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Collaboration: Monitoring Performance & Building Research

Performance monitoring and research into building materials and techniques is an ongoing part of the The Affordable Natural House project. We will be updating this page from time to time to describe these techniques and our results. The monitoring and research includes:

• Determining how effective the design of the passive cooling system is in reducing summer heat gain into the house.
• Quantifying how much the insulated shutters reduce the winter heating bills
• Measuring the effect of the passive solar design and substantial thermal mass on overall house performance.
• Discovering how long the straw-clay walls take to thoroughly dry in Wisconsin's climate.

Click here to see the straw-clay thermal performance test results by the U.S. Forest Products Laboratory.

Temperature and moisture sensors for many points in walls, floors and ceilings were installed for ongoing monitoring. This effort is a field research project of the Madison Area Technical College, with generous help from Computer Electronics Program Director Terry O'Laughlin, P.E.



Temperature sensors
Anthony installs temperature sensors before the earthen floor slab is laid down. We're using precision integrated-circuit sensors, LM34 from National Semiconductor, soldered to teflon-sheathed shielded cable, and double-sealed to keep out moisture. We tested the assemblies before and after the installation with a Fluke 8010M multi-meter. These accurate, low-cost sensors have output voltage that is linearly proportional to Fahrenheit temperature, which makes for convenient direct reading.

Moisture sensors
Sixteen plugs cut from a single piece of Douglas Fir timber will function as moisture sensors. We place them inside the walls, in direct contact with the straw-clay.

left: Sequence of fabrication....
The small brass screws are spaced the same distance apart as the probes of our Delmhost BD-10 moisture meter. The wires allow for accurate remote readings of the plugs deep in a wall. After soldering, the connections are thoroughly covered with an insulating coating to prevent a false reading.

Since the meter is calibrated for Douglas Fir, we're able to monitor comparative moisture levels, and gain insight as to how moisture moves through the walls.

This diagram shows sensor locations in the air core floor. Temperature at each location is measured at three depths: within the earthen slab itself, the air moving within the core, and several inches down into the gravel sub-base.

Other collaborators:
• We are working with Minnesota scientist Douglas Piltingsrud to develop better practical ways to formulate and test clay mixes for wall plasters and earthen floors.

• University of Wisconsin Senior Scientist Dr. Wes Jarrell (and president of Dynambio, LLC) is helping to design and develop an innovative indoor plant-growth system

• Spark Burmaster, E.E., BBEI, of Home Environmental Options is consulting on the low-EMF electrical system (healthy wiring).

• Advice on monitoring techniques and experimental protocols are being kindly provided by Anton Ten Volde, PhD, Research Physicist, and Bob Munson of the Forest Products Laboratory in Madison, Wisconsin; and, James S. Elleson, P.E., Director of Technical Services at the University of Wisconsin's Heating, Ventilation, Air-Conditioning and Refrigeration Center.

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Design concepts | Site | Workshop | In-progress | House Detail | Research | Interview w/ Lou