Presenting…The Phius 2021 Certification Guidebook

July 28th, 2021

Dear Readers,

The Passive House Institute of the United States (Phius) has officially released the most recent certification guidebook. Yay!! 

You can check out the guidebook here. It is 190 pages…and yes, I “read”1 through the whole thing. Did I understand all of it? Especially the bit about inputting information into the WUFI software? Nope. But was it a great way to get more of a holistic view of what William and I are getting ourselves into? Yup. 

For those who are interested, here’s 190 pages of passive building guidance condensed into 11 bullet points/squiggly lines.2 Again, these are a result of my version of “reading” in this specific scenario. 

“Phius 2021 Passive Building Standard Certification Guidebook, Version 3.02.” PHIUS. July 2021. Chicago, Illinois. Phius Certification Guidebook v3.02.pdf

~ Building to passive standards really is a necessary stepping stone to achieve the Living Building Challenge (LBC). The Energy Petal of the LBC requires a home or building to produce 105% of its energy needs through on-site renewables. Passive building not only makes this possible by reducing operational carbon in the first place, but it also paves the way to make embodied carbon the next beast of a challenge to tackle. Phius Certification Guidebook v3.02. Page 5

~ We NEED to find a Phius Certified Rater (the person who periodically comes out to inspect our home through the build process) that is as close to the Land of the Laurels as possible. Not only would it decrease the burden for them as far as drive time~ especially with our back roads…~ but it would also be nice for us with the whole ‘building on a budget thing’… Sooo….Perry County friends….if any of you are interested in becoming a Phius Certified Rater…that would be cool! 😉 Phius Certification Guidebook v3.02. Page 16

~ William and I will most certainly be pursuing a Phius Performance based certification (William is so crazy excited to play around with the WUFI Passive modeling software….When this portion of the building design begins, I don’t expect to see him for a few weeks). Phius Certification Guidebook v3.02. Page 17

~ Listen…they have an Indoor Pool Calculator to help determine the home’s “energy use due to evaporation and dehumidification for indoor swimming pools.”3 If people are trying to build Passive Houses with indoor swimming pools…then I don’t see a reason we can’t build our home with a green wall or an indoor greenhouse. And a greenhouse means a hobbit door…So I’m obviously going to hard-core push for this to happen now. William is just ecstatic. Phius Certification Guidebook v3.02. Page 22

~ And the question you have all been wondering….how much does Phius certification cost??? Our Phius Performance Path Certification fee for our 1,456 square foot home will be $1,500. This cost does NOT include the cost for additional consulting OR the Phius Certified Rater…which we will most definitely need. Phius Certification Guidebook v3.02. Pages 52 – 53 and 160 -161

~ The WUFI software is free, however. And! There are free tutorials on how to use it. So, that’s nice… Phius Certification Guidebook v3.02. Page 55

~ WUFI, by the way, even requires the input of the energy usage of all office equipment in a home…really, of every device that uses electricity. That is how legit it is. See why none of us will be seeing William for a while? Oh, trust me…he is looking forward to geeking out on this whole energy consumption thing… Phius Certification Guidebook v3.02. Page 77

~ Ah!! And a total “YAY!” moment!! Ya’ know that wall section William is so gosh darn proud of? And models the “perfect wall” design professed by Joe Lstiburek? Well, that wall design is, according to Phius, “…the simplest and most robust wall to design with respect to vapor control.” This is due to the fact that all of our insulation value (our wood fiber insulation) is located on the outboard of our structure (our CLT). We may just have a chance, guys…  Phius Certification Guidebook v3.02. Page 113

~ Annnddd…a part we are currently failing at are Phius’ tips for ‘designing a low-cost passive building’…which is kinda awful. This is due to our large usage of windows (Phius recommends that windows only occupy 10-15% of wall area for single-family houses)…our now more ‘complex shape’ with the possible addition of the mudroom/greenhouse area (Phius says compact shapes are best)…and our loft area (Phius discourages large ‘open to below’ areas in the floor). So, yes. Many “YAY!” moments are short-lived in our endeavor. Phius Certification Guidebook v3.02. Page 158

~ But, hey….the next couple paragraphs down, on that very same page, mentions ‘the perfect wall’ again. There’s that. Phius Certification Guidebook v3.02. Page 158

~ While the Net Zero source energy prerogative is a great goal, and William and I need to even surpass that goal for the LBC, it is also admittedly unrealistic and unproductive in certain scenarios. William and I need to critically look at not only our own home’s energy demands and our own on-site energy harvesting potential, but we also need to keep the realistic and productive restraints of on-site energy generation in mind for our future prefab endeavor. Phius Certification Guidebook v3.02. Page 160


Bam. Done. One hundred ninety pages squished into two pages when you look at it on google docs! If you are in fact really into Passive House standards, I strongly encourage you to “read” the document on your own, in whatever way you like to “read” extensive compilations of great information. 

Thanks for “reading”!

Shelby Aldrich

1. When I say “read” in this sense, I mean the college version of reading. When you are handed a behemoth of a text, and only give yourself a designated amount of time to go through it…you read smarter, not harder. I read the parts that were the most relevant to the home we are building and our overarching goals, and I entirely skimmed over the parts that went over my head and had no application to The Seed. So please don’t quiz me on the guidebook. 

However! I don’t always “read” like that…I do actually thoroughly and holistically read things. Sometimes.

2. All of this information was obtained from: “Phius 2021 Passive Building Standard Certification Guidebook, Version 3.02.” PHIUS. July 2021. Chicago, Illinois. Phius Certification Guidebook v3.02.pdf

3. “Calculators and Protocols.” PHIUS. 2021. Calculators & Protocols: Passive House Institute U.S. ( Accessed on 28 July 2021. 



  1. The PHius CORE prescriptive checklist looks like a good tool for identifying the different elements of the project.
    I would think managing condensation will be the biggest challenge with a greenhouse. The air supply would have to be directed at the windows.
    My professor at GA Tech was an advocate of windowless buildings for energy savings but he seemed to overlook the benefits of natural light.

    • Hey Frank! The prescriptive checklist is definitely an excellent tool to help figure out initial design moves that will help to meet PHIUS standards, we were considering it, since our house is simple in shape and could have used it – up until this greenhouse idea at least! And yes, we will definitely bear condensation in mind while we work with the ventilation supplier. And our triple-glazed PH certified windows should help too, especially when it comes to letting natural light in with minimal impacts to our energy usage – as much as we want to save energy, we surely don’t want to live in a windowless box!


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