Glossary and Green Approaches

//Glossary and Green Approaches
Glossary and Green Approaches 2017-06-20T09:48:50+00:00

Glossary of Useful Green Building and Building Science Related Terms

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


A

Active System

In a home, an active system is one that requires mechanical energy to work. Heaters and air conditioners are part of an active HVAC system. The opposite of an active system is a passive system.

Alternative Energy

Alternative energy consists of those sources which are newer and less often used than conventional energy sources like coal and nuclear power.

Examples of alternative energy sources are wind, solar, and geothermal. These alternative energy sources are also examples of clean energy sources.

Building or retrofitting a home to use solar energy for hot water and/or to produce electric power,  when combined with strategies to conserve energy, can drastically reduce a home’s ongoing utility bills.


B

Building Code

A building code is a set of minimum standards for building requirements, often pertaining to structural and fire safety. Building codes are generally set at the state level. Building codes help ensure that all construction meets an agreed-upon minimum standard of safety and comfort.

The term “building code” as it is commonly used rarely, if ever, pertains to green building issues nor to standards higher than minimum required.

Building Science

Building science is the term applied to facts and theories of science pertaining to the construction and performance of buildings. It is important to have a clear understand of building science in order to build high-performance, green, LEED-rated, Passive House-certified, sustainable homes.

BTU

BTU is an acronym for “British Thermal Unit”. It refers specifically to the amount of energy needed to change the temperature of a pound of water by one degree Fahrenheit. This is the measure of power for many areas pertaining to home energy, including power, heating, and air conditioning.


C

Clean Energy

Clean Energy is the term for sources of energy that do not emit pollution in order to produce that energy. Geothermal, solar, hydro, and wind are all clean energy sources.

Carbon Footprint

According to the EPA, “many of our daily activities – such as using electricity, using hot water, heating and cooling a home, driving a car, or disposing of waste – cause greenhouse gas emissions.”  The total of these emissions for an individual, household, organization, or company is known as its carbon footprint.

Conventional Home

A conventional home is one that is built to meet Building Code standards. It meets minimum requirements for safety and comfort.  A green, high-performance home, such as a Net Zero or Zero Energy Ready home, is one that meets much higher performance standards.


D


E

Energy Star

Energy Star is an energy efficiency rating administered by the EPA. Appliances, devices, and even homes can be Energy-Star rated. Given its high and strict standards, the Energy Star rating is an easy way for builders and homeowners to see that a building material is highly energy efficient.

Energy Star appliances are a part of many high-performance homes and are required in Zero Energy Ready homes.

Environmental Protection Agency (EPA)

The Environmental Protection Agency, or EPA, is an office designated by the government dedicated to protecting “human health and the environment.” The EPA administers such initiatives as the Energy Star program.


F

Fossil Fuel

The term “fossil fuel” refers generally to oil, coal, and gas. They  get this name because they are the remains of living organisms, which have been converted to fuel over millions of years by the natural forces of heat and pressure. When you use a fossil fuel, one of the waste products is carbon dioxide which contributes to your carbon footprint.

Fossil fuels are the opposite of clean energy; using them causes pollution. Fossil fuels are generally used in conventional homes, but not (or to a much smaller degree) in high-performance homes.

Fossil fuels are also volatile in price and can cause both high energy bills and high fluctuations from month-to-month and year-to-year, depending on supply. The best ways to minimize the impact of these costs are to use various strategies to conserve energy and to use alternative energy sources instead.

Envelope

The envelope of a building refers to those elements that divide the indoors from the outdoors: the foundation, exterior walls, exterior windows and doors, attic floor and/or roof. It is important to construct an envelope well and tightly to ensure the indoor comfort of a home.

Framing

Framing is the structural support of a building. It can be compared to skeletons in living beings. In homes, framing is generally made of lumber. Framing makes up part of a home’s envelope as well as its interior partitions.

Green homes are framed differently than conventional homes.  There are many options for framing a green home.


G

Geothermal

Geothermal is literally “earth heat”, or heat derived from the earth.  It is a passive, renewable, clean energy source.

Geothermal for homes generally refers to systems that start with a heat exchanger in or very near a home. The heat exchanger is connected to pipes which route a heat transfer fluid into one or more wells, where the ground temperature is consistently 50-55 degrees. That fluid is pumped down the pipes and returned to the heat exchanger, which extracts and concentrates the heat energy, which is then delivered to the home’s heating and cooling system. In the winter, the earth is warmer than the air, helping to heat homes; in the summer, the heat from the home is deposited in the cool earth, helping to cool homes.

In areas that BPC builds homes, a geothermal system’s energy efficiency is high, but the cost efficiency is usually lower than that of air-source heat pumps, which BPC installs in homes more often than any other.

Grey Water

Grey Water is a household’s waste water (with the exception of toilets, which is referred to as “Black Water”). It is the waste water from kitchen and bathroom sinks, tubs, and shower drains. It includes waste water from appliances like clothes washers and dishwashers.

Grey Water can be collected, filtered and reused (for example, in landscape irrigation), which can reduce a home’s overall water usage.

Grey Water System

A Grey Water System captures a household’s grey water, often via a drum or barrel, which is then piped or drained into a home’s landscaping. It is important to check local building codes to make sure that a grey water system is permitted.

Green Building

Green building is both a noun and a verb.

As a noun, it refers to buildings that have been built to use energy, water, and materials resources responsibly. As a verb, it refers to labor and materials that are responsibly-sourced and resource-efficient.

Green building strategies can be used in a new building or building renovation and are applicable to all phases of the life of a building: development and siting, design and construction, operation and maintenance, and remodeling/renovation to eventual demolition.

When a building is described as “green”, it is helpful to understand what the developer, designer, and/or builder mean, as this term can vary widely from region to region and even profession to profession.

Green Building Standard

Green building standards are objective, generally quantitative, rating systems by which the “greenness” of a building can be commonly understood.

Examples of green building standards include HERS, LEED, Passive House, and the Living Building Challenge. The different standards emphasize different areas such as materials sourcing and operating efficiency.

These ratings can positively affect a home’s assessment when obtaining third-party financing for building and remodeling; they also set the foundation for a more accurate, consistent understanding between realtors, buyers, and sellers about the high-performance elements of a sustainable home.

Green

“Green” is a widely-used term that can mean a wide variety of things to different people. Generally, it refers to systems, processes, and materials that are environmentally and ecologically sensitive; that work with the Earth, protect it or improve it.  “Sustainable” is often used as a synonym for “green”.


H

HERS

HERS is an acronym which stands for “Home Energy Rating System”. It is a building certification that gives designers, builders, and building users a consistent standard by which to measure a home’s energy efficiency. HERS is administered by RESNET, the Residential Energy Services Network.

Check out the HERS scores of homes BPC Green Builders has built and remodeled.

High Performance Home

A high performance home is typically defined as one which is significantly more energy efficient than conventional homes.

High performance is measured using standard ratings systems like HERS and is achieved through thoughtfully combining an air-tight, well insulated, thermal envelope; a highly efficient heating and cooling system; ventilation and air filtration for high indoor air quality; and clean energy sources, such as solar photovoltaic electricity.


I

Insulation

Insulation is any material used in a building to minimize the energy required to maintain comfortable indoor temperatures relative to outside temperatures. Insulation is the best way to reduce heating and cooling costs while maximizing indoor comfort. There are many different types of insulation; some of the most common are fiberglass and mineral wool batts, foam boards, spray foam, and cellulose.

In addition to minimizing energy use, insulation can also be used as a moisture barrier and soundproofing.

Insulation’s effectiveness is measured in “R values”, a number that describes how resistant the material is to heat flowing through it. Higher R values are always better. However, the cost to install varies greatly, depending upon whether the location is a foundation slab or wall; a framed floor, wall, or roof; or window.  Therefore, different types and amounts of insulation are typically installed in these different areas.

Insulation is generally used exclusively as part of a home’s thermal envelope, except for soundproofing which can be placed in interior walls and partitions.


J


K


L

LEED

LEED stands for “Leadership in Energy & Environmental Design”.  It is a building certification that gives designers, builders, and building users a consistent standard by which to measure the sustainability of a building’s construction and operation.

LEED is administered by the USGBC, the United States Green Building Council. As of this writing, there are 5 different types of LEED certifications:

  1. LEED for Homes
  2. Building Design + Construction
  3. Interior Design + Construction
  4. Building Operations + Maintenance
  5. Neighborhood Development

LEED for Homes

LEED for Homes is a building certification program that confirms the level of sustainability of a home’s construction. It involves four main steps: registering the project; verifying the milestones; reviewing it with a certified rater; and certification.

There are 4 levels of LEED for Homes certification. They are measured by points with a maximum allowable number of 130. The certification levels are:

  1. LEED for Homes Certified (40-49 points)
  2. LEED for Homes Silver (50-59 points)
  3. LEED for Homes Gold (60-79 points)
  4. LEED for Homes Platinum (80+ points)

The number of points required varies by home, according to the number of bedrooms relative to the size of the home.


M

Moisture Barrier

In building homes, it is vital to keep all unwanted water (including excessive water vapor) from getting into the floors, walls, or roof   of the house. Other terms commonly used are “waterproofing” and “vapor barrier.”  Asphalt-coated kraft paper, plastic sheeting, various membranes, specialty paints, and foam boards are common moisture barriers.

The moisture barrier is installed in multiple exterior locations (under the slab, on foundation walls, framed walls, and roof) to control and divert rain, dew, humidity, etc., as well as to resist  vapor diffusion to the interior. It is vital that the barrier is continuous, or else water or vapor will have an opportunity to get inside where it can lead to mold and cause building materials to rot and fail.

Vapor retarders are also important. In cold climates, they are installed to diminish the diffusion of interior-sourced moisture vapor into the exterior walls and roof.

If a rainwater catchment system is installed, some of this water can be used for landscape irrigation.


N

Net Zero Ready Home

Net Zero Ready Home is not an “official” term used within the Green Building industry but it is commonly used by homeowners for either a Net Zero home or a Zero Energy Ready Home or a home that is both.

Net Zero Home

A Net Zero Home is a home that produces at least as much energy as it consumes. “Technically” such a home does not need to be energy efficient but typically it is, so that less energy need be produced to offset the energy used.


O

OC (On Center)

The distance between the center point of wood (usually 2×4) or other studs  used to frame a home. Conventional homes typically place studs ’16” OC’.  Green building sometimes places larger wooden stud (usually 2×6) ’24” OC’. This increases the space for insulation and the amount of wall backed by insulation. It also reduces the number of points in an outside wall where heat can be transferred through studs provide a lower amount of insulation value.


P

Passive House

A Passive House (PH) is a home that requires very little energy for heating and cooling.

PH certification can be obtained through PHIUS, the Passive House Institute of the United States (PHIUS). There is a separate and somewhat different PH certification offered in the US by the international Passive House Institute (PHI).

To meet PHIUS PH standards, as some of BPC’s homes do, a home must meet the climate-adjusted and cost-optimized energy-use requirements of the program.

Passivhaus

The German term for passive house and the term used in Europe. Passivhaus standards are higher than some Passive House standards in the United States. PHIUS standards are more similar to Passivhaus than other domestic Passive House standards.

Passive System

In a home, a passive system is one that requires no mechanical energy in order to function. Heating a house with heat from the sun that enters through the windows and is stored in a thermal mass, such as concrete, water, or any heavy building material, is the most important passive system. BPC Passive House homes get about half of the energy needed to heat them from the sun directly.

Natural air circulation and daylighting are other examples of passive systems. The opposite of a passive system is an active system.

PV (Photovoltaic)

See Solar Photovoltaic


Q


R

R-Value

R-Value is the measure of a material’s ability to resist heat flowing through it. The higher the R-Value, the more insulating a material is. In residential building, R-Values are most often used to describe insulation.

Renewable

Renewable energy comes from sources which are essentially undiminished when used, or naturally replenished within a human timeframe (years or generations, rather than millions of years): wind, solar, hydro and geothermal are all examples of renewable energy. Fossil fuels (coal, oil, gas) are not renewable.

Renewable can also refer to building materials. Bamboo and pine for example can be grown, harvested and regrown in relatively short periods of time. They are “farmed” sources of wood. Certain types of wood (old growth type trees) take much longer to grow and harvesting can result in it becoming extinct as a species.

Renewable Energy

Renewable energy comes from sources which are essentially undiminished when used, or naturally replenished within a human timeframe (years or generations, rather than millions of years): wind, solar, hydro and geothermal are all examples of renewable energy. Fossil fuels (coal, oil, gas) are not renewable.

Renewable can also refer to building materials. Bamboo and pine for example can be grown, harvested and regrown in relatively short periods of time. They are “farmed” sources of wood. Certain types of wood (old growth type trees) take much longer to grow and harvesting can result in it becoming extinct as a species.

Resilient Home

A resilient home is one that has the capacity to maintain comfortable living conditions in the event of extreme situations: catastrophic weather, natural disasters, and extended utility service interruption.

Resilience can be understood in terms of energy production, water usage, and waste management.


S

SIP

SIP is an acronym that stands for “structural insulated panel.”  SIPs are a sort of building material sandwich: an insulating foam center between two structural boards, often made out of OSB (a plywood-type product made from wood scraps.

These panels are often highly energy efficient. They eliminate heat leakage through framing materials and are relatively easy to make air-tight. They can also reduce construction time compared to  framed wall construction. They are suitable for use in high performance homes.

Sustainable

In building, sustainable often refers to materials and processes that are resource-efficient. It can also refer to materials and processes that only used renewable resources. This means that they are environmentally responsible to build and cost-effective to operate.

Although definitions of sustainability can vary widely (see also “green”), a sustainable material or process is generally understood as one that exists in productive symbiosis with its environment.

Sustainable processes can also be understood as passive systems and renewable energy.

Solar Power

In building, sustainable often refers to materials and processes that are resource-efficient. It can also refer to materials and processes that only used renewable resources. This means that they are environmentally responsible to build and cost-effective to operate.

Although definitions of sustainability can vary widely (see also “green”), a sustainable material or process is generally understood as one that exists in productive symbiosis with its environment.

Sustainable processes can also be understood as passive systems and renewable energy.

Solar Photovoltaic

Solar photovoltaic panels (PVs) are often made out of silicon and convert sunlight into electrical current.

The efficiency of these panels has increased greatly since they were first manufactured 40+ years ago. The manufacturing costs have gone down dramatically as well. This has made electricity from photovoltaic panels close to, equal to, or lower than some other common sources of energy. Solar PVs are also non-polluting, an example of clean energy.

Sometimes, utility companies or national programs provide rebates for the installation of PV systems, as well as credits for excess power that is sent from the home’s panels to the power grid. This means, not only is this a clean energy source, it can also be used to recover the costs of the PV system, and in some cases even generate income for the homeowner.

Solar Thermal

Solar thermal is simply solar energy in the form of heat.

Solar thermal systems trap heat from the sun and heat or preheat water to heat the home or for hot water to be used in the home.

Solar thermal systems used on larger scales can be used to heat water, fluids, and other materials to very high temperatures which then can be used to generate steam and create electrical power.


T

Thermal Bridging

Many building materials are not good insulators (concrete, steel, wood) and act as paths for unwanted, high levels of heat flow, bypassing insulation and thereby wasting energy.  When such a material is not used carefully in the thermal envelope of a building, it creates a thermal bridge. BPC utilizes numerous new construction strategies to eliminate thermal bridges through the exterior floor, walls, and roof of a home.


U

U-Value

U-Value is the inverse of R-Value.  It is a measure of a material’s ability to resist heat flowing through it. The lower the U-Value, the more insulating a material is.  In residential building, U-Values are most often used to describe windows.


V


W

Wind Turbine

A wind turbine is generally a very tall, slender device that looks like a huge fan with skinny blades that converts wind into usable electricity. Wind turbines are one kind of passive or renewable energy.

Wind turbine technology only works in certain areas where wind of a certain speed is reliably found. Wind turbines can be installed on or near homes, in some locations, but are generally not as cost effective as other alternative energy options. Their greatest efficiency and power output comes at larger scales so they are usually built and maintained by utilities or other large companies.


X


Y


Z

Zero Energy Ready Home

This is a term (and certification program) used by the DOE (Department of Energy) that refers to newly constructed homes or whole house remodels that are so energy efficient that the energy required for space heating, hot water, and other household needs could be entirely satisfied by renewable energy sources.

Prior to being known as a Zero Energy Ready Home, the certification program was called DOE Challenge Homes.