The Impact of Concrete Balconies on Thermal and Whole Building Energy Performance.
The research report completed by Morrison Hershfield analyzes the impact of structural thermal breaks to reduce the overall consumption of heating energy and increase interior surface temperatures. Read the Executive Summary of the Research which shows structural thermal breaks can reduce overall heating energy consumption from 7 to 14%, and raise interior surface temperatures by roughly 13ºF, versus conventional concrete slabs.
The Morrison Hershfield (MH) report, Thermal and Whole Building Energy Performance of Thermal Break Technology for Concrete Balconies in High-Rise Multi-unit Residential Buildings analyzed the impact of thermal bridging (energy loss, condensation risk and thermal comfort) regularly caused by penetrating a building envelope with a balcony slab, for three concrete balcony types:
• Conventional solution--Cantilevered concrete balcony with continuous concrete slab penetrating through the building envelope,
• Site solution--Cantilevered concrete balcony slab with intermittent insulation placed between continuous concrete beam connections
• Schöck solution--Cantilevered concrete balcony with an Isokorb® CM20 thermal break
Energy Plus for Whole Building Energy Model
The Morrison Hershfield research team used a whole building energy modeling software, Energy Plus, to analyze a common multi-unit residential high-rise building – a 32-floor, 422-unit structure, with 356,608 sq.ft. of floor area, 163,321 sq.ft. of wall area with roughly 40% "vision glass" (windows, glass doors), and 3.5% of exposed cantilevered concrete slab area (balconies).
Schöck Isokorb® Reduces Heat Flow by 75%
The study found that Schöck Isokorb® delivers an effective thermally separated slab, with a reduced U-value. Schöck's solution cuts heat flow through or around the slab by 75% compared to a conventional continuous balcony. In contrast, the slab with intermittent concrete connections provides only a 21% improvement over the conventional balcony slab.
Warmers Floors with Schöck Isokorb®
A principal benefit of the Schöck solution is that the floor is much warmer in the winter than with the other construction methods. The Morrison Hershfield study clearly shows the floor slab at the perimeter is warmer, thus providing benefits for condensation resistance and thermal comfort.
Reduced Cost to Meet Building Codes
The study notes that Schöck Isokorb® can help meet Building Code requirements without requiring investment in other costly improvements related to the building envelope.
Tenants and owners of new developments expect high standards, thermal comfort and energy efficient buildings. This research by Morrison Hershfield reflects that Schöck Isokorb® not only helps to fulfill these immediate expectations, but is also an investment in performance and quality building.
The Appendix to the full report also provides further information on the calculations and scenarios.