they will all want televisions.
House of Pressure
by Anthony Cox and Melissa Byrd
A Model of Energy Efficiency
The New River Center for Energy Research and Training (NRCERT) in Christiansburg, Virginia, is a division of Community Housing Partners (CHP), a nonprofit development corporation that serves the needs of low-wealth and low-income residents in the Southeast. NRCERT was established in 1999 to provide training to emerging professionals in the fields of in weatherization and whole-house performance skills. NRCERT also performs research for leaders in the field. This research has resulted in significant technical advancements for the weatherization and building performance industries.
NRCERT’s training emphasizes a whole-house approach to home performance, using detailed curricula and innovative models to support these training efforts. Its goal is to create homes (both new construction and retrofit) that are good for people, good for the environment, and good for business. Technicians are taught to reduce energy consumption, address the health and safety of occupants, and assess how the building envelope, appliances, and occupants interact with one another.
One of the teaching tools is the House of Pressure, which Anthony designed in 1995 for himself. He designed this tool to help visually demonstrate to his peers the complicated science of air pressure. At the time, Anthony was a weatherization crew member with New River Community Action.
The House of Pressure visually demonstrates pressure and air flow dynamics within a residence, using pressure diagnostics. It is a model of a single-family home, made of a clear, high-strength plastic laminate called Lexan that can be written on with a dry-erase marker. The interior of the House can be viewed from all four sides. It gives the instructor the ability to create and control air flow with working scale reproductions of the mechanical air distribution systems that are found in most homes.
The House features an operable forced air duct system, a clothes dryer, a bathroom fan, a fireplace, and a water heater. There are smoke generators in the water heater and the fireplace to demonstrate the dangers of backdrafting; and a smoke generator in an exhaust pipe in the garage to show the danger of CO infiltration from a garage into conditioned space. (The menacing theme of Jaws plays when backdrafting occurs, as a warning that smoke is coming back into the House!)
An automated performance testing (APT) device from the Energy Conservatory measures the air pressure levels in eight different locations in the House. It uses Microsoft Excel to project those pressure levels onto an LCD screen, so that audiences can view the pressure levels and the direction of air flow in every room. It’s like having eight manometers going at the same time, so when you make changes to one part of the House, you can see how they affect every other part, with immediate feedback from the APT.
Testing the Model Is the Same as Testing a Real House
To get accurate results, it’s important to understand how to set up and use diagnostic equipment—and the House of Pressure is no exception. An illustrated laminated sheet with instructions comes along with the model. The instructions show how to set up the measuring equipment to perform various tests on the model, and also how to use the equipment in the field. It even has color-coded hose hookups for using the digital manometer.
The House of Pressure can be used to
- demonstrate blower door testing, using a digital manometer and a Minneapolis Duct Blaster;
- demonstrate zonal and pressure pan testing;
- show how duct leakage diminishes health and safety, comfort, durability, and energy efficiency by creating leaks in the supply ducts and/or the return ducts;
- demonstrate the effect of thermal bypasses;
- show pressure and thermal boundaries; and
- simulate backdrafting conditions.
There are operable doors from the bedroom and bathroom to the central living area that show how air flow takes place in a house with a central return duct system. Pressure relief methods can be shown and discussed. Combustion appliance zone testing can be shown by following a worst-case test procedure using a digital manometer.
Please read the magazine every month…as Yoda says…do not try…do