A conditioned crawlspace is a crawlspace constructed and insulated so that it is part of the conditioned space of the house. Conditioned crawlspaces remain less common than vented crawlspaces despite performing better in terms of safety, health, comfort, durability and energy consumption.
The following documents examine the benefits of conditioned crawlspaces, how and why they work, and how to understand and interpret relevant sections of the building code. Related documents, such as those discussing basement insulation more generally, are also included in this section.
This paper discusses the differences between vented, unvented and conditioned crawlspaces. Best practice construction techniques and assemblies for conditioned crawlspaces are discussed, the results of a field monitoring program are presented, and the code language addressing crawlspaces is explained.
The following report is an excerpt from the 2010 Building Science Corporation Industry Team Building America Annual Report. Many concerns, including the rising cost of energy, climate change concerns, and demands for increased comfort, have lead to the desire for increased insulation levels in many new and existing buildings. Building codes are improving to require higher levels of thermal control than ever before for new construction. This report considers a number of promising foundation and basement insulation strategies that can meet the requirement for better thermal control in colder climates while enhancing moisture control, health, and comfort.
Successfully executing strategies to control bulk water for foundations is critical for building durability, indoor air quality, and creating acceptable conditions and/or living spaces within the foundation space. Although the energy impacts of properly done bulk water control are small to insignificant, it should be considered a base requirement for any high performance house. In addition, measures such as basement insulation are predicated on properly managed foundation bulk water.
Basements can account for up to one quarter of the typical energy consumption in a house. Therefore, insulating foundations is a critical measure for achieving high performance buildings. This is important in both new construction and retrofits of existing buildings. The fundamental problems and “best practice solutions” for moisture-safe basement insulation have been well established. However, many foundations are damp (either due to bulk water or capillary “wicking” of moisture) or of a type of construction that is not easy or straightforward to insulate (such as rubble foundations). Damp foundation repair methods can be “leveraged” to provide energy efficiency benefits. An example of this “hybrid” approach is spray foam insulation, which can be an effective means of liquid phase water control (leaking basement), vapor phase water control (diffusion and air leakage transported condensation) as well as an effective insulation.
Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation to build new construction net-zero energy houses in Massachusetts under the Building America program. There are three communities that are being constructed through this partnership: Devens Sustainable Housing (“Devens”), The Homes at Easthampton Meadow (“Easthampton”) and Phase II of the Coppersmith Way Development (“Townsend”). This report covers all of the single-family new construction homes that have been completed to date. The houses built in these developments are net zero energy capable homes built in a cold climate. The set of measures offered by the developer exceeds the 30% energy saving goals set by the Building America program for New Homes in the cold climate for 2013. The houses will contribute to developing solutions and addressing gaps in enclosures and space conditioning research.
