CET Conducts Home Energy Rating of Straw Bale Home
By EcoFellow Sonja Favaloro
Every contractor that CET’s New Construction Department works with focuses on minimizing energy usage and environmental impact, which often means utilizing cutting edge technologies. However, there are many alternative methods to achieving the same goals. Recently, CET staff had the opportunity to tour a house with straw bale insulation and locally milled lumber that is under construction in Buckland, MA. It is projected to be highly energy efficient, though it looks very different from most other efficient buildings we have consulted on.
CET’s New Construction Department has been hired by Yeoman Design Build to complete a Home Energy Rating of this project for compliance with the MA Stretch Energy Code. The projected HERS index for this home is 49, meaning it will likely be just over 50% more efficient than a home built to minimum code standards. It is the first house of this type that CET has worked with!
This house is an example of combining natural and high-tech green building techniques to create a sustainable and energy efficient structure. Natural building methods used for this house include straw bale insulation in the walls, clay plaster for the interior wall surface, and lumber mostly harvested and milled on site. The building also incorporates modern green building elements such as double pane windows and an electric heat pump system.
This Buckland house is a prototype project to help Yeoman Design Build develop a system that is competitive in terms of both cost and time. For example, one aspect of the project that helps with shortening construction time is using a stick frame, as opposed to a timber frame. Timber framing is a more time-intensive technique commonly used with straw bale wall systems. Yeoman Design Build’s owner, Mike DeSorgher, explained that he hopes this project will help him learn best practices for building sustainable, natural houses so that he can continue to do projects like this in the future. He also mentioned that the Massachusetts building code will soon include straw bale as a category for residential structures, which is an important step towards making natural building more widespread and accessible.
Here are a few of the house’s special features:
Most of the lumber and wood were harvested at the building site and milled a few feet from the house. This is one of the most environmentally beneficial choices the contractor made, because if he had paid another company mill the lumber, it would likely have been sent overseas to be processed. This would have greatly increased the carbon footprint of the project.
The straw bale walls are coated with natural plaster.
For more information, visit their website or call Mike at 413-834-1499.
If you are a builder interested CET’s New Construction services, including HERS ratings, LEED Certification and ENERGY STAR® Certification, visit our website or call us at 413-586-7350.