Brennan Less replied to Blake Reid's discussion Hot Tubs
"I agree with Sean on this. Newer units should have an Energy Guide Label (see template here https://www.apsp.org/hot-tubs-ihta/resources/portable-electric-spa-...), which will estimate the annual usage in standby mode (i.e., temp set, lid closed, no…"
Sep 24
Brennan Less replied to Brennan Less's discussion Get paid to help break down the costs of Deep Energy Retrofits in homes!
"Thanks to those who have already contributed! To clarify, we need project data submissions that have cost resolution at the measure/task level. For example, a line-item $ cost to insulate the attic to R-60, and another line item $ cost to seal and…"
May 18
Brennan Less posted a discussion
Berkeley Lab is gathering information from the industry to better understand the costs and challenges of deep energy retrofit (DER) projects in homes. We are interested in DER projects that use a comprehensive, whole-home approach to drastically…
May 14
Brennan Less replied to Greg O'Beirne's discussion building envelope air tightness studies
"My research team at LBNL has assembled a large database of envelope leakage measurements from homes across the US (>150,000 homes). The project website is under maintenance right now, but should be back up soon for interactive plotting. A number of…"
May 14
Brennan Less replied to Brennan Less's discussion Summer mid-day Condensation in newly insulated unvented, cathedral ceiling using foil-faced polyiso
"So, here's my thinking on furring down the ridge and insulating a bit from underneath. First, it might keep the ridge above the dew point, but it could very well remain in mold growth territory above 80% RH. Second, even if the ridge was protected,…"
Aug 11, 2019
Brennan Less replied to Brennan Less's discussion Summer mid-day Condensation in newly insulated unvented, cathedral ceiling using foil-faced polyiso
"Thanks Paul, do wish I had read that article earlier this year. It's frustrating that this assembly meets the letter of the model building codes, but then there's this apparent consensus that this is a sketchy or DIY practice? My insulation sub and…"
Jul 25, 2019
Brennan Less replied to Brennan Less's discussion Summer mid-day Condensation in newly insulated unvented, cathedral ceiling using foil-faced polyiso
"The "blocking" is more like an undersized ridge beam running the length of the room. I'm sure it's thermally bridging and represents a hot surface, but cool enough to support condensation at likely very high vapor pressure. I think the air up there…"
Jul 25, 2019
Brennan Less posted a discussion
Greetings, We recently placed 3.5" of RMax foil-faced polyiso foam board (air and vapor impermeable) neatly cut and placed between the rafters of our cathedralized ceiling home in the Santa Cruz Mountains of California (hot dry summer, very wet and…
Jul 25, 2019
Brennan Less replied to Don Fugler's discussion Depressurization/make-up air issues in Kitchen Ventilation
"This is a great sub-thread, thanks you two! I'll be looking into some of the projects/studies you've referenced. "
Mar 26, 2019
Brennan Less replied to Don Fugler's discussion Depressurization/make-up air issues in Kitchen Ventilation
"Thanks again for the thoughtful perspectives, David. I've never heard the thermal lag justification for use of 99% design conditions. Is that written in Manual J or elsewhere? Very interesting stuff, especially the linkage between using different…"
Mar 26, 2019
Brennan Less replied to Don Fugler's discussion Depressurization/make-up air issues in Kitchen Ventilation
"Dara, I've not heard of this issue before, and it's very interesting, indeed. But it sure seems like this could happen due to any number of issues, such as the operation of other exhaust devices, continuous exhaust fan, or even just any long time…"
Mar 26, 2019
Brennan Less replied to Don Fugler's discussion Depressurization/make-up air issues in Kitchen Ventilation
"David, I know the pressure reaches static levels quickly. I meant, how quickly then does radon begin to emit or be drawn into the space at a higher rate. For example, initially drawn by depressurization into a basement and then rising up into the…"
Mar 25, 2019
Brennan Less replied to Don Fugler's discussion Depressurization/make-up air issues in Kitchen Ventilation
"Hi Don, great sequence of questions, and a couple of thoughts.
Overall, I just don't see depressurization, especially short-term and infrequent (as caused by cooking appliances), as being a major risk to health or building durability. Running a…"
Mar 25, 2019
Brennan Less replied to Rob Madden's discussion Determining Duct Leakage based solely on blower door and pressure pan testing
"The DeltaQ duct leakage test uses only a blower door fan to measure duct leakage to outside at actual HVAC system pressures, as they exist/occur during system operation. So, for example, a leak at the return plenum is not treated the same as a leak…"
Mar 14, 2019
Brennan Less commented on Jim Gunshinan's blog post Our First Year with Solar Panels, by Chris Stratton
"Hey Chris, y'all are kicking butt!! I'm sure your new HVAC won't use any energy, because you won't turn it on, right? ;) What a cool, cool project. 
On a related note, our whole region just created a community power agency (Monterey Bay Community…"
Jul 19, 2018
Brennan Less replied to Linda Wigington's discussion Good Eating with Reduced Cooking Emissions in Kitchen Ventilation
"Cook outside, as much as you can, and close your doors/windows while you do it ;) "
May 24, 2018
More…