Peter Yost is the Residential Program Manager for BuildingGreen, LLC in Brattleboro, Vermont. He has been building, researching, teaching, writing, and consulting on high performance homes for more than twenty years. His expertise stretches from construction waste management and advanced framing to energy efficiency and building durability. Peter has made significant contributions to the work of many leading homebuilding organizations and initiatives — NAHB Researcher Center, Building Science Corporation, 3-D Building Solutions, EEBA, Masco's Environments for Living program, USGBC's LEED for Homes program, and the US Department of Energy's Building America program. Peter is currently an instructor for the Boston Architectural College's Sustainable Design Certificate program and for the University of Massachusetts Department of Building Materials and Wood Technology program in Amherst. He is a past co-chair and current Materials and Resources Technical Advisory Steering Committee member of the USGBC's LEED for Homes program.
Recent Entries by this Author
There are more than 20 different standardized tests manufacturers can invoke to "qualify" as a code-accepted weather-resistive barrier (WRB); with our GreenSpec section on WRBs, we've picked just one that we think does the job.
It's not easy being a weather-resistive barrier (WRB): it has to stop liquid water, be tough and not tear, but also be flexible to wrap around building elements. And it often needs to be vapor-permeable to promote drying.
Finally, water-tight standards
In the past, manufacturers could cherry-pick the standardized test to use to "qualify." That's how we ended up with industry acceptance of perforated and cross-woven housewrap that literally leaks like a sieve.
Now we have a new ASTM "Standard Specification for Vapor Permeable Flexible Sheet Water-Resistive Barriers Intended for Mechanical Attachment." This standard also aligns with the latest version of the ICC-ES Acceptable Criteria (AC) 38–"Acceptance Criteria for Water-Resistive Barriers (PDF)." The table below presents the requirements for WRBs used in the new standard and now by GreenSpec.
Letting short-term payback analyses drive economic decisions about high-performance buildings is crazy.
If we let simple or even net-value payback analysis alone drive the economics of high-performance buildings, we might as well throw in the towel. It is truly crazy to apply just this approach to long-lived durable goods, such as homes. Yes, it is critical that the lower operational costs are factored into a home's value. But homes deliver their value over time to a series of owners. The initial owner or renovator needs to know that all those involved in the financial process will recognize their investment in high performance. And they need to be certain it will fully transfer when they eventually sell their green home.
There are three key housing industry sectors that need to step up to the plate to support our green building industry: realtors, appraisers, and lenders.
Green realtors
Realtors have more contact time with homebuyers than any of us. They build a relationship with their clients, and while they do not have to be knowledgeable about green or high-performance attributes of homes, it's a huge leg up if they are.
Should you replace your old windows? Using attachments can get more life out of them, and improve performance.
Most of us approach poorly performing old windows with a step-by-step exploration from one less-than-optimal fix to the next. Improving existing window performance shouldn't be that way, and it doesn't have to with new online resources.Home Sweet Home
In 2000, my wife and I moved into a nearly 100-year old home in New England, equipped with the original wood single- paned double-hung windows. These windows were supported by some pretty typical window attachments: triple-track exterior aluminum storm windows and opaque vinyl interior roller shades.By and large, the windows themselves operated pretty well. All the sashes raised, lowered, and locked (more than you can say for a lot of 100-year-old windows). But the storm windows and roller shades were another story.
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.
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.).
EPA's new specification for water-efficient homes works well for all sorts of builders and even remodelers
Although EPA's criteria for WaterSense labeled new homes were only recently released, custom and production builders from Georgia to Arizona, from Montana to Hawaii, are signing up. With typical overall water savings of more than 20 percent compared to other homes, WaterSense homes are just that--sensible.A custom builder (and remodeler) perspective
"Water is the next big issue," says Bill Christopher, Secretary/Treasurer of ILM Design and Build, Inc in Wilmington, North Carolina. "While the energy issue is sucking the air out of the room--and there is nothing really wrong with that--we should be paying just as much attention to water."
Welcome to our new blog dedicated to the issues of water, water efficiency, and water policy.
When we talk about the environment and environmentally responsible building, it’s almost always energy that takes the spotlight, with water pretty far down the list. But it’s not hard to see just how much of a back seat driver water can be:
- Water and sewer infrastructure costs: We don’t have any substitutes for clean water and we use a ton of it every day. Actually, more like a ton and a half; the typical U.S. household uses 400 gallons of water a day and that’s about 3,200 pounds! (Source: EPA WaterSense)
- Impact fees: Even in areas of the country with long histories of more than 40 inches of precipitation a year, we can be just a few short years away from not enough water to support our needs. Atlanta averages more than 50 inches of rain a year but it was just a few short years ago that Atlanta was experiencing a severe prolonged drought. (Source: US Drought Monitor)
- Water rates: In many areas of our country, the connections between water and energy are deep—in the state of California, more than one-sixth of all energy consumed is related to meeting water demands. Nationwide, about 80% of municipal water processing costs are for electricity. (Source: Center for Sustainable Systems)
Ever since the premier of USGBC's two-day REGREEN workshop in Phoenix, AZ at Greenbuild last November, Annette, Rob, and I have been gearing up for a slew of green remodeling workshops across the country -- the REGREEN Roadshow. The REGREEN workshops are a lot of fun to teach (and take) for two reasons: one, the blend of builder/remodeler with interior design perspectives is completely refreshing; and two, the substantial and substantive group work woven into the workshop makes for an energetic and invigorating approach.
Now you might be saying to yourself: What? Interior designers and hard-core building science-builder types making sweet music together? You would be surprised at how well these perspectives can inform each other. Here is just one example:
Your clients TELL you they want new replacement windows. But what they actually want is to keep the way their windows currently look, not spend too much, and get real performance improvements (in terms of energy efficiency, thermal comfort, and daylighting -- without overheating during the summer). Whew. So you sit down with an interior designer, and all of the sudden you need to compare about a dozen options -- sash replacements, window films, cellular shades, awnings, shutters -- all with real (but different) advantages. What started as a rather simple choice ends up to be quite a puzzle, based on a weaving of sometimes competing aspects: energy efficiency, lighting, views, privacy, cost, comfort, even noise. It's just as much about interior design as it is hard-core remodeling.
By Peter Yost and Allyson Wendt, posted live from Greenbuild.
It's common knowledge that green building is anything but affordable. Or is it? You would have had a pretty hard time convincing the 100 or so folks at the USGBC's Affordable Housing Summit. They are convinced that green is actually affordable, both in terms of investment and operations budgets.
Heather Clark — from one of the largest property owners of housing in the U.S., Winn Development — stated that water efficiency improvements alone in 76 of their properties cost only $376,000 and saved them over $1.2 M in the first year! In this case, they were paying the water bills, but even if the retrofits had benefited the tenants directly, saving money is still saving money. And saving water is saving water.
I (Peter) have to confess that if I hear the term net present value one more time in the context of green building, I may pass out.
