Dr Allison Bailes III uses his PhD in physics and his background in teaching, to educate the world about better buildings. Through his company Energy Vanguard, Dr Bailes has been recognised as a great communicator, turning complex ideas like relative humidity and psychrometrics, into understandable fundamentals for better home performance.
The Phsyics of Good Buildings
Dr Bailes was a physicist first. He was then inspired by a professor who build an off-grid eco house. So impressed in fact, that Allison tried his hand at building, despite having no real ‘hands-on’ experience. This is where he learned to love the art of building and bringing physics into a very practical application.
Crawl Space Encapsulation
I’m familiar with laying down a ground vapour barrier to reduce the dampness from the ground under a house, rising up into the house. But I’ve always understood that ventilation around the perimeter foundation wall is critically important for helping to keep the subfloor space dry. This is actually written into the standard by which most New Zealand homes are now build (NZS 3604).
In this interview though, Dr Bailes explained to me that air coming into the subfloor will have the same relative humidity as the ambient air. When this cools (as it’s likely to do under a house), the relative humidity will rise and moisture will be drawn into the house. Hence a large part of Allison’s early days in business were spent ‘encapsulating’ crawl spaces – completely sealing them, in order to reduce internal moisture.
Priorities for a Good Home
Exactly how to create a better place to live, depends on your circumstance and your objectives, but Dr Bailes has two key recommendations:
- Make your home airtight. Yes, airtight. This is a good thing.
- Once your house is airtight, get some good mechanical ventilation.
Good Mechanical Ventilation
Pumping air in from your roof cavity is not considered ‘good ventilation’, in fact Allison was confused when I tried to explain what most New Zealanders think of when you say ‘HRV’. For a good rundown of truely effective ventilation, check out my chat with Grant Anderson from Fantech.
You can find Dr Bailes…
- On the Energy Vanguard wesbite
- Subscribe their building science newsletter
- Energy Vanguard on Twitter
- Dr Allison Bailes on Twitter
- Dr Allison Bailes on LinkedIn