Do you want an energy efficient house?

To ensure an energy efficient house you must deal with the following items in the order as listed

1. Water

2. Air

3. Vapour

4. Thermal (star rating)

Hang on! Why is thermal at number 4?

It is at number 4 because it won’t work unless you address 1, 2 & 3. 

1.If water gets into the structure via rain, flood or leaks, air and vapour will also certainly get in. Wet insulation doesn’t work. A wet structure causes health issues and structural damage. (Thermal doesn’t work).

2. If Air gets into the structure it carries dust, toxins, pollen, and MOISTURE which in turn causes health issues and structural damage. Air moving through insulation also dramatically decreases the performance of the insulation. Air leakage from the building can also equate to up to 60% of your heating/cooling bill. (Thermal doesn’t work).

3. If Vapour gets trapped in a structural assembly it can condense on an internal surface. Again, this MOISTURE causes health issues and structural damage. (Thermal doesn’t work).

So, when we talk about increasing the thermal performance of a building it is important to get our priorities right. Increasing from 6 stars to 7 or 8 stars won’t work unless we address items 1-3.

Increasing insulation values can actually make our moisture problems worse if we treat ‘Thermal’ in isolation and don’t address moisture & air management. At the international Builders’ Show I had a discussion with building scientist, Mark LaLiberte, from Construction Instruction . He said, “Treating Thermal in isolation is insane. You need to address Water, Air and Vapour first then thermal will follow nicely. If you focus on thermal without a good moisture and air managment strategy you’re asking for trouble.”