Dictionary of Terms

Architecture 2030 – This is a set of goals to limit the effect that buildings have on the environment in regard to carbon emissions. Buildings are the source of almost half of all global greenhouse gas emissions. Without intervention, these emissions will increase 37% by 2030. This organization hoped to reduce carbon emissions by 50% by 2005, 60% in 2010, 70% in 2015, 80% in 2020, and 90% in 2025 by implementing sustainable design principles.

Certified wood products – Certified wood products are products made from lumber that is harvested in a sustainable manner and certified by a third party. Certification groups are: FSC (Forest Stewardship Council), SFI (Sustainable Forestry Initiative), and the CSA (Canadian Standards Association). These certified wood products all have the chain of custody certificate which tracks the lumber from the forest to the user. Trees are harvested from managed forests to reduce depletion of our natural resources.

Convective loops – A convective loop, whether inside a wall cavity or in another building assembly, occurs when air rises along a warm surface and falls along a cold surface, creating a circular movement of warm and cold air. A convective loop transfers heat through the building assembly, requiring more energy to replace the lost heat in a heating season and lost cool air in cooling seasons.

Cradle-to-cradle design – Cradle-to-cradle design means that the design process includes what a raw material may become after its initial useful life is over. The goal is not to de-engineer used materials, for example, to make a plastic composite deck material out of computer laptop cases mixed in with pop bottles etc., but to reuse materials at the level for which they were originally designed... indefinitely. Some of the best examples of this right now are some commercial carpets which can be remanufactured as carpet through infinite life cycles. Learn more here.

Diffusion – This refers to the movement of molecules through any material. The movement takes place as a result of thermal and concentration gradients in any given material.

Displacement ventilation – This refers to a method of letting cooler air replace warmer air in a space to promote natural ventilation. This method uses much less energy than traditional forced air. It also reduces circulation of indoor pollutants by bringing in fresh air to circulate.

Drainage plane – This refers to a waterproof layer including structural elements that are designed to drain water away from the building. This would include window flashings, house wrap, building paper, etc.

Grey water – Waste water can be divided into grey water and black water. Black water is sewage from toilets and other unsanitary sources. Grey water is waste from showers and clothes washing, etc. and can be safely reused with some treatment.

Grey water heat exchanger – This device transfers heat in your waste pipes, through a heat exchanger, to pre-heat or temper cold water before it enters your hot water heater.

Grey water recycling – This process takes waste water from showers, clothes washers, and other grey water sources into a holding tank, where it is filtered and used to flush toilets and other purposes.

HERS raters – HERS raters are special inspectors that are certified to rate homes according to the Home Energy Rating System (HERS). These ratings include field verification and diagnostic testing to determine energy efficiency levels among homes tested for duct efficiency, envelope leakage, and building insulation for compliance with current building efficiency standards.

Light pollution reduction – In most cities, it has become difficult to see the stars in the night sky. To reduce light pollution, people are encouraged to have lights that point downwards instead of up, or in all directions. It is also safer to have lower levels of contrast between light and dark areas. Going from a lit up area to a dark area, the eyes are forced to adjust. The older a person gets, the slower the eyes adjust to changing light. Increases in light at night also interfere with natural animal migration and the animal’s nocturnal activities.

Life cycle assessment – Life cycle assessment allows the manufacturer to determine the amount of energy and waste generation associated with the manufacturing of any product. Life Cycle assessment also takes into account the cost on the environment and the community. The categories that are dealt with are: water pollution, air pollution, global warming, environmental degradation, ozone depletion, habitat destruction, and human health.

Locally sourced materials – This concept puts emphasis on getting all or most of your building materials from a maximum 500 miles away from the site. This reduces the amount of carbon dioxide given off from transport of goods and services. It also helps the local economy.

Low VOC paints – VOCs are volatile organic compounds. These compounds are given off from things like paints, varnishes, etc. These compounds can be hazardous to your health.

Passive House (Passivhaus) – This is a super insulated house that cannot use more than 15kwh/m2 per year for space conditioning. This house uses advanced window technology, it is extremely air tight, has good ventilation, and it uses 85% less energy than Minnesota’s current standard. Learn more here.

Passive solar design – Passive solar refers to design techniques that utilize natural heating and cooling from the sun. Through design, you can passively heat a house or building and through shading, you can help keep a house or building cool. This idea helps to reduce the need for fossil fuels to heat or cool a house or building.

Permeable pavement – Permeable pavement is a pavement design that allows water to seep through the pavement directly into the ground. This reduces run off, erosion, and pollutants such as oil and grease running off into the sewers and then rivers and lakes.

Permeance – This refers to the ease at which water molecules can pass through any material. We generally think of plastic sheeting, but many materials have known vapor retarding qualities; insulating foam, plywood, and sheetrock to name a few. The current code has the following definitions:

Class I Vapor Retarder: 0.1 perm or less
Class II Vapor Retarder: 1.0 perm or less and greater than 0.1 perm
Class III Vapor Retarder: 10 perm or less and greater than 1.0 perm
The current proposals are to define them this way:
Vapor impermeable: 0.1 perm or less
Vapor semi-impermeable: 1.0 perm or less and greater than 0.1 perm
Vapor semi-permeable: 10 perms or less and greater than 1.0 perm
Vapor permeable: greater than 10 perms

Photovoltaic – Photovoltaic systems are systems that collect the sun’s energy and convert it into electricity.

Solar thermal systems – Solar thermal systems use the radiant energy of the sun to heat water or a heat transfer material for homes and buildings.

Thermal energy storage – Thermal energy storage refers to a process of storing up heat or cold for later use. One example would be storing up cold water or ice at night when energy costs are cheaper and then using that cold water or ice to cool the building during the day.

Triple bottom line – Triple bottom line refers to the practice of getting away from a business only thinking about the bottom line financially, to thinking about costs environmentally as well. The three categories this idea takes into account are: people, planet, and profits.

Zero-net-energy – This concept refers to buildings and communities that produce all of their own energy from onsite renewable sources or that purchase energy from those who produce it from renewable resources.