138 Dr. Allison Bailes Energy Vanguard

Dr Allison Bailes
Dr Allison Bailes III, Physicist, educator and co-founder of Energy Vanguard – the source for training and consulting for good performing homes.

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.

Training with Energy Vanguard looks kind of fun. This is the most interactive psychrometric chart I've seen.
Training with Energy Vanguard looks kind of fun. This is the most interactive psychrometric chart I’ve seen.

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).

Dr Allison Bailes challenged my understanding that foundation vents are a good thing.
Dr Allison Bailes challenged my understanding that foundation vents are a good thing.

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:

  1. Make your home airtight. Yes, airtight. This is a good thing.
  2. Once your house is airtight, get some good mechanical ventilation.


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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.


Follow Allison

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  • Summary: Remember it’s important to know that you don’t know what you should know, you know. This is what we have been reduced to, an entire industry that is confused about what they get paid to do and how to do it with no one complaining about it. Take this advice, take the money and keep your traps shut, because its what everyone else is doing. Enough said on this topic about experts and what they don’t know. P$ no charge.

    • mcutlerwelsh

      I hope that I’m contributing to removing some of that confusion.

  • What seems to be consistent for sure is that Experts are as confused as much as everyone else, Don’t believe anything you see or hear, because it will change over time, there is no truth or right answer. On a more positive note there’s one constant and that is BS, you can take that to the bank.

    Look, most of the experts need to have a position or lose credibility as experts which they leverage to get work and pay bills, being correct is not that important. You must admit that advice comes from all directions and seldom match unless you find a flock of :SHEEP. ie. Leed, Passive House etc.

    • mcutlerwelsh

      Thanks for your comments. From what I’ve seen to date, both LEED and Passive House are flocks that I’m happy to follow, or at least help promote the benefits.