The most recent blogs at Green Building Advisor

Why a Vermont Utility Welcomes Solar

Posted on March 7, 2016 by Mary Powell in Guest Blogs

The world of energy is filled with new promise — promise for a cleaner, greener, more cost-effective distributed future. But, alas, in a world where for generations utilities have done the same thing in the same way, change is being hampered by our industry and is moving too slow.

Tales From Armenia

Posted on March 4, 2016 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

In this week’s blog, I’m going to take a break from building science. Instead of providing advice to green builders, I’m simply going to reminisce about my time as a construction volunteer in Armenia.

Corn Ethanol: The Rise and Fall of a Political Force

Posted on March 3, 2016 by Tristan Brown in Guest Blogs

The 2016 presidential primary race is defying conventional wisdom, with erstwhile fringe candidates competitive in the polls despite their unorthodox policy positions. The Iowa Republican Caucus provided additional material for this storyline as Senator Ted Cruz defied projections and won the state.

His victory came despite his opposition to subsidies for one of the state’s biggest industries: the production of corn ethanol.

Those results would have been unthinkable just a decade ago, when American policymakers wanted to see as much corn ethanol consumed as rapidly as possible.

Rebuilding a Mid-Century Dinosaur

Posted on March 2, 2016 by Carri Beer and Michael Hindle in Guest Blogs

Editor's note: Carri Beer and Michael Hindle are renovating this 1954 house in Catonsville, Maryland. Hindle is a Certified 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. Consultant and owner of Passive to Positive. Beer is a registered architect who has been practicing sustainable architecture for 18 years. She is an associate principal with Brennan+Company Architects. This is the couple's first in a series of blogs about the project.

The Supreme Court Saves the Smart Grid

Posted on March 1, 2016 by Seth Blumsack in Guest Blogs

In a surprising 6-2 decision, the Supreme Court upheld a controversial energy conservation rule from the Federal Energy Regulatory Commission (FERC), the agency that regulates interstate electricity sales.

Is This Ground-Source Heat Pump Plan Workable?

Posted on February 29, 2016 by Scott Gibson in Q&A Spotlight

Jordan Garrow is getting ready to build a new house in New York State, on the cusp between Climate Zones 5 and 6, and he's planning to heat and cool it with a ground-source heat pumpHome heating and cooling system that relies on the mass of the earth as the heat source and heat sink. Temperatures underground are relatively constant. Using a ground-source heat pump, heat from fluid circulated through an underground loop is transferred to and/or from the home through a heat exchanger. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps; ground-source heat pumps also perform better over a wider range of above-ground temperatures.. His contractor wants to install a horizontal "slinky loop" heat exchangerDevice that transfers heat from one material or medium to another. An air-to-air heat exchanger, or heat-recovery ventilator, transfers heat from one airstream to another. A copper-pipe heat exchanger in a solar water-heater tank transfers heat from the heat-transfer fluid circulating through a solar collector to the potable water in the storage tank., one of several possible options, and Garrow is seeking a second opinion.

A heat load calculation for the house specifies a 4-ton system (one with a capacity of 48,000 BtuBritish thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature—about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules. /hour), but the contractor wants the heat exchange loops designed as if they were serving a 6-ton system.

Combining Exterior Rigid Foam With Fluffy Insulation

Posted on February 26, 2016 by Martin Holladay, GBA Advisor in Musings of an Energy Nerd

It’s becoming increasingly common for builders to install one or more layers of rigid foam on the exterior side of wall sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. and roof sheathing. Typically, these walls and roofs also include some type of air-permeable insulation (fiberglass, cellulose, or mineral wool) between the studs or rafters.

The Cheapest Way to Scale Up Renewable Energy?

Posted on February 25, 2016 by Christopher Clack in Guest Blogs

Generating electricity with wind turbines or solar arrays instead of fossil fuel reduces carbon emissions, but these renewable generation sources are dependent on the vagaries of the weather, which means neither wind nor solar can produce electricity on demand at all hours of the day. This variability has ledLight-emitting diode. Illumination technology that produces light by running electrical current through a semiconductor diode. LED lamps are much longer lasting and much more energy efficient than incandescent lamps; unlike fluorescent lamps, LED lamps do not contain mercury and can be readily dimmed. many to assume that greatly expanding wind and solar to reduce carbon emissions will cause electricity costs to skyrocket and require expensive energy storage.

What Is the Ideal Relative Humidity in Winter?

Posted on February 24, 2016 by Allison A. Bailes III, PhD, GBA Advisor in Building Science

It was a little crackly around here recently. We had a cold spell in Atlanta, with high temperatures right around the freezing point. As a result, the indoor relative humidity dropped and we got some static electricity.

Even better, what I call the Southern Lights were visible at night, too. (I've never called it that before, but hey, a man named Allison is entitled to make things up on the spot.) That's when the microfiber blanket on the bed lights up every time I move.

Blue Heron EcoHaus: Picking High-Performance Windows

Posted on February 23, 2016 by Kent Earle in Guest Blogs

Editor's note: Kent Earle and his wife, Darcie, write a blog called Blue Heron EcoHaus, documenting their journey “from urbanites to ruralites” and the construction of a superinsulated house on the Canadian prairies. Their previous blog on GBAGreenBuildingAdvisor.com was called How Small Can We Go? The blog below was originally published in May 2015.

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