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Prefab Green Home: 1st Energy Audit Of The SIPs House Kit!

This is the FIRST of two energy audits.

Energy Audit #1, today's energy audit of the prefab modern house, is as we're at the "This is the modern house kit + cladding + the homeowner sealing around the windows stage", the second will be once we're "done, finished, kaput, as in done, done, done, done, don't ever want to think about anything construction related for at least another week DONE."

Our mission is to create tight, energy efficient, gorgeous passive solar house kits.  I admire rated, certified, even more stringent approaches, like Passive House standards, maybe we'll do this in the future, but we achieve what we want in an energy efficient home while incorporating great modern design on an average, reasonable budget.

Some highly energy efficient homes incorporate two door chambers to prevent temperature loss.
I picture the way I live, and it is just too chaotic and messy to make such an entrance successful.  Can you imagine a couple struggling with the stroller, dogs still on the leash, juggling a bag of groceries and a baby on one hip, getting the key in the door lock then screaming to the spouse...
"Quick honey, seal the chamber, we're losing LEED points!"
Obviously if you live in a severe climate, it makes sense. But we're in Normal Rest-o'-Tha-World here.

We're a muddy, raggedy bunch here... why do ya think we're bandits?
You can increase the thickness of the house kit panels, choose even more efficient doors and windows (our casa ti prefab green home is spec'd for Jeld-Wen and our, SIPs house kit with two stories, The R1 Residential, is spec'd for Marvin Integrity), seal it up even tighter... but my focus is on affordable energy efficiency in our prefab green homes, so we chose great solutions that fit within a moderate budget.

The average quote for the casa ti windows is currently about $9,000-$10,500. If you would like to spend more on windows to make 'em nano-crazy-efficient, go for it, we can adjust the shop drawings. But expect the added cost.

We hired energy rater Guy DuBois, of No Energy Loss, to come out and inspect the modern prefab house kit
These are the notes I jotted down during his cell phone call to me en route from the land. Mr. DuBois will guest blog later this week with more real data, but here are his initial verbal impressions of the still-under-construction, still-not-completely-sealed house kit:
"Well, we certainly smoked up your house quite a bit, there was nowhere for it to go!"
(Copeland's note: Ummmm, I assume he means it was some kind of smoke air test thingy? I hope he didn't mean he smoked in mah house?!?)

Ok, on to Mr. DuBois:
"Those windows - they are worth the money, they were very well sealed."
Copeland's note: Handsome Husband also sealed around the frames... OK FINE I will just stop commenting and just TYPE what he said!
"Your husband did a good job of sealing around the windows... there are two areas he also could look at if he wanted to seal further- along the south eave and that back door threshold.

It is surprisingly tight. I don't know why I say surprising, but I guess I didn't expect it to be so tight, even though I should have."

[Copeland's note: Um, yeah, thanks Mr. DuBois... ; ) OK, OK I'll stop commenting!]
"I'll go back at completion and run more tests.  This was a good time to go out there because if there were problems you could address them before everything was closed up.

As you know, it's so tight you really must have mechanical ventilation, which you will be installing (HRV), which is critical in these energy efficient homes. Most homes, most traditionally-built homes, leak willy-nilly so you don't ever have to worry about air quality, but in energy efficient homes like these they're so air-tight that air-exchange is imperative.

I saw very little air leakage... there is some thermal bridging you can address if you want but you certainly won't have a problem heating and maintaining good energy efficiency, that's for sure. How does it compare to a "normal" house? Superior!"
To continue to seal even further, concentrate on the areas where there is lumber vs. SIP (structural insulated panels)- the doorway header, add insulation around wooden framing, and if you're in really severe climates, you could add an exterior seal.

Mr. DuBois makes a good point:
"But you have to consider the climate- maybe if you're in Alaska or really south Florida you would want to consider that, but... we're in Virginia, how much gain will you really get by doing all that?!? You already know that with your off grid systems, comfort will never be an issue.

I will be punching in everything I did today and coming back with some data next week... you're not trying to get this house certified, so this is just more FYI info, but it will be cool to compare today with when you're done at the end of the project."
He also said that the amount of leakage currently (we're still not done sealing) in the prefab SIPs passive solar home is equivalent to about 6 x 6 inches, smaller than a basketball. Handsome Husband is chasing that number, with sealant in hand.

Later, Handsome Husband arrived home, and I had all these pictures and video to look at... and share with you now.

Mr. DuBois sets up...

SIPs House Kit Energy Audit #1 of 2

They start do to the smoke test and pressurize the modern house kit. SUDDENLY, a clerestory window pops wide open!  It had looked closed, but hadn't been closed totally, which certainly that had also contributed to our loss of temperature this winter at night!  It is securely locked now... : )

Smoke And Open Windows In The Affordable Prefab SIPs House

So, they pressurize again...

Energy-Audit-#1 of 2 In The Affordable Prefab Green Home

And then....they freakin' fill mah house up with SMOKE!
Note the comment about the south edge- later they discovered that when the door was installed they didn't put any sealant under that south door.  You as a home owner can seal that more if you live in a severe climate area. I knew the windows worked really well for our budget, but am pleased with how impressed he is! : )

Energy Audit 1 of 2: Smoke And Windows

Here Handsome Husband decides he's going to track down that durned elusive number.

Energy Audit 1 of 2: Husband Wants Passive Perfect

Then they go tramp around outside looking for leaks.
If there were gaps, you'd see the smoke drifting out.

Energy Audit #1 of 2 of the Prefab Net Zero Energy Green House

Check out what it looks like when they crack the door (and how hard it was to open because of the pressurization - because the house kit was so tight!).


...And then they start calculating...
Which Mr. DuBois will go into more in his guest post soon.

Energy-Audit-01-16-2010-36 from Copeland Casati on Vimeo.

And thaz it, the latest from our passive solar green home!

Here is Handsome Husband's summary:

"This wraps up the initial test of the house kit. We now know what simple steps we have left to optimize the envelope of the SIPs house, and we look forward to the final testing after construction is (finally) completed. The general goal and idea of the casa ti has passed Mr. DuBois's testing with flying colors, as we already suspected in the prefab house kit's performance over the last few weekends where the design and structure were able to give us relative comfort in a hostile climate.

The great thing about the delays in this project is that we're able to thoroughly test the house kit without further improvements, this allows us to confirm the performance a passive solar house kit built with SIPs."

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At 1/17/10, 12:46 PM , Blogger George said...

Very, very, impressive!

At 1/17/10, 4:54 PM , Blogger Lizzykewl said...

How exciting!

At 1/17/10, 5:49 PM , Blogger Passive Solar Prefab Homes said...

Realizing that (currently- we're still not done sealing) the amount of leakage is less than the size of a basketball helps me visualize determination to conquer it.

"Really? You want to play ball? Fine, leakage, GAME ON!"

We already know we'll reduce a lot of that when we finish adding foam to *around* the still-exposed foundation, but it will be fun to see where else we can better insulate, and what the final numbers will be. : )

At 1/18/10, 10:13 AM , Anonymous Gina said...

I know what it's like to deal with leakage, but oh, the satisfaction, once it's been fixed! Carry one!

At 1/18/10, 9:16 PM , Blogger Passive Solar Prefab Homes said...

Loved following your link to your own project and learning about your permaculture- as you know, it's not just about "the house" - once we're done with that project we have a lifetime of preserving the land we bought while promoting sustainable living.

At 2/19/10, 3:46 AM , Anonymous Anonymous said...

nice post. thanks.


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