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.

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.

New York City and other metropolitan areas have been hit by what some people are calling an epidemic – an epidemic of of bed bugs.  While long considered eradicated through the use of DDT in the 1950s (the toxic effects of which proved devastating to birdlife, as detailed by Rachel Carson in Silent Spring), bedbugs have seen a major resurgence in population in the last decade.

The bed bug – Cimex lectularius – is a tiny nocturnal insect about the size of an apple seed.  They sleep in the crevices of one’s bedding during the day and emerge at night to feast on the blood of humans, piercing the skin with two hollow feeding tubes.  One of these tubes injects its anticoagulating and anesthetic saliva, and the other extracts blood from the host for about five minutes.

No one wants to be infested with bed bugs – their bites leave large, itchy red welts over the body.  They’re notoriously difficult to get rid off, too – their eggs are microscopic and can fill very tiny corners of beds, blankets, carpets, nightstands, and chairs.  Anyplace where there is a crack or crevice is a potential living space for bedbugs, and they can survive for up to two months without feeding again.  Bedbugs have even been known to live behind peeling paint chips.  In other words, they are notoriously tenacious critters.

Bedbugs have captured the popular imagination, and for good reason.  There have been confirmed infestations of bedbugs in both the Brooklyn and NYC District Attorney offices; movie theatres and hotels in midtown pose challenges to local tourism; triage rooms in hospitals have had to shutter their doors.  There have been major infestations reported in every neighborhood and in every borough and populations seem to be spreading rapidly – in other words, there isn’t any place one can go to escape the threat of bedbugs.  Even the swankiest penthouse apartment is at risk of an infestation.

Controlling these insects is difficult, but it behooves any person who doesn’t want to be fed upon by the noctural insect to attack them as soon as an infestation is suspected.  Early infestations can be controlled through the use of targeted killings.  Larger and later infestations have to be handled by professional exterminators, some of whom use bedbug-sniffing dogs to discover where nests are located.  These inspections and exterminations can run in the thousands of dollars, and typically all bedding – including mattresses, blankets, and pillows – have to be thrown away.  Every article of clothing has to be washed in hot water – a laundry bill that could easily run into the hundreds of dollars.

So it is truly incumbent upon the person who suspects an infestation to attack the infestation early.

However, anyone concerned with the environmental and health consequences of cleaners or pest control products would surely want to avoid using anything particularly toxic or poisonous.  It’s not especially surprising that most bedbug killers are highly, highly toxic.  To spray toxin upon the mattress, nightstand, or anyplace near where one sleeps seems dangerous – especially when there are pets or children living in the household.

Several green products do exist, though, to address this issue.  Two of the green products that Green Depot carries are Rest Easy and K4 EcoBugFree for Bed Bugs.

Rest Easy

Rest Easy is an entirely natural product, which both repels and kills bed bugs.  Active ingredients include cinnamon, lemongrass, cloves, and mint and is also effective for killing fleas and dust mites, the latter of which is a common allergen.  Folks suffering from bed bugs or allergies could potentially benefit from this product.  Additionally exciting for anyone planning to travel – since bed bugs have been reported in numerous hotels throughout New York City alone – is the fact that this green product comes in a 2 oz. travel size – ensuring that no one picks up an infestation of bed bugs while away from home.


EcoBugFree is another option.  It is an environmentally-sensitive, minimal risk pesticide that qualifies for EPA Exempt status.  It has been designed to keep pets, children, and employees safe from toxins, poisons, and pesticide residues that are potentially harmful to one’s health.  In particular, this product eliminates the eggs of the bed bug – ensuring that the next generation nestled between the sheets never matures.  A bane for the bed bug, and a boon for the bedroom!

If you’ve been in the market for paint lately, you’re surely seen and heard the marketing noise about low- and zero-VOC paints. You know it’s something green, and clearly VOCs are something bad, so you’re intrigued and may even have bought some of this paint by now…. But you may also be wondering: What, exactly, are VOCs?

Well, as it turns out, there is no single definition of a VOC that is agreed upon by regulating agencies worldwide. But the letters stand for Volatile Organic Compounds, which the EPA used to refer to as  reactive organic gasses (ROGs), if that’s any help. Some occur in nature; others are man-made.

In the world of green products, VOC usually refers to a man-made, liquid solvent that gives off toxic fumes. You can often smell the VOCs in paint and other liquids you find in hardware stores–it’s that not-so-nice, often headache-inducing smell you get from wet paint, turpentine, varnish, and products in that vein. But a substance can continue to emit VOCs even after it has dried and you no longer smell anything, often for years at a time.

This is why VOCs are such a big deal when it comes to paint. According to the EPA,  indoor air pollution is one of the top 5 hazards to human heath–and VOCs are a major contributor to it. The EPA recommends the use of low- and zero-VOC paints, and it defines low-VOC as having 250 grams or fewer VOCs per liter. GreenSeal has an even lower limit of 50 grams for low-VOC paints.

Things become tricky, however, when color is added to a base: The VOC rating applies only to the base color, not whatever pigments might be added. So be sure to find out whether your tints are low-VOC, as well.

Then there’s zero-VOC, which is of course the best option. Most zero-VOC paints actually do have very low levels of VOCs, as the EPA requires only that they have less than 5 grams per liter to carry that label. But truly zero-VOC paints do exist–to find them, you simply have to know what you’re looking for on the label.

To start you out in the right direction, Green Depot’s house line of paints and primers, Ivy Coatings, is truly zero-VOC, even when tinted. And it’s available in a huge range of colors, including a set of four subtly different premixed shades of white–for just the right white, which can be more important than many people realize.

Green Depot also carries a number of other low- and zero-VOC coating options, including non-toxic Ana Sova Food Paint (which really is made of mostly food-grade ingredients, including milk proteins), Yolo Colorhouse paints, and a range of not only paints but wood stains, polyurethanes, concrete stains and more from AMF and EcoProCote.

Yellow paint photo credit: Even Roberts/

So you’re renovating, or maybe even building something new, and you’ve finally finished framing out your new walls. Now you’re ready to put up your drywall and maybe some tile, or maybe even wallpaper—but what about the ceiling? Sure, you can just drywall it too (and hopefully you’ve been using recycled-content drywall), but there are several other options to consider as well.

The decision of how to make your ceiling can be influenced by a number of factors beyond your decorative choices. A few things to keep in mind are how much sound transmission in and out of the room you want to allow, whether water and/or humidity will be present, whether the room’s activities require any particular kind of acoustics, and whether you’ll be applying tiles.

Here are a number of green products designed for ceiling use that you may want to consider, and some ideas on how they might best be used in your building project.

1) Recycled Content Drywall
If you’re not already using drywall with recycled content for your walls, your ceiling may offer another opportunity to include it. Typical drywall is made of a core of mined gypsum and two outer layers of non-recycled paper. The mining of gypsum typically launches large amounts of particulate matter into the air, threatening both the respiratory health of the miners and the air quality of the surrounding areas. And like most mining, the extraction process leaves large scars on the landscape at the mining site, and often contributes to soil erosion on the slopes where it is mined.

Instead of mined gypsum, recycled-content drywall is made of synthetic gypsum—a byproduct of the process coal-fired power plants use to limit the amount of acid-rain-causing emissions they release into the air. And not only does the use of synthetic gypsum reduce manufacturing waste, but it’s purer than mined gypsum, making for drywall that’s stronger and easier to work with. As an added benefit, the paper facing used on recycled content drywall is 100% recycled.

2) Tectum Interior Ceiling Panels
A dropped ceiling of rectangular panels, typically made of sound-absorbing (acoustical) materials, is another option. A dropped ceiling consists of a grid of lightweight metal strips that are hung from either exposed beams or a drywall ceiling, which hold the panels in place without screws or adhesive. This allows for easy access to any wiring or ductwork underneath, as well as easy replacement of any panel that needs it. Acoustical panels reduce the amount of noise bouncing around within the room, while also limiting the amount of sound traveling through the ceiling to rooms above.

For a green option, Tectum interior ceiling panels are made of wood fibers that are bound together without chemicals and come from Aspen trees grown in FSC-certified forests. The air-drying, low-energy binding process uses only sand, limestone, salt, magnesium oxide (from seawater), and water that gets recycled after use. The finished panels don’t off-gas at all, and are non-toxic enough to be added to compost piles for soil amendment. So not only do you get a quieter room, for a healthier indoor environment, but you get it without hurting the outdoor environment either! And for even further reduction in the noise coming out of the room , take a look at QuietRock Soundproofing Drywall.

3) Durock Cement Backerboard
If the room you’re building is a bathroom or kitchen, or any other room where high humidity and spilled water are common occurrences, you’ll need to use backerboard –commonly called “blue board,” because a common brand is (you guessed it) blue. Backerboard is typically used underneath tiles even in dry areas, where it acts as a surface stiff enough to keep the surface from flexing and pushing them off—and in wet areas, it provides a layer of water-blocking protection for the framing and surrounding rooms.

Durock cement backerboard is not only resistant to moisture, but mold as well, protecting the room’s air quality. And concrete is so durable that it’ll be a long time before you have to replace it, which saves the waste of valuable resources. And it’s even made of recycled materials—it’s 10-20% recycled fly ash.

Installing a new wood floor? Instead of traditional hardwood, you may want to consider an eco-friendly alternative: bamboo. It may be hard to imagine that reedy green plant growing wild in your yard making a good flooring material, but some varieties of bamboo (when mature and properly dried) are as hard as oak–and some are even harder.

Photo: chefranden at

Green Depot carries bamboo flooring by Foundations, a New York state-based company that offers click-together “floating” strand boards, as well as traditional tongue-and-groove solid-strip options, both in prefinished and unfinished varieties. Foundation’s strand planks are made of the Moso variety of bamboo, which proves to be two times harder than red oak when subjected to the industry-standard Janka ball test. And Moso isn’t a natural food supply for a pandas, so harvesting it even in the wild doesn’t endanger their habitat.

But why else is bamboo such a good choice? The reasons are many, beginning with bamboo’s rapid renewability, which makes it one of the greenest of green products used in building. A tree takes 80 to 120 years to grow to a size where it can be harvested for hardwood flooring planks, but a bamboo plant reaches maturity in only 3 to 6 years with minimal (if any) fertilization or pesticides, and it renews itself without replanting. This means it requires not only fewer natural resources to thrive, but less labor, as well. And bamboo can easily grow up to a foot a day, so it’s not just fast, but plentiful.

Photo: Ajari at

Bamboo is also a boon to the natural environment itself, in a number of ways. Mature bamboo has a very complex and dense root structure (which, incidentally, is why is can be so hard to get out of your garden), which goes a long way to avoid soil erosion in areas where it’s planted. Furthermore, a bamboo forest absorbs up to twice as much carbon dioxide as trees.

From a social responsibility perspective, as well, bamboo is winner—600 million people worldwide depend on income from it, and the industry employs nearly 6 million people in China alone. And as it grows in popularity, those numbers only expand.

Then there’s affordability, which ties back to bamboo’s ability to renew itself rapidly. The laws of supply and demand are at work here: A product that springs back into place quickly and with so little effort and expense can easily be kept in abundant supply, so prices for it can be lower, even in times of great demand. And its durability gives it another layer of affordability, as many kinds of bamboo flooring can go for long periods without refinishing or replacement. Several brands, including Foundations, coat their pre-finished planks with multiple layers of a water-based, zero-VOC, aluminum oxide-infused polyurethane that doesn’t off-gas at all. Nice!

And that’s not even touching on the design options bamboo flooring offers. Bamboo is available in any number of colors, many of which can be achieved using eco-friendly methods. Heating bamboo makes it darken to a rich amber color without the use of stain, and bleaching it in non-toxic hydrogen peroxide gives it a birchlike white-blond color. Its natural tone is a warm golden hue that lies somewhere in between the two, and bamboo can be colored with traditional wood stains to take it to anywhere from a medium chestnut brown to a near-black ebony.

Bamboo’s narrow-strand structure allows it to be pressed into planks in a number of different formats, unlike wood, which of course comes naturally bound into wide pieces (tree trunks). Some bamboo flooring manufacturers even offer planks made of mixed dark- and light-colored strands, for an unusual streaky look. Still others turn the plant’s fibers the short way, so the cut ends of the stalks are what make up the visible surface. The effect is a sort of small-dot pattern that is unique to bamboo.

As a side note, Green Depot also carries Plybam, an excellent companion to bamboo flooring. Plybam is plywood made entirely of bamboo instead of wood veneer, and it’s perfect for use in cabinetry, furniture, paneling or any other project that usually calls for plywood. Its edges have a multidirectional pattern that offers an alternative to plywood’s striped edges, and is attractive enough to make edge veneers a thing of the past.