The most recent blogs at Green Building Advisor

Rating Windows for Condensation Resistance

Posted on October 12, 2012 by Martin Holladay in Musings of an Energy Nerd

Condensation forms on a surface when the temperature of the surface is below the dew point of the air. During the winter, when the coldest surface in a room is often the window, it’s fairly common to see water droplets or ice on window glass — especially in a room with elevated indoor humidity.

Condensation is more likely to form when indoor relative humidity is high. That’s why it’s more common to see condensation on a bathroom window than a bedroom window.

Good News, Bad News: A Glut of Solar Panels

Posted on October 11, 2012 by Alex Wilson in Energy Solutions

When China dives into a technology, it does so in a big way. Nowhere is this more the case than in photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. (PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.) panel manufacturing, where dramatic growth has not only taken a toll on other manufacturers around the world, but also now threatens its own PV industry through rampant oversupply.

This has significant implications for us here in the U.S. — both good and bad.

How to Insulate and Air-Seal Pull-Down Attic Stairs

Posted on October 10, 2012 by Erik North in Guest Blogs

Pull-down attic stairs are super-sized attic hatches that just beg homeowners to store more stuff in their attic. Besides the air-leakage and insulation problems stemming from having a particularly large hole in your ceiling, pull-down stairs creates a potential storage headache.

For homeowners, a storage problem usually means “not enough space.” For energy auditors, a storage problem means using space that ought to filled with insulation for Timmy’s guitar, his old bike, Legos, his new bike, and the unpacked remains of twelve previous moves.

Looking Through Windows — Part 7

Posted on October 9, 2012 by Roger Normand in Guest Blogs

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the 11th article in a series that will follow their project from planning through construction.]

There’s a popular saying here in Maine — “we’re all set” — to signify that the current situation is perfectly fine.

Window selection had so far been the most time-consuming and vexing aspect of the EdgewaterHaus project. That was all behind us. We had made a final decision on an Optiwin-designed Bieber-manufactured Passivhaus-certified windows.

Getting Into Hot Water — Part 4

Posted on October 8, 2012 by Marc Rosenbaum in Guest Blogs

I've now had a year with the Geyser heat-pump water heaterAn appliance that uses an air-source heat pump to heat domestic hot water. Most heat-pump water heaters include an insulated tank equipped with an electric resistance element to provide backup heat whenever hot water demand exceeds the capacity of the heat pump. Since heat-pump water heaters extract heat from the air, they lower the temperature and humidity of the room in which they are installed. (HPWH). With the exception of the puddle on the floor in July 2011, it has performed consistently.

Its performance has not been thrilling, though. In the summer, it was making hot water at about 0.13 - 0.15 kWh/gallon, with incoming water in the mid-60°Fs and basement air temperature around 70°F. In the winter, with basement temperatures in the low to mid 50°Fs, and incoming water at 50°F or a bit below, this consumption ratio increased to 0.25 kWh/gallon.

The Pretty Good House: A Better Building Standard?

Posted on October 5, 2012 by michael maines in Green Building Blog

The Northeast Sustainable Energy Association (NESEANorth East Sustainable Energy Association. A regional membership organization promoting sustainable energy solutions. NESEA is committed to advancing three core elements: sustainable solutions, proven results and cutting-edge development in the field. States included in this region stretch from Maine to Maryland. www.nesea.org) held its annual meeting in Portland, Maine, on September 15th, 2012. After a day of tours of local sustainably designed projects and some pre-meeting smorgasbord grazing, the meeting started with a round of speeches by board and association directors. (Exciting changes are coming; stay tuned!). Then the meeting continued with the entertainment portion of the evening: a panel-style discussion about the Pretty Good House.

Joseph Lstiburek Surprises Passive House Conference Attendees

Posted on October 4, 2012 by Allison A. Bailes III, PhD in Building Science

At the 2012 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. Conference in Denver, Dr. Joseph Lstiburek gave the keynote address for the opening plenary (or plenum, as Henry Gifford would say) session. His words, clever as always, added some nice historical perspective to what the Passive House folks are doing but also caught some people off guard.

Read on, and I'll tell you more about that.

Designing Homes and Communities That Can Survive a Disaster

Posted on October 4, 2012 by Alex Wilson in Energy Solutions

Some 27 years ago, following a five-year stint as director of the Northeast Sustainable Energy Association (which was then based in Brattleboro), I launched my own company focusing on information about environmentally responsible design and construction.

Looking Through Windows — Part 6

Posted on October 3, 2012 by Roger Normand in Guest Blogs

[Editor's note: Roger and Lynn Normand are building a Passivhaus in Maine. This is the tenth article in a series that will follow their project from planning through construction.]

Enough suspense on windows.

It’s a Bieber! And yes, that’s our final decision. We’ve made a sizable cash deposit and started precise shop drawings for the windows.

Can Switching to a Dual-Flush Toilet Save Heat?

Posted on October 2, 2012 by Erik North in Guest Blogs

First off, my wife just joked that I used a photo of a “male bathroom”: seat up and two rolls of toilet paper.

Regarding the heat savings mentioned in the headline, we'll see... I haven't done the math yet. But it is a minor claim occasionally made alongside the claim that these toilets save water.

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