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Moisture Performance Monitoring of Energy Efficient Homes

Project Scope and Participant Criteria/Responsibilities

In order to assess what effects, if any, energy efficiency measures have on moisture performance in homes, particularly in the wall systems, NAHB has engaged the NAHB Research Center to conduct monitoring across the country on homes constructed to higher energy efficiency targets. The results will provide NAHB and the research participants with valuable real-world performance data.

The Research Center is seeking 20 or more new energy-efficient homes, representing the various U.S. climate zones, to participate in this field monitoring study of wall moisture performance. Qualifying homes should be occupied in order to capture the effects of occupants’ day-to-day habits. Builder names will not be disclosed in the reporting – all sites will be reported only by general geographical location. Builders who qualify for this research program can provide multiple homes for participation in the study.

To conduct the monitoring, sensors will be installed in the selected energy-efficient homes to measure relative humidity, temperature, and moisture content of wood frame materials. The monitoring program will continue for a minimum of 15 months following installation of the monitoring equipment.

Builder Participation

If you are a builder interested in submitting your home(s) for this study, please read the minimum qualifications and requirements for participation below. If you meet the qualifications and agree to the requirements, please contact us to initiate the application process.

Minimum Builder Qualifications

  • Must have built at least three new homes in 2010 and at least 30 new homes since 2000
  • Must have built energy-efficient homes in the past as demonstrated by one or more of the following: HERs rating, EnergyStar certificate, a third-party green program certification, or other similar
  • Must have built air-tight homes with ACH50 of 4 or less as demonstrated by blower door testing

Builder Requirements for Participation in the Project

  • Provide at least one home for participation in the study
  • Sign an MOU with the NAHB Research Center outlining roles and responsibilities
  • Provide building plans to the NAHB Research Center prior to construction
  • Document design and construction practices using a standard form provided by the NAHB Research Center
  • Hire a certified professional to conduct a blower door test and fan air flow rate testing 
  • Install sensors per instructions provided by the NAHB Research Center
  • Install data acquisition module per instructions provided by the NAHB Research Center
  • Activate the internet connection (if requested, internet connection can be provided by the NAHB Research Center)
  • Communicate with the homeowner(s) as needed

NOTE: all installation costs, blower door test costs, and fan flow rate testing costs are the responsibility of the builder

Minimum Wall Construction Details by Climate Zone

Walls Construction
(generic)		 Climate Zones
2-Moist 3-Moist 4-Moist 5-Moist 6 7 4-Marine
2x4/R-13 cavity X            
2x4/R-13 cavity + 1" Foam/R-5   X (X) X     X
2x6/R-20 cavity     X X     X
2x6/R-20 cavity + 1" Foam/R-5         X X  
2x4/R-13 cavity + 2" Foam/R-10         (X) (X)  
Other Per specific research objectives

(X) = secondary priority combination

NAHB Research Center Responsibilities

  • Provide all sensors and hardware necessary for acquiring data
  • Provide installation and location instructions for sensors and hardware
  • Provide technical support via phone to assist with installation as well as other questions
  • If requested by builder, provide internet access for the data acquisition system
  • Acquire the data remotely
  • Analyze the acquired data and report results
  • Maintain confidentiality regarding builder name and exact location of home site, unless requested otherwise by the builder

Manufacturer Participation

Manufacturers of energy-efficient products and systems are also invited to participate in this study by sponsoring test sites with homes built using their technologies. Sponsors can choose whether or not they want to make their participation public information. If you are a manufacturer interested in sponsoring one or more test sites, please contact us.