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Memo to Residential Insulation Stakeholders (PDF 138 KB), Oct. 2006
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Posted By: P. Marc LaFrance from US Department Of Energy
October 12, 2006 3:24 PM
Dear Stakeholders, DOE through its Oak Ridge National Laboratory will be conducting a new analysis regarding the recommended residential insulation levels. Please see the attached ORNL letter that requests your comments. Please post your comments below so that all stakeholders can see your thoughts and can respond if desired. Thank You Marc LaFrance US DOE Technology Development Manager 202-586-9142
Replied By: from
19 - Oct - 2006 2:19
PM ICF and SIPS...
This is a posting for Mr. Whalen, if other people have problems posting information I will help you, but please try to make your own postings.
Thanks, Marc LaFrance
We received the press release from ORNL (André Desjarlais) indicating that the DOE Insulation Fact Sheet is scheduled to be updated in early FY07. The press release indicated that you would be the contact person for comments and suggested revisions.
The existing fact sheet provides contact information for ICFA and SIPA, but the documents do not include any reference to ICF or SIP systems. I note that the press release from André indicated that every possible insulation level was considered and the lowest life-cycle cost is recommended. Is there any intention to include consideration of these types of building systems in the updated analysis and final document?
I would be interested in any information you can provide on the above.
Jim Whalen, P. Eng.
Technical Marketing Manager
Replied By: from
20 - Oct - 2006 7:41 AM
Provisions for mass envelope....
To: Therese Stovall
Oak Ridge National Laboratory
According to the October 12 memorandum from Andre Desjarlais.
it appears that calculations for the proposed 2007 update of the DOE Insulation fact sheet will make simple adjustments for differences between one-dimensional results and whole-house behavior.
How do the proposed algorithms and the simple adjustments account for mass, or take mass wall construction into consideration?
Michael F. Werner, P.E., LEED A.P.
Engineering Projects Manager
National Concrete Masonry Association
13750 Sunrise Valley Drive
Herndon, VA 20171
703 713 1900
Replied By: Therese Stovall from Oak Ridge National Lab
01 - Nov - 2006 3:29 PM
Response to Whalen...
ORNL will consider ICFs and SIPs provided we get credible costand performance data.
Replied By: Therese Stovall from Oak Ridge National Lab
01 - Nov - 2006 3:34 PM
Response to Werner...
Please see page 3 of the supporting doucmentation for the equations used to evaluate masonry walls. You can find the supporting documentation at http://www.ornl.gov/sci/roofs+walls/insulation/supdocal.pdf. Also see page 4 and Appendix B for basement wall calculations.
Replied By: Martha VanGeem from CTLGroup
28 - Nov - 2006 4:09 PM
Ducts, regression equations, and basement insulati...
Response to ORNL request for comments on Insulation Fact Sheet
My response is based on the supporting document at http://www.ornl.gov/sci/roofs+walls/insulation/supdocal.pdf, as referenced by Therese Stovall in a posting dated November 1, 2006.
I have the following comments:
1.) On page 2, the document states, Ducts were assumed to be located in unconditioned spaces. This assumption is too conservative for northern climates (ORNL Climate Zones 5 through 8 including Missouri and Tennessee) because in most houses in northern climates, ducts are located within the conditioned space. The effects of this are also discussed on page 35 of the supporting report. I recommend that ducts be assumed to be located within conditioned space in colder climates (ORNL Climate Zones 5 through 8).
2.) On page 3, reference is made to regression coefficients for masonry walls from the PEAR program. Updated regression coefficients or modeling using EnergyPlus should be used for masonry (mass) walls for the following reasons:
a.) The coefficients are not accurate and do not make sense. Mass walls save energy during heating as well as during cooling. The Portland Cement Association has a report ( Thermal Mass Comparison of Wall Systems, PCA CD026, http://www.cement.org/bookstore/profile.asp?store=&pagenum=1&pos=0&catID=&id=2165) that shows energy savings for mass walls in cold climates as well as warm climates. If ORNL would like a free copy of this report, I would be glad to provide it.
b.) The coefficients were most likely developed in the mid-1980s because the report references 90.2P. Modeling has become easier since then.
c.) The regression equations do not take into account that mass effects vary with climate.
d.) The regression equations do not take into account whether insulation is located on the inside, outside, or integral to the wall. I recommend considering two cases and changing the name from masonry to concrete and masonry or mass. The two cases would be mass walls with interior or integral insulation and mass walls with exterior insulation. The reason for the distinction is that walls with mass exposed to the interior ( exterior insulation ) save the most energy. Making the distinction will help educate the public that this is a desirable way to save energy.
e.) In my opinion, there is probably not a need to have a separate category for ICFs. They will fall into the category of mass walls with interior or integral insulation and will most likely exceed recommendations that are developed for standard concrete and masonry walls.
3.) Results from DOE-2 computer simulations performed at CTLGroup show that it is not cost effective to have basement insulation in IECC Climate Zones 1, 2, and 3 (ORNL Climate Zones 1 through 4). While a small amount of energy is saved in the winter in these zones by using basement insulation, there is a summer penalty for insulating basements. More energy is used in the summer due to the basement walls being insulated and decoupled from the cooling effect of the earth. The overall result is an increase in energy cost due to basement insulation in IECC Climate Zones 1 and 2 and an insignificantly small total energy savings in IECC Climate Zone 3 that does not justify the cost of insulating. This is also consistent with the 2006 IECC that does not require insulation in basements in IECC Climate Zones 1 through 3. I suggest the modeling for basement insulation be updated to be more accurate and that no basement insulation be required in ORNL Climate Zones 1 through 4.
Martha G. VanGeem, PE (Illinois)
Replied By: John Loyer from Icynene Corp
28 - Nov - 2006 4:24 PM
Mgr., Codes and Regulatory Affairs...
What follows is a summary of specific comments submitted to DOE. We have made our comments in MS Word for ease of inclusion and reserve the right to submit additional comments as needed.
Please notify us if/when new comments will be received before the final recommendation is published.
As an overall comment, the recommendations listed herein rely to heavily on opinion without any justification. These recommendations seem to be made with no data to back up the practices. Is this fact sheet used to sell certain types of insulation or improve the overall energy efficiency of the thermal envelope? What is the intent? Not enough attention is paid to air sealing with insulation. Moreover air sealing is much more cost effective and somehow that is lost in translation. This somehow needs to be rectified with current code practice and economic justification, as well as best practice. Opinion should NEVER enter into this document. We would also request that comment be taken on the proposed changes to the new version. Any recommendation of proprietary types of insulation (eg: R-15 high density batts) should be avoided. There is also not enough attention paid to lessons learned from the DOE Weatherization Program which showed us that air sealing was easier and much more economical than adding insulation. Further, the Building America Program s research will bear this out as well and should be included throughout. Updated references to current codes and standards are very much need as well.
If pictures of insulation are used anywhere in this document they must show an application for all major types...cellulose, foam, and fiberglass. Giving preference of one type of insulation over another should be avoided.
We have submitted specific comments on the old fact sheet to DOE and would expect the open and closed cell foam will receive more fair treatment this time around. Moreover the three step process to determine what insualtion is correct is counterintuitive and cumbersome. Why not reproduce the r-value tables in the 2006 IRC and IECC as reference and say these are recommended by consensus of code officials and experts nationwide? Homeowners will be discouraged from participating. The new version needs economic justification. It also COMPLETELY ignores performance based compliance to construction.
Additionally, a caution should be inot the new version to the homeowner on quality installation. Please refer to the NAHB Research Center Certified Insulation Installer Program and RESNET recommendations. These programs were created because of the problems inherent in do-it yourself or improper professional installations. We all know what results in improper installation (eg: mold, moisture problems, and poor performance).
Replied By: from
30 - Nov - 2006 3:20 PM
NIAMA, PIMA and XPSA Comments...
The main comments for the ORNL analysis methodology are shown below for the categories that ORNL has requested comments. For a full set of comments, refer directly to chapters 3, 4 and 5 in this document.
Cost Data, Life Cycle and Calculation Methodology:
The energy cost data does not include taxes, customer charges and demand charges, which does not present a fair evaluation of the actual cost of energy (comment 3.1.3). The fuel price escalation factors used in the previous ORNL analysis were not for the complete life span of the insulation. A recommendation is made to use the fuel cost over the life of the insulation (comment 3.1.1). The life span for insulation used in previous analysis was a period of 30 years for new homes, but in reality the insulation life span is the same as the house and should be considered to be over 50 years (comment 3.1.2).
The prices for insulation appear to be based on a very minimal set of data. The Department of Energy should consider helping to increase the acceptability of the insulation cost data (comment 3.2.1). In addition, the lifecycle analysis should account for future avoided upgrade costs (comment 3.2.4) and the value of future green house gas emissions (comment 3.2.5). Additionally, a fairly simple addition would be to include the cost reduction associated with decreasing the HVAC s rated capacity and duct system size due to increased insulation
(comment 4.2.1). The simplified heat transfer calculation procedures proposed by ORNL present similar trends to hourly building energy simulations and are an appropriate approach to reducing computing time while maintaining a level of accuracy (comment 4.1.2).
We would also emphasize that not all benefits derived from higher insulation R-values are easily quantified in economic terms. Some of these include health benefits due to reduced pollution as a result of using less fossil fuel and reduced stress resulting from quieter homes with higher levels of insulation. When making R-value recommendations, it is important to consider benefits like these, even if they cannot be easily assigned a dollar value.
Recommended R-Values and Presentation of Recommendations:
Overall, it is recommended that ORNL present recommended insulation values that are representative of the local region (comment 4.1.3) and that are fuel neutral with weighted results based on regional housing characteristics (comment 5.2.3). In addition, it is best to align the recommendations with new industry standards such as the climate zones in the IECC and IRC (comment 5.2.1).
The recommended results should be simplified further to decrease confusion and make them easy to use (comment 5.2.2), which could be accomplished through a reduction of the number of recommendations or the addition of a simple and interactive dynamic map (5.1.1). Additional information about the long-term benefits of insulation (comment 5.2.4) and about the environmental benefits of insulation (comment 5.2.5) should be included in any presentation format.
This is the Executive Summary of more extensive comments submitted directly to ORNL.
NAIMA, PIMA and XPSA Comments on the DOE National Recommendations for Residential Insulation Levels
Replied By: Ken Bettger from Ken Bettger, Consultant
01 - Dec - 2006 9:01 AM
Thanks for the invitation to provide input on development of improved national building insulation guidelines. Achieving greater efficiencies in building energy consumption clearly represents a significant opportunity for all stakeholders, from consumers cost of ownership, all the way to U.S. dependence on foreign energy sources.
Comments are listed by topic below:
There exists a significant statistical risk that world-wide reserves of both oil and natural gas are overstated. This includes estimated undiscovered oil and gas, communicated reserves and communicated proven reserves. Likewise it is also possible that the reserves are understated, however it is probably safe to say that there is an increasing level of awareness that the former is the more likely case. Therefore it seems that the Department of Energy should take a measured approach in defining fuel and energy prices for use in the analysis factoring into the pricing predictions, the statistical risk that world-wide demands will exceed supplies or that foreign political issues will create disruptions.
It might be a good idea to explore the issue of future energy prices with Robert Hirsch, PhD (Science Applications International Corporation), author of The Hirsch Report, prepared for the Department of Energy in early 2005. Another good source for information would be Roger Bezdek, PhD (Pres, Management Information Services, Inc.) a co-author with Robert Hirsch on several related reports.
Building Energy Consumption Models:
There is almost universal agreement that conserving energy in buildings is one of the highest priorities for the U.S. Since insulation is one of the key elements in conserving energy and the insulation guidelines are intended to have a very highly leveraged effect on building construction and refurbishment, it seems that the mandate for accuracy is high, wherever it can be achieved. Therefore it follows that the best modeling tools should be used to produce the most accurate characterization of the energy efficiency performance for new and existing buildings. It seems that building-to-building variation should be addressed through statistical methods that are applied to the most accurate energy use data for the representative sample buildings. If the models used to generate representative sample building energy usages produce inaccurate data to begin with, the resulting outputs, conclusions and recommendations would certainly be subject to serious question. In summary, use the best energy modeling tools and the best statistical analysis tools. This stakes are too high not to.
The Fact Sheet format should be refreshed. At the end of the day, if valuable time and energy are invested to produce high quality analysis and recommendations, then the message should be communicated in a fashion that will be convincing to the millions of people that would derive benefit from that message. Again, the best result probably will come through the involvement of a communication / messaging expert. No names come to mind at this moment, but if the team wishes to pursue this and needs references of proven experts, please contact me.
Replied By: from
04 - Dec - 2006 1:14 PM
George A Chrenka...
NU-WOOL Company is a cellulose insulation manufacturer and welcomes the opportunity to comment on the proposed changes to the DOE Fact Sheet and changes to minimum R-values.
In the past two years there has been an effort on the part of some individuals, through the ICC code process, to raise minimum R-values that would undoubtedly favor some insulation types. These efforts have fortunately met resistance by the voting members of ICC. Had these proposals passed, cellulose and light density foams would have been essentially eliminated from the mainstream building process. While it could be argued and was by those proposing these restrictive changes that cellulose and foam could use insulative sheathing to compensate for the slight change in minimum R-values, the reality is that builders are, understandably, driven by costs, a change in sheathing affects costs in materials and labor. This change would have added cost to the builder and would have curtailed the use of cellulose and foams from most builders.
All manufacturers of insulation materials encourage and support the conservation of resources through energy efficient design. But this change must be weighed against the reality of product performance. The recent code actions would have set the minimum R-value for common 2x4 construction to R-15. Cellulose and light density foam can only achieve R-13. As was argued at the code actions, if the minimums are changed they should be a multiple that all insulation products can meet. While I am not an expert on the manufacture of foam products, cellulose requires many times less embodied energy to produce than glass insulation and is certainly a Green product: This is a product we do not want to lessen in the marketplace.
Economic decisions on increased R-values should be based on reasonable payback formulas. I believe that in the past DOE has based their economic analysis of increased R-values on reasonable returns of 7 years. Raising minimums two-points, i.e., R-13 to R-15, as was proposed, requires decades to recover based on independent modeling. The proposed Fact Sheet from DOE mentions many times the importance of controlling air infiltration; cellulose and foams are very effective for controlling air movement. These are products that should remain a viable choice for the consumer.
Replied By: from
05 - Dec - 2006 2:19 PM
Dow Comments on DOE - ORNL Optimal Insulation R-Va...
Ms. Stovall, Mr. Desjarlais and Mr. LaFrance,
Thank you for the opportunity to comment on DOE ORNL methodology for determining optimal Insulation R-Value and specifically the ZIPCODE program. We offer the following comments and suggestions:
To assist in consumer education, in the user in-put section, do not display insulation choices that are below the code required minimum R-Values per zip code. Insulation choices currently shown under the cost button should not allowed the selection of insulation level below code requirements. Adjust the table of inputs so that the lowest displayed R-Value choice is the minimum code requirement and labeled as such. The other R-Value selections available would be the enhanced insulation levels as is currently done.
Include a calculation of total CO2 emissions per selected level of insulation vs. the emissions generated at the code required minimum insulation level for the specific zip code. Education of homeowners as to how much energy is saved through increased insulation levels that result in reduction in total emissions over time vs. a base case will promote energy savings on a broader scale. Consumers should be made aware of the effects of investing their money vs. energy reduction and how that can influence their environment over time.
Incorporation of the impact of windows (glazing):
It does not appear that the program considers variable glazing percentages. Since variations to glazing percentages can greatly influence envelope performance we would suggest a simple user feature that allows two choices 1) home with a large number of windows (i.e. maximum code allowed) and 2) home with a small number of windows. This user choice would then be tied into the program to reflect the effect on envelope performance. At a minimum, if no programming changes are made, add a section the the Insulation Fact Sheet on window (glazing) percentages and their impact on overall home insulation.
The Computer Program:
Put in a button on the output screen so you can go back to the inputs page. Currently you are bounced back to the zip code input page.
Explain on the input and output screens what the discount rate is (i.e. if you invested money in a different way, the discount rate is the assume rate of return you would have expected to get.). This is unclear and should be better defined via a help type dropdown or clearer language.
Include the option to see all the assumptions used and output calculations totals. Right now all the user can see is cost of the insulation. Emphasize, how much total money the consumer saved with their insulation investment vs. what they spent on insulation. Also include how much they reduced their monthly energy usage ($) total. One way to do this is to add an second column to the Insulation Cost Table (on the output page) which would show the total savings each option will bring.
We believe some of the value of the insulation is not currently captured in the program. Assuming a homeowner chooses to spend his money in added insulation and thus reduces his monthly energy usage, it should be assumed, in this model, that the monthly dollar savings realized is invested with the same return (discount rate) as the original investment alternative calculation. The algorithm should include the present value calculation over the lifetime of the invested monthly energy saving dollars (20 or 30 years).
We concur with the responses from NAIMA, XPSA and PIMA.
Up-date to the Insulation Fact Sheet:
We are assuming ORNL will update the actual R-Value for each type of insulation. The current Insulation Fact Sheet does not reflect the change in R-Value for multiple types of foam plastic insulation that have gone through blowing agent changes
We d be happy to discuss this with you or others, please feel free to us a call.
Greg Bergtold (989) 636-6371
Mike Mazor (989) 636-6853
Joann Surma (989) 636-8655
The Dow Chemical Company
Dow Building Solutions
200 Larkin Center
Midland, MI 48674
Replied By: Craig Conner from Building Quality
06 - Dec - 2006 3:02 PM
Insul Fact Sheet comments...
Thank you for taking comments on the update to the Insulation Fact Sheet published by the Department of Energy and produced by Oak Ridge National Laboratory. I hope you also allow comment on drafts, prior to finalizing the new version.
Overall the Insulation Fact Sheet (IFS) shows its age. The IFS is significantly out of date and needs to be completely rewritten. Presuming that the document will be largely rewritten, these comments will focus on the replacement document. I will cite only a few statements from the IFS. For purposes of these comments, I ll call the rewritten document the New Insulation Fact Sheet (NIFS).
The mix of insulation materials used in the market has changed markedly since the IFS was written. The use of blown cellulose insulation has expanded significantly, which should be reflected in the NIFS by treating blown cellulose as a mainline product. Spray-applied open-cell foam is a fast growing section of the residential insulation market, as well. Sprayed foam has become very common in some regions and applications, (e.g.: sprayed foam use in unvented attics is common in some southern regions. Sprayed polyicynene insulation, the foam mentioned above, is growing rapidly in the residential market, but is not even mentioned in the IFS. (Spray high-density foams, or polyurethane foams, are much less common in residences.) The use of ICFs (insulated concrete forms) has expanded a great deal.
Overall the IFS is too focused on fiberglass and its derivative products. The NIFS should be broadened to better cover the other mainline insulation products. Because these other products have differing characteristics, applications, and practical considerations, it may make sense to have a short individual section on fiberglass batts, blown cellulose, open-cell sprayed foams, insulated sheathing, SIPs (structural insulated panels) and ICFs. The need for more attention to characteristics of non-fiberglass products is sometimes obvious. For example, the IFS s implication that blown cellulose and spay foam are fire risks is unacceptable ( Do not insulate bare, hot flue pipes. DO NOT USE ANY COMBUSTIBLE PRODUCTS, SUCH AS CELLULOSE INSULATION OR PLASTIC FOAMS, HERE. , capitals in the original, page 8 of IFS), given that other common construction products, such as wood, are much more combustible. NIFS should reflect the diversity of the insulation market.
The NIFS should be better targeted to the actual audience. The audience is not DOE, DOE lab staff, engineers or various product manufacturers. The audience is consumers. As written, the IFS does a poor job of targeting consumers. Consider splitting the NIFS into two brochures, one for new homes and one for existing homes. Consumers typically divide into those who are interested in new homes and those who are interested in existing homes. The options for new and existing homes differ significantly. Consider making the individual topics within the NIFS standalone, an approach that would work well if the NIFS gets reformatted into web pages. Some thought should be given to how additions and renovations are split between the two brochures.
The presentation of the suggested R-values, a key point for the existing IFS, is particularly poor. A three-step approach that starts with zip codes or a map and moves through two additional tables, all on separate pages, is confusing and unnecessary. The answer is not complex, the presentation should not be complex.
Revise or eliminate the references. Don t refer the reader to technical documents that are likely over the reader s head (Builders Foundation Handbook or Moisture Control Handbook). Don t recommend the reader reference the codes. Simply reproduce or summarize the relevant information, for example the insulation tables from the International Residential Code (IRC) and the International Energy Conservation Code (IECC). Additionally, some web resource recommendations may be appropriate.
Consider changing who designs the way information is presented in the NIFS. The IFS s poor targeting of its audience suggests that staff who produce refereed journal articles may be the wrong staff to write this document. In addition, get comments from a few reviewers who lack a background in buildings, lack relevant college degrees, and are non-technical; all people who better represent the audience than the experts. Let the lay reviewers explain to the experts what was not clear.
The NIFS for new homes should have as one of its main focuses the strategies for high efficiency new homes. NIFS readers are almost certainly interested in energy efficiency. DOE wants to promote energy efficiency. Some level of minimum efficiency is often provided by code. Provide the reader with something more interesting. I suggest half of NIFS be devoted to the high efficiency homes, homes that often significantly exceed code. The basis for the high efficiency homes should not be an arbitrarily picking fixed percentage (20%, 30%, 40%) above code. The Building America Program, and even lessons learned from the Weatherization Program would provide some basis for a high efficiency home. Zero-energy home are beyond the practical price range of most consumers, therefore don t belong in NIFS as any more than a reference.
High efficiency homes need to be characterized by more than R-value. Some high efficiency homes have only moderately higher R-values, but perform well due to other technologies and techniques like air sealing. Some high efficiency homes may have slightly lower R-values; for example, sprayed foam applied at a lower R-value to the ceiling of an unvented attic brings ducts inside and lowers the overall energy use.
Looking at existing high efficiency homes, it is clear that high efficiency homes are much more likely to use blown cellulose, sprayed foam, SIPs and ICFs than most homes. Fiberglass batts probably comprise over 2/3 of the existing residential insulation market; however, in the high efficiency home market DOE wants to encourage, fiberglass batts represent significantly less than half the high-efficiency residential market. Consumers who want to build high efficiency homes need to understand the strategies that are working for high efficiency homes. The DOE lab staff that work on these documents should describe what is working in real buildings, not just reproduce the assumptions that went into their software. Interactions with mainline, profit-making builders who build energy efficient homes would be beneficial.
Although perhaps not the NIFS focus, the document(s) should mention a short list of additional non-insulation practices that go well with a well-insulated home; items like proper HVAC sizing, high efficiency heating systems, moving ducts indoors, high efficiency windows, etc. Moreover, indoor air quality considerations like separation of the garage from the living space, sealed combustion appliances, eliminating unvented heaters, radon control, and moisture control should also be considered. These topics obviously get more emphasis with the high efficiency home.
The IFS focuses too much on R-value. The IFS statements additional insulation would be a good investment for the buyer , The higher the R-value, the greater the insulating effectiveness. , It is possible to add insulation to almost any house. & the initial investment will pay for itself in reduced energy consumption (all quotes from the IFS) can be true or false and are misleading. Higher R-value is not necessarily economic. Energy savings, not higher R-values are the goal. Variations in air sealing and installation quality are often more important than variations in R-value. Installation quality is hardly dealt with by the IFS. Controlling infiltration and air sealing techniques need more attention.
As a practical matter, the NIFS should assume insulation levels in the 2006 IRC / IECC as minimum levels. (If ORNL concludes some part of the 2006 codes are very uneconomic, either too high or low, then that conclusion needs to be vetted.) ORNL may decide levels somewhat above code are economic for specific situations, but often this is not the case. Situations that might justify much higher R-values are usually to be advised against; for example, homes with electric furnaces in Minnesota. Least cost curves are flat near the optimum. NIFS should hesitate to go below code or to make minor distinctions between situations.
Goals other than energy-efficiency can produce R-values above (or below) code. Those limited cases should be detailed separately. A very energy-efficient home might choose higher R-values for non-economic reasons, perhaps just because they want a low-energy home. A high efficiency home might tradeoff first costs by raising the R-value enough to lower the overall load to eliminate a portion of the HVAC system. Some products may be more efficient even at below code R-values, if they provide a good air barrier. In areas with termites, any insulation that gives termites a place to hide may be a bad idea. ICFs can have R-values above code, simply because the insulation that makes the forms needs to be thicker.
Note what the market says about products and consider eliminating some products from the recommendation list. For example, R15 batts are uncommon. Presume the market has a reason (in this case R15 batts are significantly more expensive than the common R13 batts). As another example, R11 insulation has disappeared from the IRC / IECC. The market is in the process of eliminating R11 batts, in favor of R13 batts. The IFS frequently names R11. The NIFS should probably eliminate recommendations for R11 batts.
Since the IFS was written, a new set of climate zones was developed by DOE and has been widely adopted. The climate zones defined by the 2006 IRC / IECC should be used to define the requirements for the NIFS. These climate zones have the advantage of being used already in the codes and other areas (ASHRAE, EPA, Building America, etc.).
At code minimum R-values installation quality, and control of infiltration can be significantly more important than increased R-value. For example, a poorly installed R21 wall with air leakage through the insulation is worse than a well-installed R13 wall with insulation that fills the cavity and is air sealed. High efficiency homes usually emphasize quality installation, airtight construction, air quality, and the design of the house as a system. Although the consumer looking for a high efficiency home is interested in cost-effectiveness, it is probably not the primary concern.
A comment on least cost analysis: Often DOE (and other stakeholders) tend to select economic and cost assumptions that yield the results they want. (In previous comment it has been stated, Give me control of the economic assumptions and I can produce any output desired. ) It should be obvious that if economic assumptions produce some kind of minimum which is close to code, then the same assumptions will not similarly produce a highly energy efficient home. DOE will need to select a different method to specify the high efficiency home.
Installation quality is becoming more important. The NIFS should deal directly with installation quality. This includes discussion of voids, insulation compression, and penetrations of the thermal envelope. Items like permanent contact of the insulation in the floor with the subfloor, and permanent contact of insulation with the crawlspace walls have even become code requirements. NIFS should focus more on control of air infiltration. Sealing penetrations is important. Note that infiltration passing though air permeable insulation, like fiberglass batts, can greatly diminish its R-value, etc. Attention should also be paid to details like infiltration at band joists, infiltration though recessed can lights, cold winds through the insulation in floors over unconditioned spaces (like garages), and the common walls on multi unit dwellings. The specific items required to be sealed by code and Energy Star s Thermal Bypass Checklist are two sources of important details defining what installation quality means. A list of key details, or a reference to such a list. is important.
The movement away from R-value towards installation quality, air sealing and air quality issues is best illustrated by the new Energy Star Homes requirements. The new Energy Star sets the existing 2006 IRC insulation requirements as their base . The bang for the buck in efficiency is in quality installation, control of infiltration and systems design.
Comfort is a legitimate issue. NIFS should note that comfort concerns, such as cold spots, are often affected by installation quality and infiltration control.
A number of special situations need to be considered in drafting the NIFS. Situations where increased insulation requires increased framing size will often yield unacceptable paybacks; for example, high levels of insulation in cathedralized ceilings. In some climates and house designs with spray foam insulation saves energy by bringing the ducts inside the conditioned envelope, even with a lower insulation R-value. Sealing the band joist area against air leakage is more important than high R-value, so a moderate R-value that air seals can be a big advantage. Basement insulation recommendations may have as much to do with moisture management as energy efficiency. Don t forget to put insulation in the context of the house itself. Insulation is not a separate entity but merely one way to make a house more energy efficient
In addition to being difficult to use, the IFS method for defining the insulation needed for existing homes can produce incorrect results (IFS page 6). In particular, the NIFS should highlight situations where it is easy to add insulation and situations where it is hard (or read cheap or expensive ). An example of easy-- when a remodeling job opens up a cavity on the exterior envelope, it makes sense to fill the cavity with insulation. On the other side, if a wall was R1 or R2 short of the recommendation, it would seldom make sense to cut into the wall or apply new siding just to add R1 or R2. The NIFS recommendations for additional insulation in existing homes should be much more practical.
Give the consumer more practical ways to identify problem areas in existing homes. It can be as simple as Feel for cold spots on cold days or where to buy smoke sticks . The IFS suggestion about engaging a home inspector, utility program or energy auditor is good advice. The NIFS might add more advice on where to find them.
Include a short section on green products in the NIFS, as a growing number of consumers are interested. A number of insulation products carry recycled content. Blown cellulose insulation should be a featured success story, as it is an example of making a useful, economical, and competitive product based primarily on recycled materials.
An unvented attic is often a good design. However, the IFS says A well-insulated attic should be adequately ventilated to prevent moisture accumulation. , Twice as much ventilation is recommended if there is no vapor retarder. These quotes from the IFS represent bad building science. Unvented attics are allowed by code now. Likewise, the code options for unvented crawl spaces have increased.
Perspectives on vapor retarders have changed markedly since the IFS was written. Code requirements are relaxed in the 2006 codes and further relaxation is being proposed in new codes. The perspective has shifted from block moisture to keep water out, moderate vapor diffusion, and allow materials that get wet to dry . As homes become tighter, moisture related becomes more important. The new moisture mantra is Materials get wet, keep out the bulk of the moisture, and let them dry .
The moisture addendum to the IFS needs more actionable items. The NIFS version should be shorter with a more practical focus.
The IFS is too long. I believe the NIFS the can be shorter, even if it covers all the topics above. Focus on simple, practical and clear advice to consumers.
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