The most recent blogs at Green Building Advisor

Proper Sizing Isn’t the Real Reason for HVAC Design

Posted on May 9, 2018 by Allison A. Bailes III, PhD in Building Science

Many people seem to think HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. 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).

But there's so much more to real HVAC design than simply finding out how much heating and cooling a building needs when it's at design conditions. And we might as well start with the fact that my first statement is incorrect: The load calculation does not tell you what size system you need.

Market Forces Are Driving a Clean Energy Revolution

Posted on May 8, 2018 by Bill Ritter in Guest Blogs

Transforming U.S. energy systems away from coal and toward clean renewable energy was once a vision touted mainly by environmentalists. Now it is shared by market purists.

Today, renewable energy resources like wind and solar power are so affordable that they’re driving coal production and coal-fired generation out of business. Lower-cost natural gas is helping, too.

Frugal Happy: A Car-Free Experiment

Posted on May 7, 2018 by Chris Stratton and Wen Lee in Guest Blogs

Editor's Note: This post is one of a series by Chris Stratton and Wen Lee, a husband-and-wife team living in the Los Angeles area who are turning their suburban house into an all-electric, zero-net energy home. They chronicle their attempts at a low-carbon, low-cost, and joyful lifestyle on their blog Frugal Happy. This post was written by Wen.

Another Perspective on Air-to-Water Heat Pumps

Posted on May 4, 2018 by Martin Holladay in Musings of an Energy Nerd

Green builders, preparing for a fossil-fuel-free future, are busy building all-electric homes. Most of these homes are heated and cooled by minisplit heat pumps. Occasionally, though, a builder who’s worried about uneven heat distribution in a home with ductless minisplits will post a question on GBAGreenBuildingAdvisor.com suggesting the use of an air-to-water heat pump hooked up to a hydronic distribution system.

How Texas Is Building Back Better From Hurricane Harvey

Posted on May 3, 2018 by Nicole Errett in Guest Blogs

For most Americans, the one-two punch of last fall’s hurricanes is ancient history. But hard-hit communities in Texas, Florida, and the Caribbean are still rebuilding.

Using Energy Modeling to Get to Zero

Posted on May 2, 2018 by Bruce Sullivan in Guest Blogs

A computerized energy model is an essential element of building design for high-performance homes, because it allows the designer to predict the energy performance of a building based on specific site characteristics, structural assemblies, mechanical efficiencies, and renewable technologies. By adjusting these elements of building performance, the designer can choose the most cost-effective combination of features. While models are just predictions — and therefore will never be completely accurate — skillful use of a modeling tool should lead to more affordable, energy-efficient buildings.

Flatrock Passive: Framing and Insulating an Interior Service Wall

Posted on May 1, 2018 by David Goodyear in Guest Blogs

Editor's Note: This is one of a series of blogs by David Goodyear describing the construction of his new home in Flatrock, Newfoundland, the first in the province built to the Passive HouseA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates. standard. The first installment of the GBAGreenBuildingAdvisor.com blog series was titled An Introduction to the Flatrock Passive House. For a list of Goodyear's earlier blogs on this site, see the "Related Articles" sidebar below; you'll find his complete blog here.

Details for a Closed Crawlspace

Posted on April 30, 2018 by Scott Gibson in Q&A Spotlight

Emerson has moved into a house in Climate Zone 4A, a region where humidity can be relatively high. As Emerson explains in a Q&A post, the crawlspace beneath part of the house has been closed to the outside, and now the question is how to insulate the space to help keep the house comfortable.

Bruce Harley’s Minisplit Tips

Posted on April 27, 2018 by Martin Holladay in Musings of an Energy Nerd

Bruce Harley is a Vermont energy consultant and heat-pump specialist. To GBAGreenBuildingAdvisor.com readers, he is probably best known as the author of the Taunton book, Insulate and Weatherize — one of the best available books on residential energy retrofit work.

Understanding and Measuring Mean Radiant Temperature

Posted on April 26, 2018 by Peter Yost in Building Science

All the way back in 1993, one of my first research projects at the NAHBNational Association of Home Builders, which awards a Model Green Home Certification. Research Center was assessing the performance of radiant ceiling panels for the Department of Energy’s Advanced Housing Technology Program. (The final report was titled “An Evaluation of Thermal Comfort and Energy Consumption for the Enerjoy Radiant Panel Heating System.”)

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