The Latest from the Energy Vanguard Blog

This fan should not be your first choice for keeping cool.  See point 4 below for the reason.
Posted by Allison Bailes on July 11, 2018
Here we are in the middle of air conditioning season.  So why don't we chop down some myths and misconceptions about ceiling fans.  What got me on to this topic was a video of a fan with blades that hide on top of the fan when the fan is turned off.  Sounds clever, but it's a ridiculous idea....
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Dew point isn't just for understanding condensation
Posted by Allison Bailes on July 9, 2018
I've been on a bit of a mission for the past several years.  My goal is to get more people thinking about humidity in terms of dew point rather than relative humidity.  Why?  Because relative humidity is misleading.  That whole "relative" thing is a bit slippery, you know. For example, I've had a...
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What exactly is a low-load home?  (Architect Richard Levine stands in front of the low-load, solar home he designed and built in the 1970s. Photo by Energy Vanguard)
Posted by Allison Bailes on July 6, 2018
I found out last month that the Air Conditioning Contractors of America (ACCA) is working on a new design manual.  You probably know of some of their other manuals:  Manual J, Manual S, Manual D...maybe even Manual T.  They have quite a few others as well (P, H, Zr...) but now they're working on...
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Good HVAC design is 99% invisible.  (Photo of living room by Ceylon Tea Trails from flickr.com, used under a Creative Commons license.)
Posted by Allison Bailes on July 3, 2018
Sometimes people are bothered by how things look.  They don't want a return grille showing in that location or they'd rather have the supply registers low on the wall or they just can't stomach the thought of a wall-mounted ductless mini-split anywhere.  We all have our preferences about how things...
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ASHRAE 62.2 standard for residential ventilation
Posted by Allison Bailes on June 29, 2018
It's been a while since I've written about what I had been calling "The Great Ventilation Debate" back when Joe Lstiburek was battling the ASHRAE 62.2 residential ventilation committee.  The 62.2 committee meets in person twice a year at the two ASHRAE conferences and they just met last Friday and...
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Ventilation grille bringing in straight outdoor air at the ASHRAE conference hotel in Houston, Texas  (photo by Nikki Krueger of Therma-Stor, used with permission)
Posted by Allison Bailes on June 24, 2018
I've been going to the meetings of the ASHRAE residential ventilation committee (SSPC 62.2, to be specific) for the past few years.  As a matter of fact, I'm writing this article from my room in Houston, the site of the summer meeting.  It's always interesting to go to these things because the...
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Staying cool with air conditioning
Posted by Allison Bailes on June 11, 2018
It's getting hot out there. Here in the Southeast, we love our air conditioning.  In fact, without air conditioning, far fewer people would live in places like Houston, Hattiesburg, and Sopchoppy.  And that's true for the hot, dry places, too, like Phoenix, El Paso, and Boron. So if we're going to...
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Sample Manual J heating and cooling load calculation report
Posted by Allison Bailes on May 23, 2018
When you enter the world of building science — whether through building a house, becoming a home energy rater/building analyst, or just hanging out in cyberplaces like this — everyone talks about the importance of getting actual heating and cooling load calculations based on ACCA Manual J.  A great...
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Oversized air conditioner
Posted by Allison Bailes on May 8, 2018
Many people seem to think HVAC design means you get a load calculation (Manual J in the ACCA protocols) so you know what size system to put in. Hey, that's a great start. It's way better than just using a rule of thumb or Manual E (for eyeball). You don't really want to end up with a ginormous...
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Condensation on stone steps in New Orleans on a February morning
Posted by Allison Bailes on April 18, 2018
If you live anywhere in a warm, humid coastal area, you're no doubt familiar with wet concrete in winter. Some days you walk outside and find the carport slab is soaking wet. How did it happen? Did rain blow into the carport? If it's not rain, is it moisture from the ground that came up through the...
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