Researchers are looking for builders willing to volunteer to take part in a field study that will measure moisture, temperature, and humidity inside high-performance walls in moderate and cold climates.
The Home Innovation Research Labs, a subsidiary of the National Association of Home Builders (NAHB), has put out a call for builders of new homes — additions and remodels aren’t included in the study — who would allow wireless sensors to be installed inside wall cavities. The sensors — as many as ten in a single building — will transmit the data to a remote server.
There are a couple of caveats: walls should have an R-value of at least 20, be relatively airtight, and be located in Climate Zone 4 or higher.
“The results of the study will provide real-life data on long-term performance of walls constructed using energy-efficient practices,” an announcement from the Research Labs said.
It doesn’t cost anything for a builder to participate, and neither builder names nor exact building locations will be included in the final report. Builders can submit multiple homes; monitors will go in this spring and summer with monitoring to continue for at least a year.
Program details and objectives
Research Labs will provide the sensors and related hardware, along with instructions for how to install them. Builders will be responsible for installation, discussing the project with homeowners, and supplying design and construction documentation, such as the results of blower-door testing.
Moisture accumulation in exterior walls is an area of intense interest to building scientists. As buildings become tighter and better insulated, the risk of for long-term moisture damage to sheathing and framing has gone up, particularly in regions with long, cold winters. The topic is the focus of research by public and private labs and has been addressed in many articles and Q&A threads at GBA.
Nay Shah, one of two directors of the project, said that moisture and temperature issues in milder climate zones are much better understood, but there are still plenty of unknowns about high-R walls in cold climates.
“Yes, this has been studied a lot by many people,” he said, “But we do believe there is lots to be learned.”
Of particular interest: what happens inside walls with vapor impermeable layers on both the outside and inside; how ZIP System walls with exterior insulation perform; and which type of rigid insulation applied to the outside of the building (extruded polystyrene, expanded polystyrene, or polyiso) works best.
The number of sensors will vary by the house, but typically would range from five to ten, he said, adding that it was important the sensing equipment be installed before drywall.
“We don’t want to tear into your walls,” he said.
Partial results should be available by next spring, with a full analysis completed by June 2017. Interested builders can apply online at this link.