Ask the Green Architect: Environmental Carpeting; How 'Green' Saves Money; Rules of Thumb

Ask the Green Architect: Environmental Carpeting; How 'Green' Saves Money; Rules of Thumb

  • Green carpeting
  • How "green" saves money
  • Rules of thumb for selecting green systems in buildings

    I saw your recent article in the September 2006 issue of Dwell on "Flooring with a Conscience." However, it only addressed wood flooring options. What environmental suggestions do you have for carpeting?

    Eric: Carpeting is the ubiquitous floor covering in America, desired as much for its texture, as for its ability to cover a variety of hidden sins underneath. Combine that with their low cost per square foot and you have carpet as the most selected floor covering in the country, covering 70% of our floors. In 1993, nearly 1.5 billion square yards of carpeting was sold, enough to cover nearly 40% of Rhode Island.

    Once considered the status symbol of a luxurious home, carpet is now attributed with a long list of related indoor air quality problems and material waste issues.

    Health Concerns
    In the 1990's, after receiving hundreds of complaints (over 500 to be exact) about carpet-related health effects, the U.S. Consumer Product Safety Commission (CPSC) commissioned a study examining carpet chemical emissions. The landmark study (found here: identified dozens of chemicals released from carpets, only 31 of which were identified.
    The most prevalent chemicals styrene and 4-PC, both of which from the latex backing used on most carpeting. Styrene is a known toxin and suspected carcinogen. Although 4-PC has not been shown to be toxic, it creates an odor so distinctive, it is the most responsible for that "new carpet smell."

    The Problem with Carpet
    Carpet, especially wall-to-wall carpet, has several inherent environmental issues.
  1. Carpet is typically made from synthetic, oil-based materials. These are considered toxic and off-gas harmful chemicals.
  2. Carpet is typically backed with vinyl (PVC) and vinyl is harmful at every stage of its lifecycle.
  3. The synthetic and mixed materials make carpet (nearly) impossible to recycle.
  4. Carpet requires a great deal of energy to maintain, since it must be vacuumed.
  5. Vacuuming alone does not clean carpet and instead creates an environment for pests, mold and mildew to reside. Carpet is host to numerous indoor-air quality issues, including the spread of asthma.

How to Correct It
Luckily, a select group of carpet manufacturers have addressed some or all of these issues. Some of these initiatives include such wonderful ideas as:
  1. Carpet made from natural, renewable fibers and materials.
  2. Carpet backed with natural, healthy materials.
  3. These companies have accepted their responsibility for their products and offer "take-back" programs, where they accept the carpet at the end of it's use and recycle it back into their supply chain.
  4. The use of carpet tile is an environmentally preferable alternative to wall-to-wall since damaged tiles can be individually replaced without having to replace an entire floor.
  5. Used sparingly at entranceways, carpet can be used to control pollutants being tracked into a building.

Padding or Glue-Down?
Natural padding is preferred over glue down applications for several reasons: the adhesives typically contain volatile organic compounds (VOC's) which off-gas harmful chemicals; the adhesives make replacing or removing the carpet much more difficult; the adhesives can make the carpet unrecyclable.

Carpeting Pioneer
In 1973, an industrial engineer named Ray Anderson founded Interface, a carpet manufacturing company.

Over the next two decades, Anderson steered the company towards profitability, achieving the kind of success most business people envy. Oddly enough, it was Anderson himself who grew uneasy about his success. A friend suggested he read Paul Hawken's, The Ecology of Commerce and it changed the course of both his life and his company.

It became instantly clear to Anderson the processes of nature must be incorporated into every aspect of his product. He chronicles this catharsis in his wonderful book, Mid-Course Correction.

Today, Interface offers some of the most advanced sustainable carpeting available. For example, their Flor carpet tile is made from recycled or renewable resources, using their pioneering low-waste manufacturing process. Not only is Flor a green carpet, it also comes in an attractive variety of patterns designed to be arranged in an infinite number of ways.

Suggested Carpet Manufacturers

Shaw Contract Group
Phone: 877-502-7429 / 800--257-7429

Toll-free: 800-336-0225

Milliken Carpet
Toll-free: 800.241.4826

Bentley Prince Street
Toll-free: 800-423-4709

Mohawk Industries, Inc.
Phone: 800-622-6227

J&J / Invision
Toll-free: 800-241-4586

Carpet Padding

Ethos Carpet-Cushion Backing
C&A Floorcoverings
Toll-free: 800-248-2878

Carpet Padding
Earth Weave Carpet Mills, Inc.
Phone: 706-278-8200

EcoSoft Carpet Cushion
Invista Commercial Flooring
Toll-free: 800-438-7668

Hartex, PL and DublBac Series Carpet Cushion
Leggett & Platt, Inc. - Fairmont Division
Phone: 770-459-7060
Toll-free: 877-579-4737

Further Reading

Carpeting, Indoor Air Quality, and the Environment

IAQ Publications - Indoor Air Pollution

Carpet and Rug Institute Green Label IAQ Program

Choose Green Report: Carpet

Environmentally Responsible Carpet Choices

The Inside Story: A Guide to Indoor Air Quality

Green Cleaning for Carpet Cleaners

Story Sources

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What are some examples of how building green can actually save you money?

Since green building is really about finding opportunities to conserve our resources, the long-term benefits are quite impressive.

Here is a complied list of talking points so you can discuss and debate these benefits with those skeptics. The sources have been included to remove any question of their accuracy.

I welcome your additions to this list.

An upfront investment of 2% in green building design, on average, results in life cycle savings of 20% of the total construction costs - more than ten times the initial investment
Source: The Costs and Financial Benefits of Green Buildings: A Report to California's Sustainable Building Task Force, October 2003

A $4 investment (per square foot) in building green nets a $58 benefit (per sq. ft.) over 20 years:

  • Estimated health & productivity benefits: $46
  • Operations & maintenance: $8.50
  • Energy savings: $5.80
  • Emissions savings: $1.20
  • Water savings: $0.50
    Source: U.S. Environmental Protection Agency

    Tenants can save about 50 cents per square foot each year through strategies that cut energy use by 30%. This can represent a savings of $50,000 or more in a five-year lease on 20,000 square feet
    Source: U.S. Environmental Protection Agency

    Green building occupants are more productive
    Average annualized costs for personnel amount to $200 per square foot, compared to $20 for bricks and mortar costs and $2 for energy costs.
    Source: eBIDS

    LEED Certified case studies show examples of 2% to 16% increase in productivity.
    Source: eBIDS

    A study by Carnegie Mellon University measuring the relationship between increased lighting control and productivity showed an average increase of 7.1% in productivity.
    Source: eBIDS

    Sales in stores with skylights were up to 40% higher compared to similar stores without skylights
    Source: California Board for Energy Efficiency Third Party Program

    Students with the most daylighting in their classrooms progressed 20% faster on math tests and 26% faster on reading tests in one year than those with the least day lighting.
    Source: Heschong Mahone Group study, "Daylighting in Schools," conducted on behalf of the CA Board for Energy Efficiency

    An average non-skylit store would have 40% higher sales, with the addition of daylighting. The study looked at 108 stores operated by a chain retailer - 2/3 had skylights and 1/3 were electrical lighting, mostly fluorescent.
    Source: Heschong Mahone Group study

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What are some rules of thumb for selecting green systems in buildings?

By definition, a rule of thumb is "a principle with broad application that is not intended to be strictly accurate or reliable for every situation." (Source:

That being said, please do not take "rules" as rules. They are provided for initial budgeting and estimation.

The following list of guidelines was developed after over a decade of work in green building. As always, I welcome your additions to this list.

Radiant Heating
  • A radiant heating system will cost about $1.50 - $1.75/sq ft, not including the heat source.

    Green Roofs
  • A fully integrated green roof system will cost between $12.00-$24.00 per square foot

  • A green roof tray system will cost around $8-10 per square foot

  • A moss roof can be done for as little as .25 cents per square foot

  • A green roof must be considered to weigh the same as water, about 60 pounds per cubic foot, so plan the structural and drainage accordingly

  • For every 100 square feet, integrated solar panels produce between 1 to 1-1.5 kW. So a 5 kW system would require about 500 square feet.
    This varies based on geography and solar orientation.

  • As a rule of thumb, take your total annual kilowatt hours (kWh) from the utility bills and divide that number by 1930. This will give you the approximate size of your system in kilowatts.

  • Each kilowatt will cost between $5000-9000 installed (before rebates). Cost and available rebates vary by region.

  • For every 100 square feet of solar panels, budget $5000 - 7500.

  • Electricity Cost ($/kWh) 0.10 cents / kW (Confirm with your local utility)

    Water Catchment
  • Just an inch of rainfall on a 1000 square foot roof will produce 632 gallons of water.

  • San Francisco averages 20.4 inches of rainfall per year, potentially saving nearly 13,000 gallons of water from a typical roof. (San Francisco has an average annual rainfall of 20.4 inches per year -- 20.4" = 1.7 feet.)

  • ___ square feet of roof x ___ feet of rain = ___ cubic feet of water saved in a year

    Passive Solar
  • The building should be elongated on an east-west axis.

  • The building's south face should receive sunlight between the hours of 9:00 A.M. and 3:00 P.M. (sun time) during the heating season.

  • Interior spaces requiring the most light and heating and cooling should be along the south face of the building. Less used spaces should be located on the north.

  • An open floor plan optimizes passive system operation.

  • Use shading to prevent summer sun entering the interior.

  • The Center for Renewable Energy and Sustainable Technology (CREST) has an online lesson on calculation of Sun Angles and overhang calculations.

  • As a general rule, the depth of a room should not exceed 2 to 2.5 times the height of the window. Be sure to include any overhangs in that depth.

    Thermal Mass
  • Two primary elements of passive solar heating are required:
    * South facing glass
    * Thermal mass to absorb, store, and distribute heat

    • Do not cover thermal mass floors with wall to wall carpeting; keep as bare as functionally and aesthetically possible.

    • For every square foot of south glass, use 150 pounds of masonry or 4 gallons of water for thermal mass.

    • The surface area of mass exposed to direct sunlight should be 9 times the area of the glazing.

      Waterless Urinals:
      1.0 gallon/flush x ___ flushes/day x 365 days/year = ___ gallons saved x $___/gallon = $_____

      Dual Flush Toilets:
      Save .6 gallons/flush x ___ flushes/day x 365 days/year = ___ gallons saved x $___/gallon = $___

      Water Use
      Typical Residential Water Use:
      • Showers and Baths - (20%)
      • Potable Uses - (9%)
      • Clothes and dishwashing - (16%)
      • Toilets - (19%)
      • Lawns and gardens - (36%)

      • Total: 100 gallons per day in water demand

      • Toilets: 1.6 gallons per flush
      • Showers: 2.5 gallons per minute
      • Washing Machine: 35 gal. per load
      • Dishwasher: 8.5 gal. per load
      • Toilet: 4.0 flushes per person per day
      • Shower: 4.8 minutes per person per day

      • Flyash concrete is the same price as ordinary concrete without flyash.

        Eric Corey Freed is principal of organicARCHITECT and teaches Sustainable Design at the Academy of Art University in San Francisco and University of California Berkeley. He is on the boards of Architects, Designers & Planners for Social Responsibility (ADPSR), Green Home Guide and West Coast Green. This article has been excerpted from his upcoming book, The Inevitable Architect: A Phase by Phase Guide to Green Building.