In our series on passive houses this week, we’ve discussed the merits of saving energy by using condensing driers, of tightly insulating homes to achieve super-efficient energy standards, and we’ve talked about the general merits of building a passive house.  One of the things we’re also interested in are examples of passive buildings – of homes built in the U.S., as well as passive homes, schools, and office buildings built around the world.

As the New York Times reports, there are currently 25,000 passive house-certified buildings in Europe.  In the U.S., however, there are only 13.  While passive design in Europe is well-established – tested by time, certainly (the first homes were built in 1990) – the standard has taken longer to catch on the in United States.  Materials rated efficient enough for the standard are more difficult to find here, and designers who are certified in, and understand well, the criteria are few and far between.

This is not to say, however, that people in the United States haven’t risen to meet the challenge of passive house construction.  Our mention of the Habitat for Humanity home proves as much.  The Times article on the Landau home does, as well.

image courtest of root design build

One of the first homes in the U.S. built to the standard was Shift House, in Portland, Oregon.  As the Williamette Week wrote last year, the Shift House was designed not only to meet the stringent standards of Passive House certification, but was also deliberately designed to be highly aesthetically-appealing.   Another unique aspect of the Shift House was its use of an 8-inch-thick structural insulated panel, or SIP, that acts as the primary pressure envelope for the house.  Even other passive houses in the U.S. don’t utilize this technology or this emphasis on design – proving that even for architects and contractors, there are a variety of materials and techniques available to build passive homes.  Green Depot offers some of those materials in the green building materials department.

While in the U.S. we might only have 13 existing structures, in 1997 there were only ten passive houses in existence in Germany, where the standard was first invented.  The current record of 25,000 European passive buildings then represents an enormous and astonishing leap forward.  But in Europe, it is not only residential houses that have been built to the passive standard.

neue burse residential hall. image courtesy passiv haus institut.

Case in point: the Neue Burse residence hall, or dormitory, located at the University of Wuppertal in Wuppertal, Germany.  The building, which was originally constructed in 1977, was deemed to be a massive energy sink that required significant amounts of energy to keep in operation.  It was decided to refurbish and retrofit the building to passive standards.  Construction was completed in 2003, and represents the largest residential building in Germany to comply with the passive house standard.

social housing in kassel marbachshoehe. image courtesy of passiv haus institut.

In Kassel-Marbachshohe, city officials undertook the ambitious project of ensuring that their next public housing development meet the passive standard.  While building specific-user residential homes on empty lots provides the architect with a significant degree of free in designing a home for energy efficiency, designing in tight urban spaces offers new challenges.  Despite this, however, 40 residential units in a multi-story complex were constructed using public funds, and the building was able to meet an 82% increase in energy efficiency over conventional construction (page in German).

office building sportplatzweg. image courtesy hermann-kaufmann architects.

In 1999, the German architecture firm Hermann-Kaufmann designed an architectural office space to passive standards (page in German).  As described on their project page, the building experiments with new materials: the staircase is covered with fabric, and the base of the building is covered with painted oriented strand board (OSB).  The Office Building Sportplatzweg, situated on an open expanse, is a brilliant example of how architectural design can be both ecologically-sound and blend beautifully with the surrounding landscape.

While these buildings do provide valuable examples of the tried-and-true design philosophy of passive house criteria, it is still somewhat disheartening that only thirteen examples exist in the United States.  Consider, though, that presently 160 architects have been trained as passive-house designers, and that that number is expected to rise to 300 by the end of the year, and the picture looks less bleak.

The more awareness that is made of this certification system, and the more the government begins providing tax rebate incentives for passive house construction (in the same way the government already does for LEED or Energy Star construction), the brighter the future of truly energy-efficient passive buildings in the U.S. looks.

Visit Green Depot to get more ideas on building materials and green products to make your home more environmentally-friendly.

A passive house in Austria. Image courtesy the Passive House Institute.

One of the main principles of passive house construction (read about this fantastic energy-saving way of building in this recent New York Times article) is making the building envelope as close to airtight as possible–to keep heat and cold from leaking in and out where they’re not supposed to. Several construction techniques unique to passive house design help achieve that goal, most notably the principle of keeping the inside and outermost layers of the house detached from the framework studs so they don’t have to be punctured for screws. But special construction techniques aren’t the only way to keep your house airtight: If you’re building from scratch, you can reconsider what appliances you’ll be installing, too.

Your clothes dryer (if you even use one) is especially important, because the exhaust vent leading to outdoors a traditional dryer requires typically allows far more air in and out of the house than just the hot air from the dryer. A more energy-conserving option is a condensing dryer. These dryers dispose of hot, damp air by turning the water in it into condensation and draining it away, then keeping the heat from the air to keep drying the clothes–as opposed to just sending the heat and moisture outside as waste, like a conventional dryer does. And since a condensing dryer doesn’t send anything outside, it doesn’t need a vent—so you don’t have to cut a leaky hole into your house for one!

And while you’re saving energy by installing a condensing dryer in your house, you can save it inside the machine, too. Wool Dryer Balls look like tennis balls, and dropping a few in the dryer with your clothes not only shortens drying time but reduces wrinkling, too. And there are countless green cleaning products for the wash. Among Green Depot’s favorites: Oxy-Boost is a fantastic alternative to chlorine bleach, and Charlie’s Soap Laundry Powder works like a charm without phosphates or fragrances–and comes in a nifty old-timey package, too.

courtesy Passive House Institute U.S.

Earlier this week we wrote about Habitat for Humanity’s first passive house being built in Vermont.  While many readers are perhaps familiar with some of the building standards for LEED or Energy Star certification, we’re also interested in the exact criteria that go into building a passive home.

Passive house certification is certainly the highest energy standard for home building.  As the New York Times notes, a LEED-certified home can be certified as such with only a 15% improvement in efficiency over conventional construction; passive homes are capable of achieving 90% efficiency over conventional homes, and some are even able to return electricity into the grid, netting a negative energy consumption rate.

These homes are well-insulated (nearly air-tight) and heated by passive solar energy – like a greenhouse – and internal energy gains from human body heat or, for example, the heating of a tea kettle.  Achieving this level of efficiency requires exacting design, including the very specific angle of construction towards the sun.  Achieving passive house certification from the Passive House Institute U.S.A. requires a very rigorous evaluation of the home’s energy consumption and insulation.  For a home to be passive, it must be determined to have:

1. a maximum annual heating requirement less than or equal to 15 kWh/(m²a)

2. a pressurization test result with a maximum of 0.6 h^-1

3. an entire specific primary energy demand less than or equal to 120 kWh/(m²a) including domestic energy consumption.

What this means is that the house cannot require heating or cooling demands beyond the specific thresholds detailed above.  Accomplishing this requires super-tight insulation of the home.  To be more specific, the pressure envelope of the home cannot exceed a loss of pressure of 0.6 air changes per hour (the number of times per hour that a room’s total air volume is exchanged with fresh air at 50 pascals), measured by blower-door test – only a minimal amount of air (heated air in the winter) is allowed to escape the home.  This level of insulating efficiency reduces the heating requirement to below the aforementioned threshold, and reduces the level of electrical consumption needed to cool or heat the home.

To read more about passive house certification, you can read Passive House Institute U.S.’s performance characteristics, or read Passiv Haus Insititut’s residential criteria (PDF).

To read more about green insulation options here in the U.S., as well as green products, low-VOC paints, and other eco friendly building materials, you can always visit Green Depot’s homepage.

While it’s one thing (and a great thing) to talk about green building, it’s not every day that we meet people who are actually doing it on a grand scale. So to bring a fresh dose of reality to the conversation, we tracked down someone who not only talks the green talk but is decidedly walking the green walk, too. Here’s a short Q&A session with Thom Woglom, a green contractor in Warwick, New York. Thom is a regular Green Depot customer, and with 25 years of experience as a general contractor, he is now the owner and president of Greenway Technologies of Warwick–a contracting company specializing in green building. He kindly took the time to answer some basic questions about the business for us.

Green Depot: Thom, what are some of the reasons your customers have given for choosing a green contractor and green building materials, as opposed to going the standard route?
Thom Woglom:
Well, the community of Warwick is special in that it’s both very rural and is made up of a lot of progressive thinkers. So there’s a big emphasis on nature here, and preserving it. The environment is very much on people’s minds these days–there’s a huge amount of interest in green products. But beyond that, our company (my son is my lead foreman) is unique in that we also offer an electronics-recycling service to the community–and a lot of our green building customers come to us by way of that. We think the key to expanding the green movement lies within forming a sense of community around it, because the biggest changes are happening within communities and are growing from the ground up. So we provide a service for our community that helps it become more green-conscious, and as an added benefit, it brings our green business new interest and customers.

GD: What are some products you use often that you order from Green Depot?
TW: We use a lot of your National Fiber cellulose insulation, your Solatube ventilation and daylighting systems, and your Complete Radiant subflooring. We’re about to start working on a house that will have all of those products and many more–they client is going all-out, with a rainwater containment and reuse system, a freshwater swimming pool, wind power, and even a Permaculture site design.

GD: That’s fantastic! Hopefully one day every house will be like that… But are there any areas of the house where that client chose a non-green option? And if so, why?
TW: Well, one of the reasons we’ve heard most often from clients when they don’t want to go with a green choice is concerns about reliability. People haven’t seen most of these new green technologies in action over a long enough time to feel 100% comfortable relying on them yet. This client’s way of addressing those concerns was to have a backup to each of the major systems. So in addition to solar power and heating, he’s installing traditional fossil-fueled electricity and a furnace, too, just in case the greener systems fail (which, of course, we don’t believe they will). It’s an interesting approach. Many clients are also put off by the pricing for green systems, which are generally higher than what they find at a mass-market discount warehouse, but might not be too much higher than non-discounted traditional systems. But price isn’t the main concern for this particular client.

GD: What about the installation of green systems–is it any more difficult or easier than installing traditional heating, cooling and insulation?
TW: It’s all in how you think about it. Any new system requires learning something new, but the basic tools and techniques of building and installation stay the same. As it happens, some of the older workers who might be resistant to learning new methods are now aging out of the workforce, and we’re taking the opportunity to teach the new systems to the new generation of workers from the very beginning. But ultimately, regardless of age, if you’re willing to learn and read instructions, green building really isn’t any more difficult.

GD: Thanks for sharing your experience and expertise, Thom!

Thom Woglom and his company are currently building their area’s first interactive showroom for green building and landscaping, which will feature everything from super-insulated windows and low-flow toilets to compost makers and edible landscaping.

With the first rainy days of autumn having arrived in the Northeast, homeowners are beginning to prepare their apartments and houses for the colder weather.  As the days grow shorter and cold, more people will be spending time indoors.  Heating and energy costs will rise, and exposure to household chemicals and other dangerous substances will increase.

Green Depot is fortunate to be able to recommend and supply any number of innovative, safe, and energy-efficient products to help anybody survive the autumn chill as winter hibernation draws ever more near.  This season, we are glad to suggest these nine ideas to make the season more comfortable.

1.  Humidifiers

Home heating systems, whether through radiators or ventilation systems, sucks moisture out of the air and can leave one with dry skin and eyes; dry air can also seriously aggravate respiratory conditions like asthma, bronchitis, sinusitis, and nosebleeds.

Choosing a humidifier isn’t a terribly difficult decision to have to make, but it’s important to ensure the humidifier is antimicrobial so that unwanted bacteria aren’t released into the air.  Green Depot carries multiple models of safe and healthy humidifiers – some of which are Energy-Star rated.  They range anywhere from $49.95 to $199.99.  Click here to see Green Depot’s full catalogue of humidifiers.

2. The Electrolux Ergorapido

The Electrolux Ergorapido is a cordless two-in-one vacuum cleaner that converts from a stick vacuum for cleaning bare floors, to a hand vacuum for spot-cleaning around the home.  There are no bags to buy, since it sucks all of the dirt into a dust cup.  What makes it green?  The Electrolux Ergorapido is deigned to remove dust, particulates, and allergens, helping to clean the air in your home – certainly a more comfortable way to spend the autumn, especially for people with respiratory conditions.

3. Air Filters: Easy Breathing

Air filters come in any number of sizes and styles for a wide range of applications, from purifying the air of allergens, to removing odors and gasses.  In terms of environmental benefits, all of the green products that Green Depot carries are either produced locally, or are energy efficient, or are built by companies that manufacture responsibly.  The Andrea Air Purifier, for example, uses living plants and soil to clean the air of toxic gases such as formaldehyde, and is produced using responsible manufacturing practices.

4. Air and Water Test Kits

Many common household items can be hazardous to the health.  Green Depot recommends visiting the CDC’s National Center for Environmental Health, whose website has a wealth of information on carbon monoxide poisoning, leading poisoning, and other environmental chemicals.  For the individual looking to determine if there are environmental chemicals present in the home, Green Depot offers a full spectrum of home test kits – allowing the homeowner to easily test their house or apartment for mold, pesticides, radon gas, water quality and bacteria, asbestos, lead… the list goes on and on, but the test kits are always available at

5. Insulation

We’ve touted the environmental and personal benefits of insulating your home before, and of course the cool autumn weather is a simple reminder that colder winters are ahead.  Insulating the home saves energy and cost of heating, and Green Depot carries a variety of different insulations – some of which can be shipped  directly to your home, in certain states – all of which has significant health and environmental benefits over standard insulation.

6. Weatherization

We’ve also discussed weatherization in the past.  Filling in the nooks and holes where cold air is let in, and heated air is let out, is an important part of ensuring that the home is energy efficient.  Weatherizing saves energy – benefitting the homeowner’s environmental footprint as well as the pocketbook.

7. Household Cleaners

Using green cleaning products is a sure way to make the household environment healthier for both the people living there and for the earth.  A green home has been tested for allergens, molds, and other hazards like formaldehyde and radon gas.  It uses cleaning products that keep our watersheds clean and safe for marine life.  Green Depot carries whole categories of green cleaning products – tools, recycling containers, cleaners, drain openers, laundry supplies, mold remediation, pest control, reference books, and vacuums.

8. Pest Control: Bed Bug Free

We’ve already discussed the current bed bug epidemic that’s affecting thousands of people in all metropolitan areas – the idea of encountering bed bugs in the autumn is perhaps more troubling than in the summer.  The idea of living in a shuttered autumn home with the incredibly toxic conventional sprays is even more harrowing.  Using an environmentally-friendly and healthy bed bug repellant like Bed Bug Free is a welcome solution for everyone cursed by bed bugs.

9. Door Mats and Boot Trays

Rainy winter days mean wet and muddy boots.  Purchasing a boot tray or doormat is simple enough, but choosing one that is kind on the environment can be trickier.  Green Depot carries two products to address this – a tray made from recycled polypropylene (which doubles as a planter in the summer!) or a recycled lobster rope doormat.  The lobster rope doormat is produced locally, using responsible labor practices, with recycled rope used to tether lobster traps in Maine.

Many of our readers are familiar with the two most popular rating systems for how energy-efficient a given home is: The US Environmental Protection Agency’s Energy Star for Homes (the most popular) and the US Green Building Council’s LEED for Homes.

Both require much greater energy efficiency than traditional American building methods even come close to offering–and for that alone they are invaluable. But an organization called the Passive House Institute US (PHIUS), featured in a recent New York Times article and based in Urbana, Illinois, is setting a new, much higher bar for energy conservation: By making a home’s envelope close to completely airtight, making the most of the sun’s natural heat by way of big windows facing south and using a combination of Institute-mandated building techniques and green products to keep that heat in the house when it’s wanted (and let it out when it isn’t), a house that passes the Institute’s certification process uses on average 75 to 95 percent less energy than most new buildings built in the US!

Building a home to the Institute’s standards is somewhat more expensive than traditional building, though the extra expense is often more than offset by the savings from lower energy bills. But because most low-income people can’t afford to spend an extra cent more than necessary on building, but stand to benefit from green housing as much as anyone else, Habitat for Humanity has begun to experiment with Passive Solar housing itself.

H4H Vermont’s Green Valley chapter is currently building the first Passive Solar house in New England, on a city-donated plot in the colonial village of Charlotte. And the house is not only PHIUS-certified, but pre-fab, too–it’s made of modular units that are made in a factory and then trucked in and assembled in near-complete condition. This way of building saves vast amounts of construction waste and goes a long way to protect the natural environment of the building site. The house will be the first pre-fab, modular Passive Solar house in the country, and hopefully will kick off a long-lasting trend in this kind of homebuilding.

The project is in collaboration with the nonprofit Vermont Energy Investment Corporation, builder Preferred Building Systems, Charlotte-based passive-house specialist Peter Schneider, and Boston-based architect JB Clancy.  The house was completed this month, and a family of four is expected to move in by Christmas.