Ben,
 
I'm going to put this back on the listserve, as I think it's too important to keep to ourselves.
 
You seem to think it's near impossible to build a freeze-proof house.
 
The very first Larsen Truss house I built in Western MA (7000 HDD) was designed to be freeze-proof and it was. It was built for a couple of potters who had to go to a Florida craft show every February for three weeks, and the house had only a small Yotul woodstove in addition to the passive solar - no backup.
 
The first winter they left it empty there was no sunshine for the entire three weeks and the indoor termperature never dropped below 45. This is accomplished by NOT isolating the conditioned space too much from the earth underneath. That house had a 4' deep rubble trench foundation with vertical R-10 XPS on the outside and up the shallow concrete grade beam. The flagstone floor was placed over VB, 2" XPS and many tons of gravel fill.
 
This is also a significant advantage of the shallow, frost-protected foudation - as it remains moderately ground-coupled to earth that warms up during the heating season (likely 50-55 in VT) so that the delta-T is much less than to the outdoor environment and the house cannot freeze except in the most extreme conditions.
 
- Robert

--- On Mon, 12/29/08, Ben Graham <[log in to unmask]> wrote:
Robert,
I have been in the same boat.  But my perspective has changed.  I have always thought that if you could build a house that wouldnt freeze in the winter, you have done something amazing.  I dont know of one house in Vermont that accomplishes this.  Once you have accomplished this you can modify the temperature as you like, open windows, go outside, whatever, but you have the baseline efficiency to work with.  Its really about the energy use not uniform climate.  So what we are talking about is better thermal breaking, more insulation, better windows and doors, and simpler, non-combustion forms of heating. When you look at the efficiency of these houses they go beyond net zero.
    You seem to think this is an easy task.  I have studied many case studies including a project with Amory Lovins, all of which need heat to keep from freezing and considerable amounts of heat to keep inhabitants comfortable.  I would be way into seeing this accomplish and would want to support with documentation.
    There are many people who would benefit from this type of house, which is different than net zero.  I believe investing in insulation is more sustainable than investing in fuel to make up the difference.
    Either way, one of these houses should be built to see how it performs.  And we should try it with natural materials.

Cheers,
Ben

PS,
I just heard NH wants to start charging people for emergency remote rescues.
   


On 12/29/08 2:13 AM, "Robert Riversong" <[log in to unmask]> wrote:

Ben, et al:
 
I've been aware for some time of the PassivHaus movement, but it hasn't drawn me any more than the Net-Zero movement has. It all seems so very extreme and unnecessary.
 
For one thing, we don't need to live in a perfectly uniform indoor climate. I think it leaves us less healthy and less adaptable as creatures.
 
Secondly, I believe that with some modest additional cost, I could turn one of my modified Larsen Truss homes into a Net-Zero Heat home. Those modifications I described should allow that house to reap all if its heating needs from the sun and internal gains.
 
And, if a home-owner wanted to add PV or wind generation (at considerably more expense), it could be Net-Zero for all it's energy needs.
 
I don't think it has to be as difficult or high-tech as PassivHaus suggests.

--- On Mon, 12/29/08, Ben Graham <[log in to unmask]> wrote:
From: Ben Graham <[log in to unmask]>
Subject: Re: Passive Houses
To: [log in to unmask], [log in to unmask]
Date: Monday, December 29, 2008, 12:30 AM

These are standards for Central Europe and would be different for colder climates.  We need to start verifying energy use in our projects because analysts are finding the actual use in most LEED projects are very different than designed.  In fact passive house certification is based on certified reports of built structures.
    If you think you are able to meet these standards we should get one of your buildings certified because there are not many out there.  
    I attached a study of existing project in Germany with detailed drawings.  Notice threshold and window details, the likes of which are not available in the states and only comparable with Thermaproof windows.  Also notice the 12 of insulation under the slab and remember that in our climate it would need to be more, to the point where shallow frost protected foundations wont even work anymore!  This is beyond superinsulation, were talking better than R-60 walls. Houses in this climate would probably require external insulating covers at night.

Enjoy the reading! And converting.
Ben

On 12/28/08 11:55 PM, "Robert Riversong" <[log in to unmask]> wrote:

Ben,
 
I was using the standards from the website you linked to.
 
Performance Characteristics

  • Airtight building shell 0.6 ACH @ 50 pascal pressure, measured by blower-door test.
  • Annual heat requirement 15 kWh/m/year (0.048 therms/sf)
  • Primary Energy 120 kWh/m/year (0.38 therms/sf)

In addition, the following are recommendations, varying with climate:
  • Window u-value 0.8 Watt/m/K  (U-0.14)
  • Ventilation system with heat recovery with 75% efficiency with low electric consumption @  0.45 Wh/m3
  • Thermal Bridge Free Construction 0.01 W/mK ( 0.006 BTU-ft/hr-sf-F)

And I was comparing them with both the Energy Star projected energy use numbers and my own spreadsheet, which has always closely matched actual consumption.
 
- Robert

--- On Sun, 12/28/08, Ben Graham <[log in to unmask]> wrote:
From: Ben Graham <[log in to unmask]>
Subject: Re: Passive Houses
To: [log in to unmask]
Date: Sunday, December 28, 2008, 11:25 PM

Thats good to know Robert.

Theres another rub that makes the Passive House concept different than LEED and much better for it.  It uses actual energy usage and blower door results.  Not just designs.
Which energy use standards were you using?  They havent published standards for our climate yet.  Probably the closest ones are the ones being developed for lapland and sweden.

Ben


On 12/28/08 10:17 PM, "Robert Riversong" <[log in to unmask]> wrote:

Ben, et al:
 
I just crunched some numbers and discovered that if I modified the superinsulated house I built last year by increasing the south glazing by 60sf (from 138sf to 198sf), using moderate solar heat gain triple glazed instead of double lowE, and replaced the exhaust only, passive inlet ventilation system with a 75% efficient HRV, then it would have met all the PassivHaus standards.
 
Maybe next time.
 
- Robert
 


--- On Sun, 12/28/08, Ben Graham <[log in to unmask]> wrote:
From: Ben Graham <[log in to unmask]>
Subject: Passive Houses
To: [log in to unmask]
Date: Sunday, December 28, 2008, 4:39 PM

  I wanted to let people know about one of the most far reaching and
innovative energy efficiency movements in construction called the Passive
House Movement.  It started in Germany perhaps 12-15 years ago spurred on by
the Kyoto Protocol and the German Government.  Over 15,000 of these houses
have been built in Central Europe and the concept is spreading fast.  There
have been few cold climate models but there are many experiments underway.
The idea is similar to net zero but more innovative. You can find out more
details in the links below.

    You can read a report of the 3rd annual Passive House Conference in the
US just held in Duluth, MN here:
http://www.energybulletin.net/node/47457

    And you can visit the US passive house center here:
http://www.passivehouse.us/passiveHouse/PHIUSHome.html

There is even a smaller movement of building designers working on combining
the Passive House concept with Natural Building.

    The passive house model is based on real use rather than designs and is
backed up with fuel use receipts.
    If anyone knows of anyone trying a Passive House in VT, please let me
know.

Cheers,
Ben

Those who give up freedom for safety, deserve neither.
Benjamin Franklin
__________________________________________________________

Ben Graham
www.naturaldesignbuild.us
Natural building/design services/workshops/consulting

Integrating Culture and Nature
802.454.1167



Those who give up freedom for safety, deserve neither.
Benjamin Franklin
__________________________________________________________

Ben Graham
www.naturaldesignbuild.us
Natural building/design services/workshops/consulting

Integrating Culture and Nature
802.454.1167





Those who give up freedom for safety, deserve neither.
Benjamin Franklin
__________________________________________________________

Ben Graham
www.naturaldesignbuild.us
Natural building/design services/workshops/consulting

Integrating Culture and Nature
802.454.1167





Those who give up freedom for safety, deserve neither.
Benjamin Franklin
__________________________________________________________

Ben Graham
www.naturaldesignbuild.us
Natural building/design services/workshops/consulting

Integrating Culture and Nature
802.454.1167