December 1999, 26 pages
Concrete Forms: Comparative Thermal Performance contains results on energy and thermal comfort performance, as well as computer modeling of energy use. Three homes were built and monitored. One home has an ICF plank system, one has an ICF block system, and one is of conventional 2X4 lumber construction. The homes have identical floor plans. They are located side-by-side on the same street in Chestertown, Maryland.
All three homes, which were unoccupied, were set up for long-term energy monitoring. Two of the homes were also monitored for thermal comfort analysis per ASHRAE Standard 55-1992. Weather data from the site were used in the energy use computer modeling program, Building Loads Analysis and System Thermodynamics (BLAST), to compare predicted energy performance of the homes to actual energy use.
Key findings include the following:
- There was not significant difference in air leakage test results among the three homes. This lack of difference may reflect the dimensions, volume, and relatively limited wall area of these simple, affordable homes.
- The two ICF homes were approximately 20%more energy efficient than the wood-frame house. This difference is largely due to the higher effective R-value of the ICF walls and continuous insulation at the slab.
- BLAST modeling of energy use produced results very similar to actual energy use. The results suggest that the contribution of thermal mass and ground-coupling effects to the overall energy efficiency of the ICF homes was not significant.
While no dramatic thermal comfort differences were apparent between the ICF and the wood-frame homes, several thermal comfort measures showed slight but significant better performance for the ICF homes.
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