New buildings account for a relatively small percentage of the energy used in the building sector. Retrofitting existing housing and commercial/industrial facilities is an important goal in terms of energy savings. It is also a complex endeavor, with many factors to consider, from preserving historic features to controlling costs.
The following articles and reports discuss a wide variety of materials, situations and techniques that may be encountered when undertaking an energy-efficient retrofit. As well, many case studies are provided to illustrate how to do retrofits right.
An edited version of this Insight first appeared in the ASHRAE Journal. You have got to love salesmen. They figure things out way before physicists, usually before engineers and certainly before greenie weenies. They found, what we should all know, that it is much more cost effective to fix the enclosure so that the actual system that you need is small and therefore does not cost much to install and does not cost much to operate. Oh, by the way, this approach also saves energy. Who knew?
This paper is from the proceedings of the Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference, December 5-9, 2010 in Clearwater, Florida. The issues of climate change, energy security, and economics are all strong drivers for improving energy efficiency levels in a variety of sectors. In residential construction, although some inroads have been made in new houses, the stock of existing housing represents a huge opportunity for energy retrofits. The vanguard of these efforts has been pushing toward retrofitting very high insulation levels (i.e., “superinsulation,” or “deep energy retrofits”). Several cold-climate residential retrofit projects have been completed using an exterior insulation approach on light-frame above-grade walls. This type of retrofit is a reasonable step if a recladding of the building is already being done for aesthetic or ongoing maintenance reasons. The methods demonstrated here result in walls with insulation levels in the R-35 to R-40 range. This paper presents many of the lessons learned from these experiences, including overall enclosure strategies, such as air barriers, drainage planes, and moisture control. Several case-specific solutions to particular problems are described, including exterior air barrier approaches, wall sill replacement, and several approaches dealing with window penetrations. In addition, detailing recommendations and economic analysis of these measures are presented. Hygrothermal simulations were run to evaluate the changes in sensitivity to moisture intrusion due to these retrofit measures.
