Efficient prefab?
 

I mentioned to a coworker that I was thinking about building a small, efficient house, and he brought up the topic of prefabricated houses. Viceroy is a company from Southern Ontario who can build houses here fairly inexpensively and very rapidly. All of Viceroy's houses seem to feature good Ar-insulated windows, 2x6 construction, and generally good attention to insulation and comfort.

Are there any companies out there shipping prefab houses that meet, or come relatively close to meeting, Passivhaus standards?

Viceroy doesn't give out free copies of their catalog, even online, but I did find one of their houses here:

Niagara

http://gastoninc.com/Blue/niag3.jpg

The above house is about the right size for me at the moment, at 624ft² on the outside (575ft² inside the exterior walls). It's not as well insulated as I'd like, but I like the layout. Most of the windows are facing the same direction, which should be south. It's very flexible, with an interior layout available for a one-floor or a two-floor variant. It can be built on a basement, or built above a finished lower floor with two additional bedrooms.

I would like to see it build above a garage. In the event that I should sell the house or have a large family, a detached garage could be built, and the lower floor converted to living space. That would make it a respectable 1248ft². Or maybe I'd just leave room to the side to double the square footage later.

I have a while to think about what kind of house I want to buy or build, but a prefab small house would be very attractive.

Prefab Passive Houses certainly are being made in Europe. They are trucked out to the site and assembled amazingly quickly. And yes, they meet Passive House standards.

If I'm not mistaken, they are out of one of the Scandinavian countries... Norway maybe?

I have seen a couple of documentaries that described the whole process.

This is really the kind of thing that would make a glorious dent in our crazy energy consuming ways.

I think you are on the right track, such a business may already exist. You might try sending some emails to some of the Passive House organizations (Passive House US & Passive House Canada), there's an excellent chance that they would know of the existance of such a biz.

Also, I think there may be some leads here.

Good luck, you're definitely moving in the right direction.

-AC_Hacker

They do make some green prefabs.. Found a story in the NYT..
Posting - Designed, Delivered and Sealed - NYTimes.com

Here's the builder site:
New World Home

Xringer, those are modular homes, which I hadn't even thought about. Modular homes are built in a factory and trucked to the site, while prefab homes just have the framing and some subassemblies done in a factory and are assembled on site.

Due to shipping constraints, the New World homes are 15.75' wide. Hence the olde-fashioned styling, and the large percentage of floorspace spent on hallways. Here's a link to the New World Homes floorplans: http://blog.newworldhome.com/wp-cont...Small_1026.pdf

AC_Hacker, thanks for the link. I'm sure there's lots of good reading out there, but the signal to noise ratio is a bit low.

I doubt that this meets your needs but it is certainly an interesting type of prefab home.

Cabins | Monolithic

I agree, motivation does get overestimated.

-AC_Hacker

Passive House - First Steps...
 

I came across this little ruby while I was wandering about on the web.


Although it's intended audience is European, and the examples are aimed at that audience, there are some great ideas here. It would be very useful if the above chart could be adapted to N. America.

But even so, it is very interesting the difference that an 80% Heat Recovery Ventillator makes in wall thickness vs. a 60% HRV.

-AC_Hacker

In order to get to passivhaus levels you will need 16" - 18" walls (assuming you use cellulose) with no thermal bridging at all. I doubt you will find exactly what you want already set up for you but it wouldn't be too hard to adapt something to meet passive standards.

I did find out that at least there is a firm in Canada that designs Passive Houses, and they have certified builders, also in Canada, with whom they have co-ordinated working relations who are qualified to properly execute the designs. They are also trying to get Passive House qualified builders in the US.

From what I have been able to find out, there are stringent techniques used to achieve an air-tight house that go way beyond what would be considered normal building practices. And then there are the techniques used to get the required insulation levels. So among areas of focus are:

• superinsulation
• airtight construction
• mechanical heat recovering ventilation
• high performance doors and windows
• window placement to minimize heat loss & benefit from solar gain

High performance doors and windows go considerably beyond what is generally available in the US.

I did find that Certified Passive House Consultant Trainings are taking place...

...and that they are screening for serious qualified people for these trainings...

...at first I thought it was a trade association thing, closing ranks, but then I came across this link to passive house related building practices, and I remembered that what is now known as Passive House actually started with the Super Insulation initiative and also combined the Passive Solar ideas, and was then picked up by the Germans who refined the ideas and devised a way to generalize construction for any building site and climate. (by the way, the listed 'best practices' manuals are not all currently available, but if you make use of archive.org, you can still find them.)

So I think that what is going on is that Passive House organizations world wide are making a very steep claim, namely that energy use will be 10% of 'normal, well-insulated homes'... and they want to make sure that homes that carry the Passive House name actually achieve that goal.

From what I have read, trying to retrofit a house to Passive House standards is simply not possible, but it is possible (not easy) to get to 20% energy use of 'normal, well-insulated homes'.

I know that I would be quite pleased to get even close to that.

So, "...wouldn't be hard...", wouldn't be too right. Meeting Passive House standards is a very high bar.

-AC_Hacker

Yeah in order to reach the level of tightness and the lack of thermal bridging found in a passivehaus you really need new construction. To meet the standard you need no more than .6 ACH @ 50, which is pretty hard to do even in new construction much less in a retrofit. Although I think that you could get lower than 20% with a retrofit. I'm buying a house so we'll see, won't we?