Practising building science, also known as a “systems approach,” means accounting for the ways all building components interact, including the foundation, walls, lofts, roofs, doors, windows, insulation and mechanical systems.
Doing so is critical to optimise building performance and prevent building failures.
The building occupants must also be educated on how to behave properly to limit energy losses; the most optimised building with the best insulation will be useless if the occupants do not respect the environment.
The Principles of Building Science
- Creating a continuous air barrier combined with proper mechanical ventilation
- Providing thermal resistance and limiting heat bridges
- Managing moisture
- Improving indoor air quality
- Using appropriate heating system
How Spray Foam Plays a Vital Role
Building scientists are now stressing the importance of air barriers like spray foam insulation in building design and construction. This is partly because many buildings constructed in the past had no air barriers and experienced major failures in terms of moisture damage and mould caused by condensation, which stemmed from air leakage.
In addition, research shows that without an air barrier, insulation cannot deliver optimal energy efficiency or comfort. This is why blower door tests are commonly required to measure airtightness in new or renovated buildings.
Limits of U-Value
U-value measures insulation’s ability to limit conductive heat flow (heat that is transferred through it). But the primary method of heat transfer is not conductive heat flow — it is air leakage, which can account for up to 40% of a property’s energy loss.
In addition, U-value only does so much to prevent even conductive heat flow. Beyond a certain point, improving insulation U-value makes very little difference, if any. Above a certain thickness of insulation material the heat flow reduction due to conduction reaches a plateau. In fact, the cost of improving U-value alone can actually far outweigh the energy savings that result, meaning it will take much longer to break even.
Therefore, the best way to increase efficiency is not merely to improve U-value, but rather to combine U-value with an air barrier. Synthesia spray foam insulation provides both in a single step.