The most recent blogs at Green Building Advisor

Why Is the HERS Reference Home Based on an Outdated Energy Code?

Posted on February 18, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

The HERS Index is a number that gives you a measure of how energy-efficient a home is. We can debate how relevant that number is or how accurate is the energy model it's based on, but the fact is that it's being used.

From a Leaky Old House to a Tight New Home

Posted on February 17, 2015 by Andrew Webster in Green Building Blog

Sara and Gareth Ross had spent a decade on the move. Postgraduate degrees and finance work had propelled them from Boston to New York, Philadelphia, and San Francisco. When it came time to settle down, though, they moved to Amherst, Mass., where Sara had grown up. Amherst is a vibrant college town with rural beauty and Japanese restaurants; for the Rosses, it was the perfect place to slow down, nurture roots, and raise children. The Rosses were not tied either to the idea of a new house or to a remodel.

Why Is It So Humid In Here?

Posted on February 16, 2015 by Scott Gibson in Q&A Spotlight

From the sound of it, Andy Chappell-Dick has left no stone unturned in his quest to keep the air inside his house comfortably dry.

His extremely tight new house in northern Ohio (Climate Zone 5) is built with structural insulated panels, and heated and cooled with a pair of ductless minisplit heat pumps. For ventilation, Chappell-Dick has a Venmar Kubix heat-recovery ventilator(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. that pulls exhaust air from two small bathrooms and supplies fresh air to two upstairs bedrooms with a flow rate of between 40 and 80 cubic feet per minute (cfm).

The Evolution of Superinsulation

Posted on February 13, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

At the recent “Better Buildings By Design” conference in Burlington, Vermont, I attended presentations that epitomized two different approaches to energy-conscious building. I’ll call these two approaches “classic superinsulation” and “the net zeroProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines. Calculating net-zero energy can be difficult, particularly in grid-tied renewable energy systems, because of transmission losses in power lines and other considerations. approach.”

The “classic superinsulation” method has been around for about 35 years. It’s the approach that formed the basis of Wolfgang Feist’s PassivhausA 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.

Passive House Perfection

Posted on February 12, 2015 by Justin Pauly in Green Building Blog

After both growing up in California, Mica and Laureen lived together in many other places throughout their busy careers. Their hearts have always been on the West Coast, though, and they longed to return one day. They eventually found a small piece of property in the coastal enclave of Carmel-by-the Sea on the Monterey Peninsula, and they hired me as architect and Rob Nicely of Carmel Building & Design as builder for a new house that will one day be their permanent home.

New Mexico Develops Innovative Water Efficiency Rating Score

Posted on February 11, 2015 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

Energy usually gets top billing in the green building community. It has a huge impact on the environment. We sometimes pay a significant amount for it (although most of us don't pay enough to motivate serious change, but that's another story). We can do energy modeling and home energy ratings. Plus, it's just really interesting!

Convincing Clients to Upgrade to Pretty Good (or Better)

Posted on February 10, 2015 by michael maines in Guest Blogs

How do you convince clients to upgrade from code-minimum (or worse) construction to Pretty Good House, or better, levels of performance?

How do you ventilate a commercial-style range in an airtight house?

If your house was a car, what kind of car would it be?

What do these questions have in common? They were all discussion points at a December 2, 2014 conference in Maine, co-hosted by the Maine Indoor Air Quality Council (MIAQC) and the Maine Association of Building Efficiency Professionals (MABEP).

Attic-Insulation Upgrade

Posted on February 9, 2015 by Mike Guertin, GBA Advisor in Green Building Blog

Do you want to keep your heating costs from going through the roof? It’s easy: Keep your heat from going through the roof. Saving money on heating-fuel costs is a lot simpler than negotiating with OPEC or your local utility. On a recent upgrade in the attic of a 1950s-era house (one of two projects shown here), I air-sealed and spread a 12-in.- deep layer of cellulose throughout 1500 sq. ft. of space in about a day.

Split-System Heat-Pump Water Heaters

Posted on February 6, 2015 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

Heat-pump water heaters are a type of air-to-water heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump.. Almost all heat-pump water heaters sold in the U.S. extract heat from the air in the room where the water heater is located, transferring the heat to water in an insulated tank.

Insulating an Old Brick Dormitory

Posted on February 5, 2015 by Oliver Klein in Guest Blogs

Countless historic masonry buildings dot the American landscape, a large number of them falling under some form of aesthetic scrutiny prohibiting exterior insulation. The only option to make these buildings energy-efficient is to insulate them on the interior.

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