As I always do when I fly, I bring my own stainless-steel water bottle, finishing the contents before going through security, then filling it so that I don't need a plastic water bottle from the flight attendant. When I flew out of O'Hare in Chicago to return home from a meeting the other day, for the first time I filled my bottle from a new Elkay EZH2O bottle filling station.

It's much more convenient. Unlike filling from a standard drinking fountain, it only took one hand, so I didn't have to contort my body to keep my computer bag from slipping off my shoulder as I stooped over and waited for my bottle to fill. It's a lot faster, with a 1.1 gallon-per minute (gpm) fill rate--close to three times that of a standard drinking fountain. And I didn't have to keep raising and lowering the mouth of the bottle to keep the water flowing in as the pressure changed and the stream rose and fell.

Mostly I like the new bottle-filling station for the environmental benefits of avoiding the use of plastic water bottles. Consider: [More]

Last week, after reviewing a little physics regarding condensation and latent heat, I described how air conditioners remove unwanted humidity. This week I'll examine how dehumidifiers work in removing moisture and when it makes sense to use them. Like air conditioners, dehumidifiers remove moisture by condensing water vapor out of the indoor air. While an air conditioner dumps the warm air that's produced through that condensation process (latent heat) outdoors, a dehumidifier doesn't get rid of that heat. Instead, releases the warm air into the space where it's is located. [More]

The U.S. Green Building Council (USGBC) has now released several sets of LEED addenda for LEED-EBOM 2009—corrections and changes to the rating system since its official release. The earliest of these start in November 2009, and the latest batch came out in July 2010.

Following is a summary of the more useful LEED-EBOM addenda to date. Most of the rest is less critical to project teams unless you need clarification on things like understanding that "includesincludes" on page 23 of the Reference Guide really means "includes."

• Janitor sinks out. WEp1 no longer includes janitor sinks.
[More]

Wasco Products of Sanford, Maine, has raised the bar on energy-conserving skylights with its high-performance "Triple Glazed 30/30" option. In a fixed skylight, this glazing provides a unit U-factor of 0.27, or a unit R-value of 3.7; in the venting skylight, a unit U-factor of 0.29 (R-3.4). (Note that the "unit" R-values, which account for heat loss through the frame and glazing edges, are a lot lower than "center-of-glass" R-values--but much more accurate in conveying actual performance.)

Both fixed and venting options provide a Solar Heat Gain Coefficient (SHGC) of 0.22, meaning that just 22% of the total solar energy striking the glass gets through.

To provide a little context, the "30-30" designation on a window or skylight refers to a performance requirement developed for the current round of federal tax credits in which both the total unit U-factor and SHGC can be no higher than 0.30. With such a designation, windows can earn the $1,500 federal tax credit through the end of 2010. [More]

Last week, I addressed strategies for controlling moisture sources in homes during the summer--one of the contributors to discomfort during hot humid summers. This week, I'll examine how to remove unwanted humidity using air conditioning equipment, starting with some fundamentals. To understand moisture removal, it's important to brush up on a bit of physics. Air is able to hold only a finite amount of water vapor, and that amount is governed by the temperature of the air. Warm air can hold more moisture than cool air. This is why water droplets appear on that cold glass of iced tea: the outer surface of the glass is cold so the air close to the glass cools off and the amount of moisture it can hold drops. When that air temperature cools to the "dew point," it means that 100% "relative humidity" is reached; as it cools further, water vapor in that air "condenses" out as liquid water. (Relative humidity is the amount of water vapor in air, expressed as a percentage of the total amount of water vapor that air could hold at that temperature.) [More]

A German system for reducing thermal bridging in commercial construction looks like a real winner.

In commercial buildings where cast-in-place, reinforced-concrete balconies extend through the insulated building envelope, tremendous heat loss occurs, and this thermal bridging often leads to condensation and associated mold problems. The German company Schöck Bauteile, GmbH, has the answer with the Isokorb product line.

How Isokorb works

For thermal breaks in cantilevered slabs (such as with balconies in high-rise residential buildings), Isokorb K provides an expanded polystyrene (EPS) layer of insulation--either 80 or 120 mm (3.1 or 4.7 in) thick--with carefully engineered steel re-bar passing through it to carry the loads. The Isokorb module includes both straight pieces of re-bar at the top that function in tension and specially bent re-bar that functions in compression to maintain the strength that is lost by substituting EPS for some of the concrete (see illustration showing loads and forces). [More]

High relative humidity is a significant problem in many regions of the country during the summer months. In hot weather, the higher the humidity, the less comfortable we are--partly because moisture does not evaporate from our skin as readily. More worrisome over the long haul, high humidity levels in the air and high moisture content of materials in our homes can result in mold growth, which, in turn, can cause allergies and other health problems (as well as damage the building itself). There are two broad strategies for minimizing indoor humidity problems during the summer months: eliminating moisture sources, and removing moisture from the air. This week we'll take a look at controlling moisture sources; next week we'll examine moisture removal. Keeping moisture out of a home is almost always less expensive and less energy-intensive than removing that moisture. [More]

A new gas-filled panel insulation material that consists of pockets of low-conductivity gas in a honeycomb foil substrate provides insulation levels as high at R-11 for inch-and-a-half-thick panels.

About gas-filled panels

It is well-known that low-conductivity gasses, such as argon and krypton, significantly improve the energy performance of windows. They do this because they have a lower gas-phase conductivity than air, so they retard heat flow through the window.

Researchers at Lawrence Berkeley National Laboratory (LBNL) have long argued that this same principle could be used to create high-performance building insulation, and they developed technology for encapsulating gasses in flexible foil and plastic honeycomb material. LBNL licensed this technology to the radiant barrier manufacturer, Fi-Foil, which introduced a gas-filled panel (GFP) insulation material at the International Builders Show in January of this year. [More]

You would think that establishing a definition for “showerhead” would be simple. But, as the Department of Energy (DOE) is discovering after issuing a draft interpretive rule on the matter, nothing is simple when it comes to getting people wet.

Some showerhead background
Back in early 1994, under the Energy Policy and Conservation Act (EPCA) of 1975, all showerheads manufactured in the U.S. could have a maximum flow no greater than 2.5 gallons per minute (gpm) at 80 psi. The intent, of course, was to save water, particularly hot water and its associated energy use.

Over the years, plumbing manufacturers have gotten pretty creative about how people can get wet in their showers or baths. In recent years, the trend has been toward “multi-spray” systems, which have up to six “showerheads” (each of which complies with the 2.5 gpm flow maximum) and “waterfalls,” which aren’t really “showerheads” and therefore aren’t subject to the requirement (see photo: this Kohler shower system has 8 separate showerheads, each one complying with the 2.5 gpm maximum). These systems can use up to 20 gallons of water per minute, just for one person. And even though the actual installation number for these DOE-dodging plumbing fixtures is relatively low, they represent an important, high-end product for plumbing manufacturers. [More]

We're into those hot days of summer--really hot--with temperatures predicted in the mid- to upper-90s, even in Vermont, this week. In this column I'll provide some simple tips for keeping (reasonably) cool in hot weather or, if you use air conditioning, operating that air conditioning equipment most efficiently. Keep the sun out Shading windows is the easiest way to keep your house cool or keep your air conditioning bills down. Pulling down interior window blinds will help (the more reflective the outer surface of the blinds the better), but shading is even more effective if you can block the sunlight on the outside of your windows. In Europe, exterior roller blinds are often used, and these are beginning to catch on here, but they're not yet widely available. I've improvised exterior shading on a wide patio door facing west by propping up a tarp on the outside of the door, and that makes a huge difference. Climbing vines on a trellis, nearby trees, large potted plants that can be rolled in front of doors or windows, and awnings can also help a lot. If there's no way to block that sunlight on the outside of windows and patio doors, install and use interior blinds. [More]

The July 2010 issue of Environmental Building News asks whether we should end our love affair with all-glass buildings. The short answer is "yes." With most large commercial buildings there is an energy penalty associated with increasing the glazing area beyond 20 to 30 percent. Given today's glazing technologies, it does not make sense to create highly glazed buildings. That is especially the case with "green" buildings, where extra effort is being made to reduce energy consumption and environmental impact.

The energy penalty of more glazing

In researching and writing this article, "Rethinking the All-Glass Building," I got energy modeling support from Fiona Cousins, P.E., Scott Bondi, P.E., Ph.D., and Cameron Talbot from the New York City office of Arup, one of the world's leading engineering firms. I used that data to make the case that highly glazed façades don't make sense from an energy standpoint. [More]

One of Vermont's longest and most treasured covered bridges now has the newest, most environmentally responsible lighting. This past weekend, the 267-foot West Dummerston Covered Bridge (the longest operating covered bridge fully within Vermont), built in 1872 by Caleb Lamsom and listed in the National Register of Historic Places, was fitted with state-of-the-art LED lighting. Ten new fixtures replace very old high-pressure sodium (HPS) fixtures. Those of the older units that were still working at all (see photo of fixtures that were removed) had greatly reduced output and resulted in poor visibility in the bridge. While some people might have liked the dim, warm-yellow light that the aged HPS lights provided, the efficacy (lumens per watt) of that lighting was horrible. Despite the very low light output, each of the HPS fixtures was still using 100 watts of electricity as much as 17 hours per day. (Both old and new lights are controlled by a photosensor that turns them off when outside light levels are high enough.) [More]

North America's largest water heater manufacturer, A.O. Smith, is shaking up the water heating industry with its NEXT Hybrid gas-fired water heater that combines key features of both tankless and storage water heating technology.

About storage water heaters

As a refresher, storage water heaters have relatively small burners (in the case of gas-fired models) and large, insulated storage tanks. The water is heated gradually and stored in the insulated tank until needed. The advantage is that the burner can be small, keeping the gas supply pipe small and the air supply and venting needs relatively low. [More]

Pressure-reducing valves, an element of EPA’s WaterSense® new homes specification, are green: they can save water, increase the service life of plumbing system components, and reduce risks of water leaks.

What is a Pressure Reducing Valve (PRV)?
PRVs have spring-loaded diaphragms that resist the incoming pressure of the water supply to a home. They are typically installed just after the water meter on the system side (see top photo: This basement photo, starting from the bottom, shows the insulated incoming water main, the single-throw main shut-off (red handle), the water meter, and the pressure reducing valve (set screw stem sticking out to the right). PRVs usually come set at 45 pounds per square inch (PSI) but have a set-screw adjustment so that the PRV’s range of operation is from approximately 30 to 80 psi. PRVs cost around $80; installation costs may double the total cost, depending on installation circumstances (new or existing home, location of incoming line, ease of shutting off water service to the home, etc.). [More]

While our homes and cars get most of the attention relative to energy savings, our materials stream also has a huge impact on energy use. Nationally, the U.S. generates about 236 million tons of municipal solid waste each year, according to the U.S. Environmental Protection Agency. That works out to about 4 pounds of waste for every American every day. Recycling our waste saves a lot of energy. Just how much depends on the material. With very energy-intensive materials, like aluminum, carpeting, and copper, a phenomenal amount of energy is saved because the new materials take so much energy to produce. Recycling just one ton of aluminum cans saves 209 million British Thermal Units (Btu), according to EPA; with 5.8 million Btu in a barrel of crude oil, that's equivalent to 36 barrels of oil. [More]