Posted By Roberth on 09 Mar 2012 01:00 AM
It appears that he did not go anywhere near a passive house/net zero design. His walls dont ever approach R40. Dont know if he went 2x6 or 2x4 but he has 2 inches of foam. Spray foam in rim joist. With good marketing he should be able to get a little more for his house. I would liken his house to a car that gets a little better milage and not a hybrid.

A home is like a car, you drive it off the lot and its worth less. Same thing happens with homes. Top that off in that econmy is depressed and its a rough time to sell.

A home was always (until 2008) an appreciating asset, cars were always depreciating assets. I agree, the economy is depressed and homes have taken a huge hit. The problem is that most tract homes are far from good energy builds and unfortunately they make up for 95% of homes built and sold. Energy builds are usually custom homes, which is a very niche market.

How would one get R-40 in a wood framed home?

I assume 4"-5" of closed spray foam and then 2" of EPS on the exterior walls. That would be around R34 - R39 but you still have the thermal bridging to factor in, as walls studs count for 30% of wall space area, and a 2x6 has a R-value of R5. Unless one staggered the wall studs. All of this stuff is still expensive. Depending where you live, it is not uncommon for it to run $4 a square foot. So a 1,500 sqft home with 8' walls, to spray foam the interior walls will run you $13K. The stuff works, just stay away from any foam containing soy or plant products, there has been a lot of problems with them.

Posted By Lbear on 09 Mar 2012 01:54 AM

Posted By Roberth on 09 Mar 2012 01:00 AM
It appears that he did not go anywhere near a passive house/net zero design. His walls dont ever approach R40. Dont know if he went 2x6 or 2x4 but he has 2 inches of foam. Spray foam in rim joist. With good marketing he should be able to get a little more for his house. I would liken his house to a car that gets a little better milage and not a hybrid.

A home is like a car, you drive it off the lot and its worth less. Same thing happens with homes. Top that off in that econmy is depressed and its a rough time to sell.

A home was always (until 2008) an appreciating asset, cars were always depreciating assets. I agree, the economy is depressed and homes have taken a huge hit. The problem is that most tract homes are far from good energy builds and unfortunately they make up for 95% of homes built and sold. Energy builds are usually custom homes, which is a very niche market.

How would one get R-40 in a wood framed home?

I assume 4"-5" of closed spray foam and then 2" of EPS on the exterior walls. That would be around R34 - R39 but you still have the thermal bridging to factor in, as walls studs count for 30% of wall space area, and a 2x6 has a R-value of R5. Unless one staggered the wall studs. All of this stuff is still expensive. Depending where you live, it is not uncommon for it to run $4 a square foot. So a 1,500 sqft home with 8' walls, to spray foam the interior walls will run you $13K. The stuff works, just stay away from any foam containing soy or plant products, there has been a lot of problems with them.

With a 20% framing fraction and a better than industry-average R6.9/inch closed cell foam, and 2" of EPS (R8), wood sheathing & siding + 5/8" gypsum (~R1-ish, if you add all 3), you get a whole wall R value of about R25.

With the same 20% framing fraction and R3.6/inch dense-packed cellulose cavity fill and two layers of 2" polyiso (4" total) you get a whole wall R of ~ R38.  A full cavity fill of cellulose is cheaper than 2" of exterior EPS, and 4" of iso is comparable to (usually cheaper than) 4" of 2lb foam, let alone 5".  It's literally 50%+ higher R, for significantly less money.  

It's better to use the difference in cash t do a blower door and theatre-smoke machine  test before siding and sheet rock go up and NAIL that air sealing to near-perfection, and you'd still probably have some cash left over.

The moral of the story: closed cell foam as cavity fill is a ridiculous waste of money, since it's performance gets totally undercut by the thermal bridging that dominates the heat transfer.  Better to use the cheap stuff in in the cavity, and save the foam budget for the exterior, where you get the full benefit of the foam-R as a thermal break over the framing, not just center-cavity.

A 1" flash-foam of ccSPF is sufficient for air-sealing the cavity, but doesn't address all air-sealing issues with wall, but it also creates a non-wicking semi-permeable condensing surface, and protects the sheathing from interior moisture drives. In some instances there's going to be a rational for a flash'n'fill using cc foam. But a ful (or nearly full) fill? Fuggedaboudit! You're not doing your pocketbook or the planet any favors with that approach.  The blowing agents of closed cell polyurethanes have a higher lifecycle greenhouse gas potential than it offsets by lower heating/cooling costs when looking at anything over 1.5-2" too. (It's on the order of 100x more destructive than the pentane used for blowing EPS or iso.)  Used for air sealing and condensation control, sure- it's hard to beat ccSPF, but if it can be economically designed-out, it should be.  As raw insulation it the most expensive R you can buy except for aerogel.

A 30% framing fraction would be a brain-dead egregious waste of timber- a truly bad design.  "Typical" housing where thermal bridging gets ignored ends up in the ~25% range, and it's not hard to hit 20% with a conscious design approach.  Rather than random wall lengths and random window & door placements & sizes adding to the framing fraction minimizing narrow cavities and extra studs/headers, and using advance-framing corners is pretty straightforward stuff.  If you went the whole 9 yards for OVE/advanced framing approach it's possible to hit 16% framing fractions using 24" o.c. stud spacing and only single-plates, aligning raftes over studs, etc,  but that can create wall-flatness quality issues.  I tend to use 20% as a readily achievable design goal when looking at new construction, custom design-  I'd have to work at it to hit 30%, but I s'pose anything's possible, eh?  :-)

Building green and/or driving green should be about lowering one's footprint and not about saving money or ROI. If the Chevy Volt only has a range of 25 miles, but if your commute is only 25 miles round trip or less, then it would be a wise choice. Not for money's sake, but for the environment. To some, dropping another 10 grand or so on a vehicle is no big deal if they feel they are making a difference. Same thing goes with the Prius. There's really no "equivalent" vehicle to compare that to. There's a ton of technology that goes into the Prius. I surprised they sell it for less than 30K. An now with the plug-in prius . . . if you can afford it, you should do it for mother earth's sake.

Now, of course, I'm a huge hypocrite. My two vehicles include a 99' Tahoe and a 76' Jeep . . . .

Posted By jeepster on 09 Mar 2012 11:03 PM
Building green and/or driving green should be about lowering one's footprint and not about saving money or ROI. If the Chevy Volt only has a range of 25 miles, but if your commute is only 25 miles round trip or less, then it would be a wise choice. Not for money's sake, but for the environment. To some, dropping another 10 grand or so on a vehicle is no big deal if they feel they are making a difference. Same thing goes with the Prius. There's really no "equivalent" vehicle to compare that to. There's a ton of technology that goes into the Prius. I surprised they sell it for less than 30K. An now with the plug-in prius . . . if you can afford it, you should do it for mother earth's sake.

Now, of course, I'm a huge hypocrite. My two vehicles include a 99' Tahoe and a 76' Jeep . . . .

Try running that line past a married family trying to raise 3 kids and put food on the table. Go ahead and tell them that what matters is, "lowering one's footprint and not about saving money." When it comes to family vs. environment, family always wins. A lot of the environmental stuff is about feel good and bragging rights, to the middle class family trying to make ends meet, doing "green" is fodder for the forums.


Not until the green stuff becomes affordable, it will never be mainstream.

Posted By Dana1 on 09 Mar 2012 06:18 PM

With the same 20% framing fraction and R3.6/inch dense-packed cellulose cavity fill and two layers of 2" polyiso (4" total) you get a whole wall R of ~ R38.  A full cavity fill of cellulose is cheaper than 2" of exterior EPS, and 4" of iso is comparable to (usually cheaper than) 4" of 2lb foam, let alone 5".  It's literally 50%+ higher R, for significantly less money.  

It's better to use the difference in cash t do a blower door and theatre-smoke machine  test before siding and sheet rock go up and NAIL that air sealing to near-perfection, and you'd still probably have some cash left over.

The moral of the story: closed cell foam as cavity fill is a ridiculous waste of money, since it's performance gets totally undercut by the thermal bridging that dominates the heat transfer.  Better to use the cheap stuff in in the cavity, and save the foam budget for the exterior, where you get the full benefit of the foam-R as a thermal break over the framing, not just center-cavity.

A 1" flash-foam of ccSPF is sufficient for air-sealing the cavity, but doesn't address all air-sealing issues with wall, but it also creates a non-wicking semi-permeable condensing surface, and protects the sheathing from interior moisture drives. In some instances there's going to be a rational for a flash'n'fill using cc foam. But a ful (or nearly full) fill? Fuggedaboudit! You're not doing your pocketbook or the planet any favors with that approach.  The blowing agents of closed cell polyurethanes have a higher lifecycle greenhouse gas potential than it offsets by lower heating/cooling costs when looking at anything over 1.5-2" too. (It's on the order of 100x more destructive than the pentane used for blowing EPS or iso.)  Used for air sealing and condensation control, sure- it's hard to beat ccSPF, but if it can be economically designed-out, it should be.  As raw insulation it the most expensive R you can buy except for aerogel.

A 30% framing fraction would be a brain-dead egregious waste of timber- a truly bad design.  "Typical" housing where thermal bridging gets ignored ends up in the ~25% range, and it's not hard to hit 20% with a conscious design approach.  Rather than random wall lengths and random window & door placements & sizes adding to the framing fraction minimizing narrow cavities and extra studs/headers, and using advance-framing corners is pretty straightforward stuff.  If you went the whole 9 yards for OVE/advanced framing approach it's possible to hit 16% framing fractions using 24" o.c. stud spacing and only single-plates, aligning raftes over studs, etc,  but that can create wall-flatness quality issues.  I tend to use 20% as a readily achievable design goal when looking at new construction, custom design-  I'd have to work at it to hit 30%, but I s'pose anything's possible, eh?  :-)

Out here the homes have a 30% framing for strength. When you have a 4x6 window span, that area will get triple framing around the window to support the window. Using 2x6 @ 16" o.c. is code for wind/seismic loads and 2 story homes. I have not seen a new home with 20% framing, it would not pass code out here.

Their are problems with cellulose. To try and keep rodents from nesting in the walls filled with cellulose, companies soak the cellulose with chemicals like boric acid. The additional components in cellulose include binders, formaldehyde, fire-retardants, ammonium sulfate, sulfuric acid, borax, boric acid, and other chemicals. The New England Journal of Medicine published a review on health effects of cellulose insulation reported that "the fire retarding chemicals used to recycle cellulose insulation is potentially carcinogenic. There is A LOT of off-gassing in cellulose.

Lbear,

You assume that everyone in the world is living paycheck to paycheck.  Many people/families can "afford" to upgrade to things that have a lower footprint.  Just like many will spend MORE to buy American.  I'm one of those as well.  I'm not rich.  My wife and I are both raising two kids on a teacher's salary.  But, I've built our house using ICF and I'm the only one in the neighborhood to put in geo.  I know the return won't be there.  I just feel it's the right thing to do. 

So, long and short, I can run that line across 10 families and I'd guess all of them THAT CAN AFFORD IT, will do it.  If not, shame on them.

  "the fire retarding chemicals used to recycle cellulose insulation is potentially carcinogenic. There is A LOT of off-gassing in cellulose.

The quote above is misleading.  "chemicals used to recycle cellulose insulation."  Who's recycling cellulose insulation?  And why does this matter to the home owner. 

I would not say that there is A LOT of off-gassing.  The packages sold around here state Formaldehyde free. 

If I were to venture a guess, since that's what you are really doing, and I won't use words like A LOT, ALWAYS, or NEVER, but the off-gassing from carpet, furniture, and stains/paints, to be way worse for your health than the insulation in your attic and sealed in your walls.

When in doubt, install an ERV.

just stay away from any foam containing soy or plant products, there has been a lot of problems with them.

What sort of problems?

Posted By jeepster on 10 Mar 2012 08:53 AM
The quote above is misleading.  "chemicals used to recycle cellulose insulation."  Who's recycling cellulose insulation?  And why does this matter to the home owner. 

I would not say that there is A LOT of off-gassing.  The packages sold around here state Formaldehyde free. 

If I were to venture a guess, since that's what you are really doing, and I won't use words like A LOT, ALWAYS, or NEVER, but the off-gassing from carpet, furniture, and stains/paints, to be way worse for your health than the insulation in your attic and sealed in your walls.

When in doubt, install an ERV.

It was a clerical error, I meant to say that chemicals used in cellulose insulation, which is composed of 80% recycled materials (newspapers).

No guessing here, there is scientific data to back this. Do a Google search.

Posted By Lbear on 10 Mar 2012 03:31 PM
It was a clerical error, I meant to say that chemicals used in cellulose insulation, which is composed of 80% recycled materials (newspapers).

No guessing here, there is scientific data to back this. Do a Google search.

If there is scientific data to back up your bold statements, then provide references so that we can all evaluate your sources. 

Posted By Lee Dodge on 10 Mar 2012 04:49 PM

If there is scientific data to back up your bold statements, then provide references so that we can all evaluate your sources. 

Sure, here you go...

Health Risks of Cellulose

NTP Study

Cellulose Drawbacks


there are more but that is homework for you.

Posted By Lbear on 10 Mar 2012 05:09 PM

Posted By Lee Dodge on 10 Mar 2012 04:49 PM

If there is scientific data to back up your bold statements, then provide references so that we can all evaluate your sources. 

Sure, here you go...

Health Risks of Cellulose

NTP Study

Cellulose Drawbacks


there are more but that is homework for you.

The NTP study listed above is the only one that should be taken seriously.  The first link is from a spray foam installer, so there's obvious bias.  Talk to a cellulose guy and they spout out all the health hazards of spray foam. 

The last link is another broad statement from someone that wanted to create a website.

The NTP study addressed health concerns of installers.  I don't think you'll find any insulation installer that doesn't have health issues if they don't wear the proper PPE.  The NTP study really only concluded that there needs to be more studies.  That was back in 06' also, before Formaldehyde was put on the black list.

Posted By Lbear on 10 Mar 2012 05:09 PM

Posted By Lee Dodge on 10 Mar 2012 04:49 PM

If there is scientific data to back up your bold statements, then provide references so that we can all evaluate your sources. 

Sure, here you go...

Health Risks of Cellulose

NTP Study

Cellulose Drawbacks


there are more but that is homework for you.

The first link is to a company that installs spray foam insulation.  Two of the three links they provide are invalid and most likely don't support their assumptions.  The third link says exactly the same thing as the spray foam companies page and uses the two invalid links as references.  'nuf said.

The second link above relates to exposure of workers installing cellulose insulation.  The results of that study don't support your assertions.  From the study: 

Results
Of the cellulose insulation particles examined by the generator, less than 0.1% were of the size that were respirable by the lung. Similarly at the worksites, the amounts of respirable size dusts were typically low. While workers had occasional eye or mucous membrane irritation, there was little evidence of any lower respiratory health conditions.

Conclusions
We conclude that because almost all of the generated cellulose insulation particles are not respirable, additional studies of cellulose insulation in laboratory animals are not needed.

The third link is little more than an opinion article - all fluff with no supporting references.

Posted By Lbear on 10 Mar 2012 03:31 PM

...It was a clerical error, I meant to say that chemicals used in cellulose insulation, which is composed of 80% recycled materials (newspapers).

No you didn't.  All you did was cut-and-paste from this spray foam insulation company's page that you linked to:

http://insulationcleaners.com/the-h...nsulation/

Quote from that page:

The New England Journal of Medicine published a review on health effects of cellulose insulation reported that “the fire retarding chemicals used to recycle cellulose insulation could be potentially carcinogenic (cancer causing)”.

The point is that all insulation methods have their drawbacks, there is no perfect insulation method. Some are better than others and each one has its pros and cons. One can build a wood framed home and take measures to make it energy efficient, while not inexpensive to do, it can be done on a custom built home but it will raise the costs. Will the homeowner see a ROI if they sell their home? Market show the answer is most likely not. As reiterated by the OP.

Posted By Lbear on 10 Mar 2012 12:09 AM

Their are problems with cellulose. To try and keep rodents from nesting in the walls filled with cellulose, companies soak the cellulose with chemicals like boric acid. The additional components in cellulose include binders, formaldehyde, fire-retardants, ammonium sulfate, sulfuric acid, borax, boric acid, and other chemicals. The New England Journal of Medicine published a review on health effects of cellulose insulation reported that "the fire retarding chemicals used to recycle cellulose insulation is potentially carcinogenic. There is A LOT of off-gassing in cellulose.

When asked to provide references to back up these statements, you kindly provided three.  The most authoritative reference was from the National Institute of Health's National Toxicology Program, which indeed is a very reputable source, and specifically the following report, http://ntp.niehs.nih.gov/ntp/htdocs...74_rev.pdf. 

This report addresses potential exposure problems in installing cellulose, not living in a house with cellulose, as shown in this quote from the summary of that report (bold text by this author):
"Background:  Cellulose insulation is produced mainly from recycled newspapers, which are shredded and treated with fire-retardant chemicals. The materials are installed by blowing, which creates a potential hazard to workers. We studied the physical and chemical properties of cellulose insulation aerosols and surveyed several workplace exposure conditions to determine if such a hazard exists."   

And what did the NIH report find?
"Results:  Of the cellulose insulation particles examined by the generator, less than 0.1% were of the size that were respirable by the lung. Similarly at the worksites, the amounts of respirable size dusts were typically low. While workers had occasional eye or mucous membrane irritation, there was little evidence of any lower respiratory health conditions."

"Conclusions:  We conclude that because almost all of the generated cellulose insulation particles are not respirable, additional studies of cellulose insulation in laboratory animals are not needed." 

A second reference that you provided was from Buzzle.com (http://www.buzzle.com/articles/cell...blems.html), a collection of non-refereed contributions from whoever wants to express an opinion.  In this case, a lawyer named Sonia Nair, better known for her article on "How to Potty Train a Hamster" (http://www.buzzle.com/articles/how-...mster.html), stated in her article on cellulose, "You cannot rule out cellulose insulation health problems, as it contains certain chemicals. These chemicals like those present in inks and dyes of newspaper and added fire retardants, may cause allergic reactions in sensitive people. Even the dust that comes out of the insulation can be a health concern."  This is NOT what I would consider an authoritative scientific analysis of the health effects of cellulose. 

Your third reference (http://insulationcleaners.com/the-h...nsulation/) was to a company called Insulation Cleaners selling their services to remove insulation and install spray foam insulation.  Again this in not what I would consider an unbiased, useful, scientific reference.     

So the one credible reference that you provided concluded that workplace exposure to cellulose was not a significant enough problem to conduct further testing in laboratory animals.  Based on that reference, and having worked with fiberglass on numerous occasions with resulting itching problems on my skin, and having lived through the nightmare in the 1970's of spray foam insulation with formaldehyde that sometimes did not cure properly with the result that walls had to be torn out and the foam removed, I feel much better about using cellulose.

Cellulose is one of a palette of insulation materials - and a broader palette of building materials. No building material is perfect or without it's limitations/hazards. The goal in building is to combine the materials into a building system so that the strength of the system overcomes the weaknesses of each individual material. That said cellulose has a lot going for it - cheap per R, hygric buffer, packs to a pretty good air seal, recycled content. It also has some limitations, messy install, settling, and the included chemicals under debate. I'm an architect and not an MD but I've read a lot of MSDS sheets in my day and the MSDS on cellulose is pretty benign (see for example http://www.greenfiber.com/images/technicaldocuments/81201115908PMMS-6.4-060%20Rev%20C%20Stabilized%20Borate%20Formula.pdf) I agree that the NIH report noted is the only credible source an seems to address risks to installers (as does the MSDS) and the risks noted by both seem pretty minimal compared to many other building products out there. Would I install cellulose without proper eye and respiratory PPE? No. Would I have 30 years ago when I was a young and enthusiastic but foolish DIY'er - of course. With proper use and protective measures my take is that cellulose is a fine material for both installer and occupant. If there's real info out there that says otherwise I'd like to see it as cellulose is a part of several building systems I'm planning now....

Yes and No. First off I think you need to find a Realtor who specializes in specialty homes. Second if you took the time to put your insulation and improvement recipts and prove what you are claiming as well as copies of your before and after utility bills then I think that goes along ways and your buyers more receptive.

Who hasn't watched the news and heard of $5 gas? Utilities will soon double what they are today. Third, we are in a weak real estate market which I think has more of a negative effect than not getting a tiny bit (5%) more for your home.

I think this highlights the importance of owners getting multiple bids on each improvement, becoming aware of and finding the best and most effective sources of improvements. Reading up alot and not taking the first contractors word on everything.

I was able to super insulate my house for $7500 on a home that is likely worth $200-250k. estimate savings on energy of about 50%. We replaced insulation with tight Closed cell foam, removed any wind drift and miniaturized some old large windows and took others out all together, put Trees on south side windows so that they bloom and block sun in the summer and in the winter the light gets through and heats that side of the house. That was all my low lying fruit so to speak. Then I spent another $4k upgrading my propane and inefficient a/c to a Geothermal Heat-pump (self installed probably saved half price). The combined payback is about 4 years. I am documenting every change, as well as utilities to show a prospective buyer...but I plan to die in this house.....still stuff happens.

Try to hold on for a year or two and see if the market gets a little better then you can probably get more of your money back, as well as continue saving monthly utilities to get use out of your investment. I think I'd rather rent the home than take a loss on it.

Good Luck

Lbear:   At 30% framing fraction a 2x6 wall with 5" of  R6.9/inch ccSPF  (can't go full-depth- it's too hard to trim flush) ends up with a whole wall R of ~R13.5.

The same wall with R3.6/inch cellulose at 5.5" ends up at R12.1.

That's a very expensive extra R1.4 compared to putting 3/8" of XPS underlayment (~R1.9) under the siding of the cellulose insulated wall, eh?

The lifecycle greenhouse gas potential of the 5" ccSPF blown with HFC245 is several times greater than the energy sources that it offset.   It will be getting somewhat better soon, but even the newer blowing agents are less enviro-friendly than the pentane used for blowing rigid iso.

Rodents nesting in cellulose- even low-density open-blown attic stuff is actually pretty rare, (unlike low-and mid density fiberglass.)  The fire retardents used are eye and lung irritants.  There is no sulfuric acid or formaldehyde- the MOST toxic stuff in it is the printers-inks (being primarly recycled newsprint) which it the only material in cellulose that outgasses.  (Unlike ccSPF, which outgasses the HFC blowning agents for decades.) It's important (but not difficult) to avoid cellulose products with sulfate fire retardents, since those become fairly corrosive to metals should it ever become wet, but there are several vendors that only use borates. Borates are relatively benign to humans, used in everything from soaps to cosmetics and medicines inconcentrations much higher than could be ingested by living in a cellulose insulated house (even if you slept buried in the attic cellulose!) but it destroys the gut flora of termites/ants/bees and other wood-boring insects, rendering the digestion of wood impossible of the host insect, killing them.

What is a 4x6 window span?