Using Duct Testers
In the July/Aug ’12 Home Energy there is an article on duct blasters (“Testing Duct Testers,” p. 4). There is a sentence in the article that states: “One approach would be to increase the flow and pressure to 50 Pa and divide the result in half for a 25 Pa reading.” This isn’t quite right, because the flow is not linearly proportional to pressure. For duct leaks, the flow is proportional to the pressure to the power of 0.6. So translating from 50 Pa to 25 Pa, you need to divide by about 1.5 (that is, (50/2f5)^0.6).
Lawrence Berkeley National Laboratory
Author Paul Raymer replies:
Thanks for the input. Always welcome. That must have been a misinterpretation of a process I got elsewhere. Luckily the flows I was referring to are pretty small.
Home Energy on Facebook
Just saw a picture of your magazine cover on Facebook (Sept/Oct ’12). A tease on the cover says, “Converting from Steam to Hydronic Heat.” As a heating contractor for the last 32 years, I can assure you that steam is hydronic. Hydronic is the use of water in either the liquid or gaseous (steam) form as a heat transfer medium.
Don’t mean to be a nitpicker but hydronic heat has only a 7% market share nationwide, mostly in the Northeast and we need all the good press we can get!
Robert C. O’Brien
Technical Heating Company
Mt. Sinai, New York
Editors’ note: We shortened the cover line to say “Converting from Steam to Hydronic Heating” because the actual title of the article was a bit too long for the space. The full title of the article is “179 Henry Street—A Case Study in Converting from Two-Pipe Steam to Hydronic Heating” (p. 32).
Author Dan Rieber replies:
What the gentleman says is true. My title assumed of the reader lots of knowledge in the area to understand the difference. Here in New York City, we don’t call steam heat hydronic heating (even though technically speaking it is). We refer to hydronic heating as using circulating hot water to heat a building, as opposed to using steam. It’s all semantics, but I don’t disagree.
I just finished your recent article in Home Energy regarding the California PG&E Energy Upgrade California (EUC) program (“Energy Upgrade California,” Sept/Oct ’12, p. 6). I really enjoyed the article (along with many in past issues); lots of good information, much of it familiar to me working in the New Hampshire Home Performance with Energy Star (HPwES) program. Most of my background is as a building analyst, but I’m finding myself more involved in weatherization program QA/QC.
(1) One thing I don’t understand is, Why do utilities design and brand their own program, when the HPwES program is pretty well defined with good rules laid out for operation and monitoring of the program? I’m figuring it’s more expensive to design and brand a new program like EUC, than to pick up the HPwES template and run with it. Are there objections to the HPwES program that convince utilities to go with their own program instead? Any thoughts?
(2) Also, I work in the QA section of the New Hampshire HPwES program and I’d like to get some advice from more experienced pros like you on how to conduct post-weatherization inspections. Basically our template is to go out to the home after the contractor has left, interview the client, and review and inspect the list of weatherization items the contractor has invoiced the utility for. I’ve felt that this approach is lacking the direct discussion with the contractors when a deficiency or a question comes up regarding the install. Would you say that most of your QA’s are done while the contractor is still on site, finishing up and testing out? I’ve felt this would be a worthwhile change to our procedure and would like your input. The business of weatherization QA/QC is of itself a specialized part of the field, but I have found little specific training or even any weblogs dedicated to it. Do you have any articles coming up or know of any training specific on the business of weatherization QA?
Thanks for any help you can provide. I look forward to your future Home Energy articles.
Horizon Residential Energy Services NH, LLC
Concord, New Hampshire
Author Steve Mann replies:
Regarding your first question, I wasn’t there when PG&E (or the other utilities) designed their programs, so I can’t explain why they seemingly invented everything from scratch. I do know that some of the sampling requirements in PG&E’s program were very similar to Home Performance with Energy Star, so I believe someone in the design process was at least familiar with HPwES. Another factor, which may or may not have come into play in this particular case, is that large organizations generally have a mind of their own, and lots of resources, and feel compelled to do their own thing, regardless of what’s already out there and proven, thinking their program will be absolutely, positively better. I know from first-hand experience that when that happens, they often don’t have any in-house expertise to point them towards some existing excellent resources.
Based on your description of your background, you’re probably much more experienced than I in this type of program. Having said that, here are my observations about the PG&E program relating to your second question.
We started out doing our QA after the fact, with the homeowner, as you describe, then contacting the contractor if there were problems. This created a number of issues:
One more possibly unwelcome intrusion into the household. Some homeowners welcomed the extra eyeballs, some were tired of the whole process and didn’t want to be bothered. The latter cases made it tough for us to make sure we had good QA samples.
The follow-up with the contractor generally didn’t work out that well, especially if the rebate had already been paid. First, there was no financial incentive to the contractor (in fact, there was a financial disincentive). Threatening to remove them from the program might or might not motivate them. Our success with all but a handful of contractors that were doing seriously substandard work was marginal.
Towards the end of my tenure at Build It Green, we came to the realization that doing the final test-out with the contractor, as you also describe, was a better approach. Not only could we identify problems and fix them immediately, we could use it as a mentoring opportunity. Additionally, it had less of an impact on both the contractor and the homeowner. I’m not sure how much of that approach has ultimately been adopted by Build it Green, but the QA team recognized the value of that approach.
In answer to your final question unfortunately, I don’t know of any good training or blogs specifically dedicated to weatherization QA. Perhaps Home Energy’s Training Guide has some pointers, or other Home Energy readers have some suggestions. I would post this question to the Home Energy Pros blog (www.homeenergypros.lbl.gov). You might even be able to start a blog there covering this topic.
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