[Greenbuilding] PassivHaus and NZE comparison
Gordon Howell -- Howell Mayhew Engineering
ghowell at hme.ca
Wed Jan 26 11:22:49 CST 2011
Hello Ross and John:
May I recommend that comments on solar PV on NZE homes be made in the
company of facts and knowledge.
The first NZE home in Edmonton cost $110k more than standard
construction, see <www.riverdalenetzero.ca>. If we built it as
standard construction, it would have cost $250k for the solar PV
system (in 2008) and have been 205 m2 in area. No-one in their right
mind would do something like this ... instead we added energy
efficiency measures (envelope and appliances) until the incremental
capacity cost ($/kWh/year) of energy efficiency was roughly equal to
the incremental capacity cost of PV at the time. Then because energy
efficiency is so vastly cheaper than PV (even now) then the
incremental cost of the house was reduced to about $25k for energy
efficiency and $35k for solar thermal, and $50k for solar PV.
The next two NZE homes, Mill Creek <www.greenedmonton.ca> and
Belgravia, are in around the $70k incremental cost... why? Same
energy efficiency measures, more passive solar (south windows), very
simple solar thermal (on Mill Creek) and zero solar thermal (on
Belgravia) and price of PV continues to plummet. Add to this that
the Alberta government provides a $10k incentive for EGH 86 houses
and the incremental cost to the homeowner is around $60k.
So I wish PH people would get off the pot on their comments about
"The Net Zero homes use exorbitantly expensive renewable energy
systems to push them to zero"... we only put on solar PV when the
ultra energy efficiency measures are in place... and these measures
roughly equal the PH standard.
NZE homes aren't political statements or science experiments... they
are homes that people are desiring to purchase... you wouldn't go
around and say that granite counter tops or BMWs are political
statements and yet PV has superior economics than these
products... dismissively referencing these houses as "science
experiments" is not appropriate.
Solar PV modules (which are not called "panels") have warranties of
25 to 30 years (and they are working on 40-year warranties) and
degradation rates of about 1/2% per year... so 100 years from now
they will be 1/2 as good as they are now... (with today's
technology). "obsolete" merely means "not manufactured anymore"...
so big deal. Most items you own are obsolete: clothes you wear, TV
you own, stove, fridge, house, carpets, toaster, computer,
software... cars become obsolete (not made any more) at a max of 1
year after you've bought them... yet we don't hear perjorative
dismissive comments about cars do we?... so what's with the
dismissive comments about PV being "obsolete"?
I don't want subsidies for solar PV... I just want all energy sources
to pay for their true cost of energy production and energy generation
-- and then renewable energy economics will take care of themselves
thank you very much. My estimates are that solar PV will be the
least-cost electricity option for homeowners in Alberta within 2 to 4
years (and if I'm wrong then it is 6 years) -- all without subsidies
to solar PV. see also
<http://www1.eere.energy.gov/solar/pdfs/dpw_lushetsky.pdf>
PassivHaus is merely an organisational structure and training
programme that shows people where and how to become ultra-energy
efficient (which is great)... ultra energy efficiency has been
around since 1978 (with the Saskatchewan Conservation House in
Regina)... we've just not previously been interested in it because
we didn't care about the environment. Anyone can become ultra energy
efficient if they know what to do... PH is great, and so is NZE and
R2k and others.
Edmonton now has some 12 NZE houses under development by various
builders (shown below)... We look forward to anyone's comments on
them. You see some of my presentations on NZE homes at
<www.hme.ca/presentations> to see what we've learned with the first
three. My gut feel is that NZE-ready homes are the least-cost energy
option for homeowners in Alberta right now... I am working on the
economics analysis to vet this. NZE-ready is ultra energy efficient
plus solar PV ready. So why doesn't the PassiveHaus standard
incorporate PV-ready too? It should be a no-brainer. Talk about
"obsolete" houses? How about PH in 5 years without being PV
ready...! Imagine: being in a PH house where you can't put on a $20k
solar PV system to generate all your electrical energy (which isn't
"power") because the designers were feeling threatened by PV when it
was designed and so didn't accomodate it... ("threats" have to do
with our ego-states and not with technologies or costs)
Edmonton's NetZero Energy Houses
======================
Riverdale NetZero Energy Project (duplex), Habitat Studio and
Workshop ... completed and occupied by the homeowners
<www.riverdalenetzero.ca> <www.riverdalenetzero.ca/equilibrium>
<http://en.wikipedia.org/wiki/Zero_energy_building>
Mill Creek NetZero Energy Home, Habitat Studio and Workshop .....
completed and occupied by the homeowners
<www.greenedmonton.ca/MillCreekNetZeroHome>
Belgravia NetZero Energy Home, Habitat Studio and Workshop ...under
construction
Parkland NetZero Energy Home, Habitat Studio and Workshop ...under construction
Larch NetZero Energy Home, Habitat Studio and Workshop ...under development
Belgravia Green NetZero Energy Houses (3 separate houses), Effect
Homes, ...under construction
Ritchie Net Zero Ready house ...under construction
Sherwood Hills NetZero Energy Home ...under development
Shafraaz Kaba NetZero Energy Home ...under construction
Mike Turner NetZero Energy Home ...under construction
======================
Mike Holmes: very interesting comments. You might be interested in
one of his latest projects
<http://www.facebook.com/pages/Verde-in-Clearview-Ridge/174181109278587?ref=ts>
.
I welcome any comments and challenges to what I've written.
+Gordon Howell
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Gordon Howell, P.Eng.
Grid-Connected Solar-Electric Systems
Howell-Mayhew Engineering, Inc.
Edmonton
Phone : +1 780 484 0476
E-mail: ghowell at hme.ca
Web : www.hme.ca
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Date: Tue, 25 Jan 2011 19:12:23 -0500
>From: "Ross Elliott" <relliott at homesol.ca>
>To: "'jfstraube'" <jfstraube at gmail.com>, "'Green Building'"
> <greenbuilding at lists.bioenergylists.org>
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>Doh! I KNEW I was missing a mandatory! So there's four, not three.
>
>John, maybe I've been brainwashed by the Germans, but I kinda like that 0.6
>ACH50. According to the good Dr. Feist at that level of air tightness you
>won't get any hidden condensation problems (don't ask me why, I just believe
>everything I hear). My own place meets R-2000's 1.5 ACH50, yet in the last
>cold snap I discovered several frost balls on the outside of the foamboard
>(which would soon be hidden behind siding) where I've got some small air
>leaks. We've got a tract builder here in Ottawa who has built hundreds of
>homes in a row below 1.5 ACH50, so I don't think it's unreasonable to shoot
>for better on a custom green home.
>
>The "sophisticated computer program" we've been using for R-2000 since 1983
>actually doesn't work that well for high performance houses beyond the
>current R-2000 / ERS 80, there's going to be real problems getting them to
>NRCan's magical ERS 86 or 87 in the next version of R-2000 without using
>heat pumps everywhere. HOT2K just isn't that good at modeling great
>envelopes right now. It's also a "black box" where we just have to accept
>the results are accurately calculated, whereas the PHPP Excel spreadsheet
>allows you to see what's going on - not that it does a guy like me any good
>to know the formulas, but at least it's there for smarter people than me to
>quibble over.
>
>The Net Zero homes use exorbitantly expensive renewable energy systems to
>push them to zero, whereas in my humble opinion if they're not up around
>Passive House for their building envelope before they go for renewable then
>they're just buying energy to waste, at a lot higher cost than from the grid
>or pipeline. Talk about a science experiment. And if your total annual
>energy bill is under $1000 because you built a true energy efficient home,
>then putting $25,000 worth of PV on the roof seems like just a political
>statement, since those PV panels will be obsolete long before they pay for
>themselves (notwithstanding taxpayers covering the cost through incentive
>programs). But I really do appreciate your insights into where the tradeoffs
>should be in terms of cost, energy savings and carbon emissions, it's a
>conversation well worth continuing. Passive House may not be the answer to
>everything, but I think it's better than any of the alternatives currently
>available.
>
>But John, I really do have to agree with you about one thing. Mike Holmes is
>definitely not someone you want promoting anything to professional builders
>or renovators!
>
>Ross
>
>
>
>From: jfstraube [mailto:jfstraube at gmail.com]
>Sent: Tuesday, January 25, 2011 4:25 PM
>To: relliott at homesol.ca; Green Building
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>
>I think it is clear that you can build a PassivHaus standard home anywere.
>The question is, should you? More nuanced, the question is, "is the PH
>standard the optimal home for the location and purpose envisaged".
>
>CMHC has supported the construction of a whole bunch of Net Zero Energy
>houses across Canada, a more stringent energy standard than PH. This does
>not mean it is a good idea. However, the design teams are, under the target
>of Net Zero, allowed to trade off the cost of insulation, the cost of
>airtightness, and the cost of generation for their specific building and the
>climate in which it is built. PH is more dogmatic.
>
>I really like PHPP, but it is an Excel spreadsheet, not magic. R2000 home
>builders have been required to use a more sophisticated computer program and
>blower door test to verify their energy use compliance since forever (OK, 20
>years). They just have not set sufficiently low targets. I strongly agree
>that if PH can convince people to use a model to predict energy use and do a
>blower door test to confirm airtightness, then it will be a huge benefit.
>But one does not need to follow some of the dogmatic rules, like 0.6 at 50, to
>get a durable, healthy, afforable, and low energy building. There are
>numerous other tried and true methods. PH is just one set of numbers that
>one group chose.
>
>
>
>PS The PH standard DEFINITELY has a requirement of 0.6 ACH at 50 Pa. The 10%
>overheating is rarely listed.
>
>See for example Wikipeadia
>
>http://en.wikipedia.org/wiki/Passive_house#Requirements
>
>and
>
>Passive House USA
>
>http://www.passivehouse.us/passiveHouse/PassiveHouseInfo.html
>
>PSS If Mike Holmes is behind it, then PH just dropped in my estimation. Pop
>culture, yes, science and fact, NOT!
>
>
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>
>Message: 2
>Date: Tue, 25 Jan 2011 19:55:38 -0500
>From: "Ross Elliott" <relliott at homesol.ca>
>To: "'John O'Brien'" <john at boardom.ca>, "'Green Building'"
> <greenbuilding at lists.bioenergylists.org>
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>Message-ID: <000001cbbcf3$c229b860$467d2920$@ca>
>Content-Type: text/plain; charset="us-ascii"
>
>Final air test was 0.57 ACH50.
>
>
>
>Custom house prices depend on what you call "custom", I know people in the
>country who can build you a custom shack for way less. Anyone have an idea
>what tract homes go for on a SF basis? (the worst possible way to price a
>house, I might add - people buy a small crappy house, then move up into a
>bigger crappy house when their income goes up, rather than a better quality
>small house).
>
>
>
>Ground source heat pump was one of those things that could be termed
>"inappropriate technology", sort of overkill for such an efficient house,
>but seemed like a good idea back in the beginning (sure boosted that HOT2K
>EnerGuide rating, even though it's somewhat about the same efficiency
>burning coal in a power plant and sending it to a heat pump as just burning
>the coal in the house for heat instead). No problems with building
>inspectors to put XTPS under footings here in Ottawa, I think Chris used the
>Celfort 600 but I've seen 400 used with no problems.
>
>
>
>Ross Elliott
>
>
>
>From: boardom at gmail.com [mailto:boardom at gmail.com] On Behalf Of John O'Brien
>Sent: Tuesday, January 25, 2011 6:38 PM
>To: relliott at homesol.ca; Green Building
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>
>
>That's a pretty nice looking build Ross. Do you know what they came in as
>for their final blower door test reading. I'm curious about Chris's
>statement that to build a custom house in ottawa, you're looking at
>225-250$/sq ft. Am I the only one that considers that to be somewhat of
>reach of the average person.
>
>
>
>With their ground source system, were they able to find a unit that was
>sized small enough to meet the low energy demands?
>
>
>
>Very promising. Seems like they didn't have go too excessive on the subslab
>insulation compared to some of the other cold climate projects I've seen. Do
>you know if they had issues with the permit department with the foam under
>footings.
>
>
>
>J
>
>
>
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>------------------------------
>
>Message: 3
>Date: Tue, 25 Jan 2011 22:27:04 -0500
>From: jfstraube <jfstraube at gmail.com>
>To: <relliott at homesol.ca>
>Cc: 'Green Building' <greenbuilding at lists.bioenergylists.org>
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>I like 0.6 at 50 too, but it takes a lot of effort to achieve, and this
>may not always be justified. If I can get it, in cold Canada, I
>will take it every time. But if I only get to 0.9, then the house
>can still use the same energy as a PH with some other modifications.
>
>I also hear that the reason for the 0.6 is to limit condensation
>(would it not be nice to have this documented somewhere other than
>in interviews with Herr Feist?).
>However, if I design a wall properly, say placing half the
>insulation value outside of the wood framing, and use a ventilated
>space behind the cladding, it is essentially impossible to get
>condensation, even with, say, 2 ACH at 50. So if condensation control
>is the goal, we have the science and experience to support alternate
>methods of achieving that goal. The frost balls on the outside are
>not harming anything and we have many years of experience to show
>that R2000 airtightness has licked the condensation problems in
>climates much more severe than Germany.
>
>If energy saving is the issue of air tightness, then trade-offs
>between other components of the building should be allowed: it
>should be rolled into the energy target. There needs to be a limit
>to avoid comfort problems and IAQ problems: likely this is in the
>1.5 to 2.5 range depending on climate. But the energy and
>condensation reasons are not technically supportable.
>R-2000 air leakage limit is 1.5 at 50. Thousands have been
>built. We can do it. Thousands of homes have been built to
>0.6. We can do this. The question is, how much work and how worth it is it?
>
>This is the type of conversation that is needed. 0.0 ACH at 50 is nice
>and good, 0.5 is better than 0.6. Why 0.6 and not 0.7 or 1.0. If
>people are to follow the standard, there should be a good reason for
>the number or it should not be a hard requirement.
>
>Can you point me to more information on how HOT2K does not handle
>high performance homes? It was developed based on careful
>comparisons with real houses in the Canadian climate with Canadian
>occupants, and has worked well in my experience. I would like to
>see more of the problems you or others hace identified (and I bet
>NRCan would like to have some real info on this too) since I dont
>know of them. Many are using HOT3000 to get more accurate solar DHW
>and thermal mass feedback, although I would use WUFI PLUS (a German
>program with very good detail) to truly capture thermal mass. My
>retrofit house has an ERS rating of 86, which I achieved without a
>ground source heat pump, and with some changes I made this last
>year, I bet I would get 88 now.
>
>I like the open-source PHPP, but to make it this open they made a
>lot of simplifications and assumptions that limit its accuracy. It
>is fine in my books (I have my own set of spreadsheets I use, but
>they are based on hourly weather data, not monthly), but it is not
>correct to say it is more sophisticated, or more accurate, or more
>advanced (I have all claimed) than many other programs out there
>being used to design high performance houses. Check out the CEPHEUS
>100 house study: predictions varied around measured by +/-50% like
>most prediction programs.
>
>The Net Zero homes should not use "exorbitantly expensive renewable
>energy systems" to reach zero. Please look into them in some more
>detail. For example, some of them have R100 roofs and R70 walls and
>ACH around 0.5. They compared the cost of insulation or the cost of
>heat pumps or the cost of renewable energy systems and tried to
>choose the least cost path to optimization. Adding R20 of foam to
>an R20 foam slab (which seems common to some PH designs) is more
>expensive than using PV at market prices to save the same amount of
>energy that could be generated by the PV. Adding $10000 of
>insulation to say $250 PV can be wastefully deployed. Insulation
>and airtigtness and windows can be wastefully deployed. Todays PV
>systems will likely have the same lifespan or more than the glazing
>in the windows so I dont get the "obsolete" comment.
>
> I dont think PH's sole emphasis on insulation and airtightness is
> necessarily the right philosophy: nor do I believe Net Zero is the
> best way. I am sure that PH is not perfect and should be open to
> explaining its reasoning better than it does, and be more flexible
> to local climate and practise. You, Ross, are one of the level
> headed PH advocates who is willing to admit "PH is not the answer
> to everything", which makes this an enjoyable exchange.
>
>John
>
>On 2011-01-25, at 7:12 PM, Ross Elliott wrote:
> >
> > John, maybe I?ve been brainwashed by the Germans, but I kinda
> like that 0.6 ACH50. According to the good Dr. Feist at that level
> of air tightness you won?t get any hidden condensation problems
> (don?t ask me why, I just believe everything I hear). My own place
> meets R-2000?s 1.5 ACH50, yet in the last cold snap I discovered
> several frost balls on the outside of the foamboard (which would
> soon be hidden behind siding) where I?ve got some small air leaks.
> We?ve got a tract builder here in Ottawa who has built hundreds of
> homes in a row below 1.5 ACH50, so I don?t think it?s unreasonable
> to shoot for better on a custom green home.
> >
> > The ?sophisticated computer program? we?ve been using for R-2000
> since 1983 actually doesn?t work that well for high performance
> houses beyond the current R-2000 / ERS 80, there?s going to be real
> problems getting them to NRCan?s magical ERS 86 or 87 in the next
> version of R-2000 without using heat pumps everywhere. HOT2K just
> isn?t that good at modeling great envelopes right now. It?s also a
> ?black box? where we just have to accept the results are accurately
> calculated, whereas the PHPP Excel spreadsheet allows you to see
> what?s going on ? not that it does a guy like me any good to know
> the formulas, but at least it?s there for smarter people than me to
> quibble over.
> >
> > The Net Zero homes use exorbitantly expensive renewable energy
> systems to push them to zero, whereas in my humble opinion if
> they?re not up around Passive House for their building envelope
> before they go for renewable then they?re just buying energy to
> waste, at a lot higher cost than from the grid or pipeline. Talk
> about a science experiment? And if your total annual energy bill is
> under $1000 because you built a true energy efficient home, then
> putting $25,000 worth of PV on the roof seems like just a political
> statement, since those PV panels will be obsolete long before they
> pay for themselves (notwithstanding taxpayers covering the cost
> through incentive programs). But I really do appreciate your
> insights into where the tradeoffs should be in terms of cost,
> energy savings and carbon emissions, it?s a conversation well worth
> continuing. Passive House may not be the answer to everything, but
> I think it?s better than any of the alternatives currently available.
>
>-------------- next part --------------
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>
>------------------------------
>
>Message: 4
>Date: Tue, 25 Jan 2011 23:12:44 -0500
>From: Ross Elliott <homesol at bell.net>
>To: "'jfstraube'" <jfstraube at gmail.com>
>Cc: 'Green Building' <greenbuilding at lists.bioenergylists.org>
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>Message-ID: <BLU0-SMTP994C2E007EFC661A84A4AD3FF0 at phx.gbl>
>Content-Type: text/plain; charset="us-ascii"
>
>All excellent points, John.
>
>
>
>Concerning difficulty in air sealing to this level, I saw some great
>examples of using the structural sheathing layer as the air barrier when I
>was at the PH conference in Portland, OR this year, sure seems to be a
>better way than poly and tape and acoustic sealant for getting 3X tighter
>than R-2000. Freaks out some building officials though.
>
>
>
>I should clarify my issues with HOT2K to say the problem is really the
>EnerGuide Rating System, which is something NRCan is well aware of and in
>the process of changing. You might find that despite your best efforts it's
>pretty hard to get to an 88, but if you manage that extraordinary feat I bet
>you'll never get to an 89 without a heat pump (and what do these rating
>numbers really mean?). HOT2K is actually a pretty good modeling tool,
>particularly in General mode when you can over-ride the program-specific
>defaults and assumptions.
>
>
>
>Thanks for the great debate, I think we can both agree whatever gets more
>really efficient homes on the ground is a good thing.
>
>
>
>Ross Elliott
>
>
>
>
>
>From: jfstraube [mailto:jfstraube at gmail.com]
>Sent: Tuesday, January 25, 2011 10:27 PM
>To: relliott at homesol.ca
>Cc: 'Green Building'
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>
>
>I like 0.6 at 50 too, but it takes a lot of effort to achieve, and this may not
>always be justified. If I can get it, in cold Canada, I will take it every
>time. But if I only get to 0.9, then the house can still use the same energy
>as a PH with some other modifications.
>
>
>
>I also hear that the reason for the 0.6 is to limit condensation (would it
>not be nice to have this documented somewhere other than in interviews with
>Herr Feist?).
>
>However, if I design a wall properly, say placing half the insulation value
>outside of the wood framing, and use a ventilated space behind the cladding,
>it is essentially impossible to get condensation, even with, say, 2 ACH at 50.
>So if condensation control is the goal, we have the science and experience
>to support alternate methods of achieving that goal. The frost balls on the
>outside are not harming anything and we have many years of experience to
>show that R2000 airtightness has licked the condensation problems in
>climates much more severe than Germany.
>
>
>
>If energy saving is the issue of air tightness, then trade-offs between
>other components of the building should be allowed: it should be rolled into
>the energy target. There needs to be a limit to avoid comfort problems and
>IAQ problems: likely this is in the 1.5 to 2.5 range depending on climate.
>But the energy and condensation reasons are not technically supportable.
>
>R-2000 air leakage limit is 1.5 at 50. Thousands have been built. We can do
>it. Thousands of homes have been built to 0.6. We can do this. The
>question is, how much work and how worth it is it?
>
>
>
>This is the type of conversation that is needed. 0.0 ACH at 50 is nice and
>good, 0.5 is better than 0.6. Why 0.6 and not 0.7 or 1.0. If people are to
>follow the standard, there should be a good reason for the number or it
>should not be a hard requirement.
>
>
>
>Can you point me to more information on how HOT2K does not handle high
>performance homes? It was developed based on careful comparisons with real
>houses in the Canadian climate with Canadian occupants, and has worked well
>in my experience. I would like to see more of the problems you or others
>hace identified (and I bet NRCan would like to have some real info on this
>too) since I dont know of them. Many are using HOT3000 to get more accurate
>solar DHW and thermal mass feedback, although I would use WUFI PLUS (a
>German program with very good detail) to truly capture thermal mass. My
>retrofit house has an ERS rating of 86, which I achieved without a ground
>source heat pump, and with some changes I made this last year, I bet I would
>get 88 now.
>
>
>
>I like the open-source PHPP, but to make it this open they made a lot of
>simplifications and assumptions that limit its accuracy. It is fine in my
>books (I have my own set of spreadsheets I use, but they are based on hourly
>weather data, not monthly), but it is not correct to say it is more
>sophisticated, or more accurate, or more advanced (I have all claimed) than
>many other programs out there being used to design high performance houses.
>Check out the CEPHEUS 100 house study: predictions varied around measured by
>+/-50% like most prediction programs.
>
>
>
>The Net Zero homes should not use "exorbitantly expensive renewable energy
>systems" to reach zero. Please look into them in some more detail. For
>example, some of them have R100 roofs and R70 walls and ACH around 0.5.
>They compared the cost of insulation or the cost of heat pumps or the cost
>of renewable energy systems and tried to choose the least cost path to
>optimization. Adding R20 of foam to an R20 foam slab (which seems common to
>some PH designs) is more expensive than using PV at market prices to save
>the same amount of energy that could be generated by the PV. Adding $10000
>of insulation to say $250 PV can be wastefully deployed. Insulation and
>airtigtness and windows can be wastefully deployed. Todays PV systems will
>likely have the same lifespan or more than the glazing in the windows so I
>dont get the "obsolete" comment.
>
>
>
> I dont think PH's sole emphasis on insulation and airtightness is
>necessarily the right philosophy: nor do I believe Net Zero is the best way.
>I am sure that PH is not perfect and should be open to explaining its
>reasoning better than it does, and be more flexible to local climate and
>practise. You, Ross, are one of the level headed PH advocates who is
>willing to admit "PH is not the answer to everything", which makes this an
>enjoyable exchange.
>
>
>
>John
>
>
>
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>
>------------------------------
>
>Message: 5
>Date: Wed, 26 Jan 2011 08:35:00 -0500
>From: Frank Tettemer <frank at livingsol.com>
>To: Greenbuilding at bioenergylists.org
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>
> > Ross Elliott wrote:
>
> > Concerning difficulty in air sealing to this level, I saw some great
>examples of using the structural sheathing layer as the air barrier >
>when I was at the PH conference in Portland, OR this year, sure seems to
>be a better way than poly and tape and acoustic sealant > for getting 3X
>tighter than R-2000. Freaks out some building officials though.
>
>Firstly, congrats to Ross for the newly certified. It's a fine thing.
>
>John and Ross, this thread has been a fine untangling of mythical
>information, that has puzzled a hammer-head-builder like me for years
>now. I'm feeling pretty good now about some of my post-construction
>worries.
>Almost.
>
>I've been building energy efficient homes, using one out of the
>following three wall systems for the past decade, depending upon the
>customer's needs. It's either been plastered straw bale, or,
>double-frame 2x4 with cellulose blown in, or 2x4 frame with roxul and
>3"+ foil-backed ISO on the exterior. My post-construction observations
>have made me quite confident of the construction details for the first
>two systems, but gently un-nerved by the latter system.
>
>Concerning that system: I'm guessing, Ross, that your comment above
>relates to such a system. Could you elaborate a bit more about the
>details of construction for this?
>Mostly 'cause it freaks me out as well as the chief building officials!
>I've built with 2x4 frame, with polyisocyanurate panels added to the
>exterior, with seams taped with aluminum 3" tape, since the ISO became
>commercially available. So far, I haven't witnessed problems, but then
>again, I've not had to take any of the walls apart, to see what's going
>on inside them.
>
>My concern is, of course, the double vapour barrier: One on the inside
>("Super Six" plastic vapour barrier, all seams lapped and sealed with
>acoustiseal), and the second one, out past the inner insulation of R-14
>Roxul batts, (namely the foil-backed ISO).
>I've rationalized this set up by the thinking that I've placed the
>middle vapour barrier about 1/3 of the way through the wall's
>insulation, (R-14 inward, and R-21 or R-29 outward). And for this very
>reason, (as well as saving lumber), I've framed with 2x4 instead of 2x6,
>since a 2x6 wall would give me R-21 on the inside of the ISO sheathing.
>And to balance the equation, with a 2x6 frame, I'd need to have R-60 on
>the outside of the frame wall, which is more than most customers would
>care to pay for.
>In these wall sytems, I don't use plywood sheathing at all. I brace all
>frames, while lying on the deck, with metal T-shaped wind bracing, let
>into the wooden frames, to deal with racking. Seems to work fine. And
>with very long screws, fastening horizontal 1x4 strapping at 16" o.c., on
>the outside of the ISO, screwed into the vertical studs, I can then
>fasten vertical wooden siding, with a 3/4" air space, over the ISO.
>
>This "seems" to work fine, but is unsettling, 'cause it breaks the
>"rule" of having only one vapour barrier, and makes me tend to worry
>about mold growth inside of the Roxul, next to the ISO foil barrier.
>What do you all think about this seeming contradiction to the building
>code? Does it work, as it appears to? And if it does, why does it?
>
>Cheers,
>Frank
>
>Frank Tettemer
>Living Sol ~ Building and Design
>www.livingsol.com
>613 756 3884
>
>
>
>
>------------------------------
>
>Message: 6
>Date: Wed, 26 Jan 2011 09:55:10 -0500
>From: "nick pine" <nick at early.com>
>To: <greenbuilding at lists.bioenergylists.org>
>Subject: [Greenbuilding] Tweaking a band sealer
>
>Marcus Sadler and his crew have made 34 4'x8' glazing panels with 2
>10 mil HP92W polycarbonate films with a butyl rubber tape seal in
>a 2x2 sandwich with a Schraeder tire valve. They are gently inflated
>with propane now for leak testing with a sensitive gas leak detector.
>They will be inflated with welding argon soon. Each panel required
>about 12 person-hours of labor...
>
>We hope to reduce the labor content with a $400 tabletop Chinese
>band-sealing "fusing machine" with a 500 watt heater and a digital
>temperature control and 2 Teflon belts with a speed control:
>http://www.simplesealers.com/fr900-horizontal-heat-sealer.html
>
>It's intended for sealing plastic pouches which pass between 2 offset
>rollers. The 1/4" Teflon belts drag the edges of 2 plastic films
>between 2 1/2"x1/2"x4" brass heater bars with a 0-300C bang-bang
>temperature controller (polycarbonate melts at 267C.) Then the films
>pass between 2 brass cooler bars about 3" long and 2 more unpowered
>compression rollers with an adjustable spring.
>
>Sometimes we get good results, with an airtight seal that cannot be
>pulled apart, but the results vary a lot. The DC motor stopped once
>in a while and the machine went dead and wouldn't start again until
>we turned the power switch off and on. And it slowed when the heater
>turned on and the voltage at the end of the tiny power cord wires
>dropped from 120 to 114 V, so we rewired the cord and the rest of
>the machine and fixed a few bad solder joints.
>
>Now it seems that most of the variability comes from the cooler bars,
>which are not required for polycarbonate. They are only heated when
>hot plastic film passes between them, so their temperature increases
>during long seams (we would like to make 8 foot seams.) We plan to
>replace them with another $39 set of heater bars and another $25
>temperature controller, which seems doable, although it requires
>shortening the new heater bars, which are hollow brass boxes with
>uncoated wirewound resistors inside.
>
>The films also tend to pucker a lot between the 1/2" seam and
>the edges about an inch further outboard, and the seam smears along
>its length. Powering some of the unpowered pairs of rollers and
>making them pinch the films at right angles instead of offsetting
>them might make for a nicer seam.
>
>Nick
>
>
>
>------------------------------
>
>Message: 7
>Date: Wed, 26 Jan 2011 10:31:43 -0400
>From: Shawna Henderson <s_henderson at me.com>
>To: relliott at homesol.ca, Green Building
> <greenbuilding at lists.bioenergylists.org>
>Subject: Re: [Greenbuilding] first certified Passive House in Canada
>
>Hey Ross and John,
>
>Here in NS, we have several small production builders who consistently
>come in at <1 ACH at 50, Keith Sawlor hit 0.29 (I personally did that
>test, about 15 years ago!!). On all of our custom design jobs, 0.5ACH
>@ 50 is the target on our bid documents. While not all builders hit
>that, they are consistently coming in at less than 1 and some are bang
>on, because they have long-standing crews who can do the air sealing
>work. Ross, I'm with you on the NZE house $25,000 PV extravaganza,
>which might make sense where there is a decent FIT, like ON, but here
>in NS, where ComFIT comes into play April 1, there is still no real
>business case for it (ie, ROI sucks). We ensure that the design and
>planning allows for 3 to 7 kW PV on the roof and with conduit (not
>wiring) in place and wall space in the mechanical area for inverter
>and controls, roof mount and any extra bracing etc in place as
>homeowner dictates. When it's affordable/cost-effective, homeowner can
>have it installed.
>
>I agree with John on the issues around the energy modelling, and that
>a set of dogmatic rules leads us right back to the one-size-fits-all
>approach, which leads us right back to the problem of large tract
>builders and 1,000s of spec homes in GTA every year that are not
>meeting the +20-year-old R2000 standard, but are building to a one-
>size-fits-all approach, just using a different set of dogmatic rules
>driven by a different set of requirements ($/sf vs W/sf).
>
>Cheers from mighty chilly Halifax
>
>Shawna
>
>On 25-Jan-11, at 8:12 PM, Ross Elliott wrote:
>
> > Doh! I KNEW I was missing a mandatory! So there?s four, not three.
> >
> > John, maybe I?ve been brainwashed by the Germans, but I kinda like
> > that 0.6 ACH50. According to the good Dr. Feist at that level of air
> > tightness you won?t get any hidden condensation problems (don?t ask
> > me why, I just believe everything I hear). My own place meets
> > R-2000?s 1.5 ACH50, yet in the last cold snap I discovered several
> > frost balls on the outside of the foamboard (which would soon be
> > hidden behind siding) where I?ve got some small air leaks. We?ve got
> > a tract builder here in Ottawa who has built hundreds of homes in a
> > row below 1.5 ACH50, so I don?t think it?s unreasonable to shoot for
> > better on a custom green home.
> >
> > The ?sophisticated computer program? we?ve been using for R-2000
> > since 1983 actually doesn?t work that well for high performance
> > houses beyond the current R-2000 / ERS 80, there?s going to be real
> > problems getting them to NRCan?s magical ERS 86 or 87 in the next
> > version of R-2000 without using heat pumps everywhere. HOT2K just
> > isn?t that good at modeling great envelopes right now. It?s also a
> > ?black box? where we just have to accept the results are accurately
> > calculated, whereas the PHPP Excel spreadsheet allows you to see
> > what?s going on ? not that it does a guy like me any good to know
> > the formulas, but at least it?s there for smarter people than me to
> > quibble over.
> >
> > The Net Zero homes use exorbitantly expensive renewable energy
> > systems to push them to zero, whereas in my humble opinion if
> > they?re not up around Passive House for their building envelope
> > before they go for renewable then they?re just buying energy to
> > waste, at a lot higher cost than from the grid or pipeline. Talk
> > about a science experiment? And if your total annual energy bill is
> > under $1000 because you built a true energy efficient home, then
> > putting $25,000 worth of PV on the roof seems like just a political
> > statement, since those PV panels will be obsolete long before they
> > pay for themselves (notwithstanding taxpayers covering the cost
> > through incentive programs). But I really do appreciate your
> > insights into where the tradeoffs should be in terms of cost, energy
> > savings and carbon emissions, it?s a conversation well worth
> > continuing. Passive House may not be the answer to everything, but I
> > think it?s better than any of the alternatives currently available.
> >
> > But John, I really do have to agree with you about one thing. Mike
> > Holmes is definitely not someone you want promoting anything to
> > professional builders or renovators!
> >
> > Ross
> >
> > From: jfstraube [mailto:jfstraube at gmail.com]
> > Sent: Tuesday, January 25, 2011 4:25 PM
> > To: relliott at homesol.ca; Green Building
> > Subject: Re: [Greenbuilding] first certified Passive House in Canada
> >
> > I think it is clear that you can build a PassivHaus standard home
> > anywere. The question is, should you? More nuanced, the question
> > is, "is the PH standard the optimal home for the location and
> > purpose envisaged".
> > CMHC has supported the construction of a whole bunch of Net Zero
> > Energy houses across Canada, a more stringent energy standard than
> > PH. This does not mean it is a good idea. However, the design teams
> > are, under the target of Net Zero, allowed to trade off the cost of
> > insulation, the cost of airtightness, and the cost of generation for
> > their specific building and the climate in which it is built. PH is
> > more dogmatic.
> >
> > I really like PHPP, but it is an Excel spreadsheet, not magic.
> > R2000 home builders have been required to use a more sophisticated
> > computer program and blower door test to verify their energy use
> > compliance since forever (OK, 20 years). They just have not set
> > sufficiently low targets. I strongly agree that if PH can convince
> > people to use a model to predict energy use and do a blower door
> > test to confirm airtightness, then it will be a huge benefit. But
> > one does not need to follow some of the dogmatic rules, like 0.6 at 50,
> > to get a durable, healthy, afforable, and low energy building.
> > There are numerous other tried and true methods. PH is just one set
> > of numbers that one group chose.
> >
> > PS The PH standard DEFINITELY has a requirement of 0.6 ACH at 50 Pa.
> > The 10% overheating is rarely listed.
> > See for example Wikipeadia
> > http://en.wikipedia.org/wiki/Passive_house#Requirements
> > and
> > Passive House USA
> > http://www.passivehouse.us/passiveHouse/PassiveHouseInfo.html
> >
> >
> > PSS If Mike Holmes is behind it, then PH just dropped in my
> > estimation. Pop culture, yes, science and fact, NOT!
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