Letters: Importance of Principled Design, Feedback, and Insulating that Chicago Bungalow
I am impressed by the Home Energy article about your house (“Design, Construction, and Performance in Ohio,” Jan/Feb ’07, p. 36). Good for you for practicing what you preach, and for being so commonsense about it, instead of jumping on the solar-bamboo fl oorgeothermal bandwagon.
I’d sure like a copy of “A Primer on Estimating Heat Loads and Performance,” and I’d appreciate hearing your logic behind not using an ERV, what with so much ductwork already in the design. I’m also curious how you got your garage to stay over 45ºF all year, as I’ve never seen a garage door that is anywhere near airtight. (I assume your garage has a door.) How did you do that? Also, is it safe to assume that in case of a blackout your house would never go below freezing; therefore you never need to drain your pipes?
New York, New York
Author Allen Zimmerman replies:
I appreciate your feedback. I very much respect and admire your philosophy, expertise, and work. The points you raise are valid and important. Common sense, use of familiar materials and straightforward techniques, and cost-effectiveness are critical to meeting the challenge of greatly increasing the number of energy-effi cient newly constructed and remodeled homes, and the overall level of energy effi ciency in these homes—a challenge that must be met ASAP and industrywide. Where feasible, keeping it simple is an excellent strategy. I warn people who plan to visit my home (so they won’t be disappointed) that it does not have any “exotic” equipment or design features, and that it looks like every other home up and down the street, both inside and outside. I will send you a hard copy of “A Primer on Estimating Heat Loads and Performance.”
Regarding the use of an ERV: Given the various climate, energy source, and design parameters and the additional complexity, space requirements, and expense of ERV, my analysis determined that an ERV system was neither practical nor cost-effective for this house. ERVs are an important component in the mix of materials, methods, equipment, and systems that are available to improve energy effi ciency, and their use should certainly be considered and evaluated on a case-by-case basis.
Concerning the garage: It is constructed similarly to the house in terms of framing, insulation, and air sealing—I used the airtight drywall approach, or ADA—with the exception of the amount of insulation. There are 2 inches of rigid insulation on the exterior of the foundation extending 4 feet inside under the footer/foundation/ fl oor slab; 1 inch of rigid insulation on the exterior walls; and R-30 of cellulose in the ceiling (with R-60 over the studio/laundry room). The overhead door is a high-quality, well-sealed metal unit with a polyurethane foam core (Wayne-Dalton) and is purposely located on the east (lee) side (strong and prevailing winds are from the west). There are no windows; this eliminates another large source of heat loss. There is 1 inch of extruded polystyrene rigid foam installed on the common wall between the garage and the house (there are also fi berglass batts in the wall). The interior walls separating the studio/laundry room from the remainder of the garage are insulated with fi berglass batts. Apparently it is the combination of (1) low heat loss due to convection and air leakage, (2) a small amount of heat gain from the conditioned space, and (3) the ballast effect of the concrete garage fl oor directly on soil that keeps the garage above 45ºF even in very cold weather. In hindsight, it would have been interesting to do a blower door test on the garage.
Regarding a power outage: I suspect that the house would never drop below freezing. The only test case I have to date was once when we were without electricity in the winter for about 24 hours and the outside temperature dropped into the single digits during the night. In this case, the indoor temperature dropped only into the 50s. A longer test period would be needed to determine how the house performs with prolonged cold temperatures without electric power, and the results would be interesting; however, I am not advocating for this to occur! Concerning pipe freezing per se, the fact that I used PEX (which withstands the increased pressure due to freezing better than other materials) provides some additional insurance. Certainly if backup heat was ever needed, in the unlikely event of an extended power interruption during an extended period of extremely cold weather, a small portable propane heater would be adequate for the task.
I have enjoyed our dialogue on the various issues related to energy efficiency.
Principled Design II
I very much enjoyed your article “Design, Construction, and Performance in Ohio” (Jan/Feb ’07, p. 36). As someone who started building superinsulated homes in the early 1980s, I found the article provided all the needed information on performance. Actual monitored energy usage is the only measurement that matters—as I say, the proof is in the results. For a home built slab-ongrade, 1.7 Btu/ft2/HDD is a very good number. A full basement would put that figure somewhere about 1.25 or so.
I agree that the Energy Star system of measurement leaves something to be desired. If only the Energy Star-rated homes were as energy efficient as your home! Energy Star has been around for ten years and is obsolete in light of current energy prices. What has hurt the Energy Star program the most is the lack of a real air infiltration standard. There is no energy efficiency without building airtight, no matter how much insulation is used.
I will attach a copy of my superinsulation case study for five homes I built in Fargo, North Dakota, in the 1980s. I think you will find many similar specifications to your very energy-efficient home. Thanks again for the article.
President, AIRFOIL, Incorporated
Eden Prairie, Minnesota
Allen Zimmerman replies:
I appreciate your kind words and comments about the article and enjoyed reading your case study report. The performance of the homes you built in the 1980s is truly impressive. I too have been an advocate for superinsulated— and, as you indicate, what is just as important—supertight, homes since the late 1970s. In fact, I still have Nisson and Dutt’s Superinsulated Home Book (New York: John Wiley and Sons, 1985) and Lencheketal.’s Superinsulated Design and Construction (New York: Van Nostrand Reinhold Company, 1987) in my office reference library.
I looked up, and am impressed by, your company Web site and products (www.airfoilinc.com).
More Praise for Principled Design
Thanks to Allen Zimmerman for sharing his project with Home Energy readers (“Design, Construction, and Performance in Ohio,” Jan/Feb’07, p. 36). Just as homeowners often fail to consider payback potential when evaluating energy-efficient products and upgrades, many in our profession blindly recommend efficient products and methods without regard to life cycle cost. It’s refreshing to see someone take a more pragmatic approach, even if it means using an inefficient product. In this case, Mr. Zimmerman made a rational decision to use electric baseboard heat in his very efficient home in north central Ohio. And unlike the authors of many case studies on efficient design, he held back until he was able to present consumption data that validated his decision.
As we make our building envelopes tighter and more efficient, each subsequent efficiency measure becomes increasingly harder to justify. We need to demand better life cycle analysis tools (and use them), and not rely on marketing hype that invariably compares the product to unrealistically high baselines.
Project Manager, HVAC Services
Environmental Building Solutions
Matthews, North Carolina
Allen Zimmerman replies:
I appreciate your feedback regarding my article. I very much respect, admire, and have learned from what you and other home performance professionals have been able to accomplish in the difficult real-world housing market and environment. The scope of your company’s work, and its Web site (www.environmentalbuilding.net), are truly impressive.
Importance of Feedback
I read Daisy Allen’s article “Feedback on Feedback” in a recent issue of Home Energy (Jan/Feb ’07, p. 13) and have the following comments:
First, congratulations to Home Energy for publishing the article! Articles focusing on the social and behavioral issues affecting energy use are few, and I encourage this magazine to continue publishing these kinds of articles.
Second, congratulations to Ms. Allen for conducting this type of study! As she correctly pointed out, there have been only a handful of studies examining continuous energy use feedback in a residential setting. We need more of these studies. And since this appears to be a college-based study, I am sure the support for this type of study was bare-bones. I am glad to see a new generation of analysts addressing this important topic. And I hope more social/behavioral studies continue—with the participation of students and with more financial support in order to get larger samples.
Third, I see that the company that manufactures the Energy Detective has released a new version of its product, the Energy Detective 5000. I hope the company, Energy, Incorporated, also can financially support similar studies to see how effective their new technology is in saving energy.
Fourth, the findings show that this type of technology by itself is not sufficient for reducing residential energy use. I think the negative findings (for example, “the majority of sample households did not use the monitor as frequently or as intensely as they could have done and/or had planned to”) reflected one of the key limitations of this study: “Homeowners were given no specific advice on using the monitors to save energy. They were simply told to use the monitors as they liked.” There definitely needs to be more interaction between the experimenters and the homeowners. Providing more information is not sufficient. Better displays (such as historical data in a graphic format) might help. But they will not be as valuable as someone discussing the information with the homeowners. This will obviously take more time and money, but the resulting effects will be much more positive. This represents a
lost opportunity that needs to be addressed if we really want our society to be more energy efficient.
Lawrence Berkeley National
Insulating That Chicago Bungalow
I have some concerns about insulation procedures. We have a typical bungalow in Chicago. The house was built in approximately 1919, along with the majority of bungalows on our block. The house has an unfinished, drafty basement, and ditto for the attic and porch. The pantry is too narrow for the refrigerator; thus it has to be on the porch. Due to financial reasons we haven’t been able to have the porch insulated, but that’s about to change soon.
In the summer the refrigerator operates well enough, but at certain temperatures it runs slightly warmer than it should. And it’s pretty much the same during certain winter temperatures. The ice only freezes slightly, and sometimes food thaws and has to be tossed. By the way, the refrigerator is only two years old.
Would it be overkill to have the porch insulated and heated, or would a thorough insulation-only job be sufficient? It would be nice to get a snack from the refrigerator knowing the porch is toasty warm on a wintry night!
Any suggestions that you can provide with regard to my questions are greatly appreciated.
Ice-Cold Chicago, Illinois
Home Energy author and architect Paul Knight, principal of Domus PLUS, in Oak Park, Illinois, replies:
It’s my understanding that refrigerators are designed to operate within certain temperature ranges. For example, refrigerator manufacturers don’t expect the motors on their refrigerators to “see” very cold temperatures. Likewise, refrigerators have to work harder when it’s very hot, and that can also affect refrigerator performance.
I definitely think the porch should be insulated. If anything, heat (or coolth if you’re air conditioning) will help temper the air in the porch, which should help the refrigerator performance. Intentionally heating the porch would make it very tempting to get that late-night snack.
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