The Latest from the Energy Vanguard Blog

Plastic pipes usually indicate a high efficiency furnace. But what key piece does this ignore?
Posted by Allison Bailes on April 17, 2017
You can tell how energy efficient a furnace is by its official efficiency rating, the Annual Fuel Utilization Efficiency (AFUE). It's a measure of how much of the heat originally in the fuel that's being burned is available for delivery to the home. The more heat that gets lost up the flue or...
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ventilation energy enthalpy recovery ventilator erv humidity
Posted by Allison Bailes on April 3, 2017
Ventilation is a great thing. Bringing outdoor air into the home and exhausting stale indoor air improves indoor air quality. Well, most of the time anyway. Sometimes the outdoor air quality is worse than indoor air. Sometimes you bring in too much humidity and start growing mold. And sometimes you...
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The RESNET-BPI group on LinkedIn has been in decay, as has the ancient Forum in Rome
Posted by Allison Bailes on March 14, 2017
The Internet age has made it easy to find information. Occasionally you can find some that's even true. That's where it becomes helpful to have someone more knowledgeable than yourself to be able to ask for advice and input on stuff you read online, get feedback on ideas you'd like to try on a...
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The HVAC design process begins with a load calculation.
Posted by Allison Bailes on March 7, 2017
Here's a little conundrum for you. To get the right amount of heating and cooling to each room in your home, you need a load calculation. Rules of thumb don't work. But if you do a load calculation, the result isn't the size of air conditioner, heat pump, furnace, or boiler you need. It's only the...
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A plastic film with amazing radiative cooling capacity
Posted by Allison Bailes on February 21, 2017
When it's hot out, we want cold. At night, we like to be able to turn on the lights. During the daytime, it can be hard to find the darkness. All these things — hot and cold, light and dark, day and night — can seem like opposites. Chinese philosophy suggests, however, that these opposing forces,...
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Buried ducts in attic insulation
Posted by Allison Bailes on February 16, 2017
Are you confused? In my last article, I said buried ducts are at risk for condensation. Now I'm telling you they'll be allowed in the 2018 code. What's going on here? The answer is simple. Yes, when you bury ducts in attic insulation in a humid climate, you increase the risk of water vapor...
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Condensation on the insulation jacket of a duct running through a crawl space
Posted by Allison Bailes on February 14, 2017
Water vapor from the air condenses on air conditioning ducts in humid climates. It's as normal as poorly insulated bonus rooms making occupants uncomfortable or cigarettes causing lung cancer†. Condensation on ducts is most common in crawl spaces and basements, where the air is more likely to have...
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This heat recovery ventilator is inside the building enclosure
Posted by Allison Bailes on February 10, 2017
If you've been hanging around here for a while, you know I encourage architects and builders to find a way to get the ductwork and heating and cooling systems inside the conditioned space of a home. In cold climates, this usually happens without much argument. In hot and warm climates, we're not...
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ventilation energy enthalpy recovery ventilator erv humidity
Posted by Allison Bailes on January 25, 2017
"You know where this is going, right? Codes will eventually require balanced ventilation." I've heard people say this more than once in the past year or so. As someone who has been attending the semiannual meeting of the ASHRAE 62.2 committee, I've been skeptical. Then I read the new Aspen energy...
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Aspen, Colorado energy code
Posted by Allison Bailes on January 24, 2017
The city of Aspen, Colorado has bucked the trend. Well, actually two trends, but first things first. The 2015 International Energy Conservation Code (IECC) introduced another pathway for code compliance using what's called the Energy Rating Index (ERI). Since the only thing that qualifies as an ERI...
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