Von Löwen Designs

Active closed-loop solar water heater: Solar water heater in which an electric pump circulates a freeze-protected heat-transfer fluid through the collector and heat exchanger within a storage tank.

Active drainback solar water heater: Solar water heater in which water or another heat-transfer fluid is pumped through the collector and drains back to a tank in the house when the pump turns off.

Advanced framing: House-framing techniques in which lumber use is optimized, saving material and improving the energy performance of the building envelope.

Air barrier: Building assembly components that work as a system to restrict air flow through the building envelope an air barrier may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both.

Air handler: Fan that a furnace, whole-house (central) air-conditioner, or heat pump uses to distribute heated or cooled air throughout the house.

Air-source heat pump: Heat pump that relies on outside air as the heat source and heat sink; not as effective in cold climates as ground-source heat pumps.

Airtight drywall: Use of drywall with carefully sealed edges and joints that serves as an interior air barrier in building assemblies.

Albedo: Percentage of light reflected off a surface; a material with high albedo is very reflective.

Ammonium sulfate: Flame retardant commonly used in cellulose insulation. Borates are also used.

Annual fuel utilization efficiency (AFUE): Energy efficiency of a heating system that accounts for start-up, cooldown, and other operating losses that occur during operation; AFUE is always lower than combustion efficiency.

Asbestos: Mineral fiber once commonly used in building materials, including insulation, fireproof siding, and resilient flooring; a known human carcinogen (causing lung cancer), asbestos is no longer used in the United States.

Autoclaved aerated concrete (AAC): Masonry building material made of portland cement, sand, and water in an autoclaving process (heating under pressure), which the setting results in the production of air pockets in the material, making it less dense and better insulating. AAC has been used throughout much of the world for more than 70 years.

Backdrafting: Indoor air quality problem in which potentially dangerous combustion gases escape into the house instead of going up the chimney.

Balanced ventilation: Mechanical ventilation system in which fans exhaust stale indoor air and bring in fresh outdoor air in equal amounts; often includes heat recovery or heat and moisture recovery (see also heat recovery ventilator and energy-recovery ventilator).

Batch solar water heater: Solar water heater in which potable water is heated where it is stored. Also called an integral collector storage (ICS) solar water heater.

Binder: Glue used in manufacturing wood products, such as medium-density fiberboard (MDF), particleboard, and engineered lumber. Most binders are made with formaldehyde. See urea-formaldehyde binder and methyl diisocyanate (MDI) binder.

Bio-based material: Material made from living matter, such as agricultural crops. Bio-based materials are usually biodegradable.

Biophilia: Theory developed by biologist Edward O. Wilson suggesting that humans have an innate affinity for nature.

Blower door test: Test used to determine a home’s air tightness. A powerful fan is mounted in an exterior door opening and used to pressurize or depressurize the house. By measuring the force needed to maintain a certain pressure difference, a measure of the home’s air tightness can be determined. Operating the blower also exaggerates air leakage and permits a weatherization contractor to find and seal those leakage areas.

Blowing agent: Compound used in producing foam insulation. Mixed as a liquid with the foam ingredients under pressure, the blowing agent evaporates, creating gas bubbles that provide the insulation. Until recently, most blowing agents (HCFCs and CFCs) depleted Earth’s protective ozone later; except for extruded polystyrene, the industry has now switched to ozone safe blowing agents.

Boiler: System used to heat water for hydronic heating. Most boilers are gas-fired or oil-fired, although some are electric or wood-fired; a boiler can also heat water for domestic uses through a tankless coil or an indirect water heater.

Borate: Chemical containing the element boron that provides fire resistance to materials such as cellulose insulation and decay resistance to wood products.

Brominated flame retardant (BFR): Chemicals added to various plastics and foam materials to provide fire resistance. There is growing concern these are harmful to humans.

Btu: British thermal unit, the amount of heat required to raise one pound of water (about a pint) one degree Fahrenheit in temperature, about the heat content of one wooden kitchen match. One Btu is equivalent to 0.293 watt-hours or 1,055 joules.

Building envelope: Exterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation. The envelope includes the house foundation, framed exterior walls, roof or ceiling, and insulation and air-sealing materials.

Capillary forces: Forces that lift water or pull it through porous materials, such as concrete.

Carbon-neutral house: House that, on an annual basis, does not result in a net release of carbon dioxide (a greenhouse gas that contributes to global warming) into the atmosphere.

Cavity-fill insulation: Insulation installed in the space created by wall, ceiling, roof, or floor framing, most commonly fiberglass-batt, spray-applied or dense-pack cellulose, or spray polyurethane.

Chromated copper arsenate (CCA): Type of wood preservative that has now been largely eliminated from residential wood products because of concerns about leaching and toxicity. Huge quantities of CCA-treated wood remain in use, especially in residential decks.

Cistern: Vessel for storing water, such as that collected with a rainwater-harvesting system.

Cladding: Materials used to enclose a house, providing protection against weather.

Combustion efficiency: Efficiency at which a fuel is burned in a combustion appliance when operating at its rated output; the combustion efficiency is always higher than the annual fuel utilization efficiency (AFUE).

Commissioning: Process of testing a home after a construction or renovation project to ensure that all of the home’s systems are operating correctly and at maximum efficiency.

Compact fluorescent lamp (CFL): Fluorescent light bulb in which the tube is folded or twisted into a spiral to concentrate the light output. CFLs are typically three to four times as efficient as incandescent light bulbs and last eight to ten times as long.

Composite lumber: Lumber, typically decking, made from plastic (often high-density polyethylene) and wood fiber or other agricultural byproducts. Composite lumber often contains recycled content.

Composting system: Outdoor bins for converting vegetable scraps, garden trimmings, and other plant matter into a rich, high-organic-content soil amendment. An alternative for indoor use is a worm bin.

Concrete masonry unit (CMU): Block made of concrete used for wall construction. The hollow cores can be filled with concrete to reinforce walls.

Conduction: Movement of heat through a material as kinetic energy is transferred from molecule to molecule. The handle of an iron skillet on the stove gets hot due to heat conduction. R-value is a measure of resistance to conductive heat flow.

Convection: Movement of heat from one place to another by physically transferring heated fluid molecules, usually air or water. Natural convection is the natural movement of that heat; forced convection relies on fans or pumps.

Cripple studs: Studs in a wall system that support headers above (and below) windows or doors; indiscriminately placed, these additional studs can result in extra heat loss because they do not insulate as well as the insulation in the wall cavity.

Cross-linked polyethylene (PEX): Specialized type of polyethylene plastic that is strengthened by crosslinking (chemical bonds formed in addition to the usual bonds in the polymerization process). PEX is used primarily as tubing for hot and cold water distribution and radiant-floor heating.

Current loop: In electrical wiring, a situation in which separation of hot and neutral leads results in higher than normal electromagnetic fields (EMFs).

Curtain truss: Nonstructural truss that extends from a structural wall system solely for the purpose of holding cavity-fill insulation known also as a Larson truss. Often used on timber-frame houses and in superinsulation retrofits, curtain trusses may be as much as 12 inches deep, providing an insulating value greater than R-40. Since they aren’t structural, curtain trusses are often constructed from 2×2s with plywood reinforcement flanges to minimize wood use.

Daylighting: Use of sunlight for daytime lighting needs.

Degree day: Measure of heating or cooling requirements based on the average outdoor temperature. To calculate the number of heating degree days of a given day, find the average of the maximum and minimum outdoor temperatures and subtract that from 65°F. The annual number of heating degree days is a measure of the severity of the climate and is used to determine expected fuel use for heating. Cooling degree days, which measure air-conditioning requirements, are calculated by subtracting the average outdoor temperature from an indoor base temperature, usually 75°F.

Demand water heater: Water heater that heats water only as needed; there is no storage tank and thus no standby heat loss. Also called a tankless water heater.

Double wall: Construction system in which two layers of studs are used to provide a thicker-than-normal wall system to accommodate extra insulation. The two walls are often separated by several inches to reduce thermal bridging through the studs and to provide additional space for insulation.

Dual-flush toilet: Toilet that provides two flush levels: a full-volume flush for use with solid wastes and a reduced-volume flush (often half the volume) when only liquid waste and paper need to be flushed.

Duct blaster: Calibrated air-flow measurement system developed to test the airtightness of forced-air duct systems. All outlets for the duct system except for the one being tested are sealed off and the system is either pressurized or depressurized; the work needed by the fan to maintain a given pressure difference provides a measure of duct leakage.

Electric-resistance heat: Heat provided by electricity in which high-resistance wires convert electric current directly into heat. See also heat pump.

Electromagnetic field (EMF): Field given off by electric current flow. Some health experts are concerned that the magnetic field component of EMFs may be harmful or even cause cancer. Magnetic fields are stronger near current in which there is separation between the positive and neutral leads.

Embodied energy: Energy that goes into making a product, including energy for transporting both the raw materials and the finished product.

Endocrine disruptor: Chemical that mimics natural hormones, such as estrogen, and may interfere with reproductive development or alter. Endocrine disruptors include such commonly used chemicals as phthalate plasticizers (used in PVC plastic), and bisphenol-A (used in epoxies and polycarbonate plastic).

Energy efficiency rating (EER): Operating efficiency of a room air-conditioner, measured in Btus of cooling output, divided by the power consumption in watthours; the higher the number, the greater the efficiency.

Energy factor: Efficiency measure for rating the energy performance of dishwashers, clothes washers, water heaters, and certain other appliances; the higher the number, the greater the efficiency. A “modified energy factor” accounts for certain adjustments according to accepted test procedures.

Energy Star: Labeling system sponsored by the U.S. Environmental Protection Agency and the U.S. Department of Energy for labeling the most energy efficient products on the market. The ratings apply to a wide range of products, from computers and office equipment to refrigerators and air-conditioners.

Energy-efficient mortgage (EEM): Special type of mortgage in which the lending institution raises the allowable mortgage amount for a given earnings level, since energy saving features in the house will reduce the monthly operating costs, thus leaving more money available to pay the mortgage.

EnergyGuide: Label from the Federal Trade Commission that lists the expected energy consumption of an appliance, heating system, or cooling system and compares consumption with other products in that category, The energy performance is based on specified operating conditions and average energy costs; actual performance may vary.

Energy-recovery ventilator (ERV): Type of heat-recovery ventilator (HRV) that captures water vapor as well as heat from the outgoing airstream in a balanced ventilation system. In winter months, this can reduce the drying that occurs when outdoor air is brought indoors and warmed.

Engineered lumber: Lumber made by gluing together veneers or strands of wood to create very strong framing members. Stronger and less prone to warping than standard framing lumber, it can be made from smaller-diameter trees, saving old-growth forests.

Evaporative cooler: Energy-efficient cooling system in which a fine mist of water is evaporated, lowering the air temperature. Evaporative coolers are most appropriate in dry climates, becauses they add humidity to a house. Also known as a swamp cooler.

Exhaust-only ventilation: Mechanical ventilation system in which one or more fans are used to exhaust air from a house, with make-up air supplied passively. See also balanced ventilation.

Expanded polystyrene (EPS): Type of rigid foam insulation. Unlike extruded polystyrene (XPS), EPS does not contain ozone depleting HCFCs.

Extruded polystyrene (XPS): Type of rigid foam insulation that is widely used below grade, such as underneath concrete floor slabs, In North America XPS is currently made with ozone-depleting HCFC- 142b.

Fan-coil: Electric or hydronic heating or cooling element installed in a duct. In a highly energy-efficient home, fan coils in ventilation ducting can be used for heating or cooling the living space.

Fiber-cement siding: Siding material made from wood fiber and portland cement that is highly durable, moisture resistant, and fire proof. Developed in New Zealand, the material is becoming common as a siding material in North America.

First cost: Initial cost of buying or building something, as distinguished from the operating cost.

Flashing: Material, usually sheet metal, rubber, or plastic, installed to keep rain from entering a building. When properly installed in a wall or roof assembly, flashing sheds rain to the exterior.

Fluorescent lighting: Type of energy-efficient lighting introduced in the 1930s in which electric discharge within a sealed glass tube energizes mercury vapor, producing ultraviolet (UV) light, which is absorbed by a phosphor coating, which in turn fluoresces, generating visible light. See also compact fluorescent lamp.

Forced-air heating: Heat distribution system in which heat is delivered by forcing warm air through a network of ducts. A furnace or heat pump typically generates the warm air.

Forest Stewardship Council (FSC): Nonprofit organization that promotes forestry practices that are sustainable from environmental, economics and social standpoints. FSC certification on a wood product is an indicator that the wood came from a well-managed forest.

Formaldehyde: Chemical found in many building products; most binders used for manufactured wood products are formaldehyde compounds. Reclassified by the United Nations International Agency for Research on Cancer (IARC) in 2004 as a known human carcinogen. See also phenol-formaldehyde binder and urea-formaldehyde binder.

Friable: Ability of a solid material to break down or disintegrate. A friable insulation material may lose its effectiveness; some friable materials release hazardous dust into a house.

Fuel cell: Electrochemical device similar to a battery in which electricity is generated by chemically reacting hydrogen with oxygen, producing electricity, water vapor, and heat.

Furnace: System used to heat air for a forced-air heating system. Furnaces can be gas-fired, oil-fired, wood-fired, or electric.

Glazing: Transparent or translucent layer of window or door that transmits light.High-performance glazings may include multiple layers of glass or plastic, low-emissivity (low-e) coatings, and low-conductivity gas fill.

Global warming potential: Measure of how a given mass of greenhouse gas is estimated to contribute to global warming compared with carbon dioxide, which is given a value of 1.0 on this relative scale.

Gravity-flush toilet: Toilet whose flush is powered solely by the force of falling water. See also pressure-assist toilet.

Graywater: Wastewater from a building that does not include flush-water from toilets or (as most commonly defined) water from kitchen sinks or dishwashers. In some places, graywater can be collected and used for subsurface irrigation.

Green building: Design and construction of buildings that minimize impacts on the environment while helping keep occupants healthy.

Green electricity: Electricity generated from renewable energy sources, such as photovoltaics (solar power), wind power, biomass, and small-scale hydropower. (Large, conventional hydropower sources usually are not included in definitions of green electricity.)

Grid-connected power system: Electricity generation system, usually relying on photovoltaics or wind power, that is hooked up to the utility company’s electric grid through a net-metering arrangement so that electricity can be obtained when the locally generated power is not sufficient. See also stand-alone power system.

Ground-source heat pump: Heat pump that relies on the relatively constant temperatures underground as the heat source and heat sink. The energy performance of ground-source heat pumps is usually better than that of air-source heat pumps.

Gut rehab: Building renovation in which the walls are gutted (reduced to the wall framing and sometimes sheathing), then insulated, sheathed, and finished.

Heat exchanger: Device that allows for transfer of heat from one material to another. An air-to-air heat exchanger, or heat-recovery ventilator, transfers heat from an outgoing airstream to an incoming airstream. A copper-pipe heat exchanger in a solar water heater tank transfers heat from the heat-transfer fluid circulating through a solar collector into the potable water in the storage tank.

Heat pump: Heating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump.

Heat distribution: System for delivering heat throughout a house. See forced-air heating and hydronic heating.

Heat-recovery ventilator (HRV): Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger. See also energy-recovery ventilator.

High-efficiency toilet (HET): Toilet that provides at least 20% water savings over the federal standard of 1.6 gallons per flush and still meets the most rigorous standards for flush performance.

Home performance audit: An energy audit that also includes inspections and testing assessing moisture flow, combustion safety, thermal comfort, indoor air quality, and durability.

Home run plumbing system: Water distribution piping system in which individual plumbing lines extend from a central manifold to each plumbing fixture or waterusing appliance. The piping is typically cross-linked polyethylene (PEX). Because diameter of the tubing can be matched to the flow of the fixture or appliance, hot water can be delivered more quickly.

Horizontal-axis clothes washer: Washing machine (typically front-loading) in which the laundry drum is configured horizontally. This design allows significant water savings, because the laundry is dipped into and out of the wash water as the drum rotates. See also vertical-axis clothes washer.

Hydrochlorofluorocarbon (HCFC): Compound commonly used as a refrigerant in compression-cycle mechanical equipment (refrigerators, air-conditioners, and heat pumps) or as a blowing agent in producing foam insulation. HCFCs are damaging to Earth’s protective ozone layer.

Hydronic heating: Heat distribution system in which hot water produced by a boiler is circulated through pipes and baseboard radiators or tubing in a radiant floor. Also called baseboard hot-water heating.

Impervious surface: Surface that does not permit stormwater runoff to infiltrate the ground. See also porous paving.

Incandescent light: Light produced when electric current heats a tiny coiled filament to glowing. Such light bulbs convert about 90% of the electricity into heat and only 10% into light. See also fluorescent lighting.

Indirect water heater: Water heater that draws heat from a boiler used for space heating. The boiler heats water in a separate, insulated tank via a water-to-water heat exchanger. See also tankless coil.

Indoor air quality (IAQ): Healthfulness of an interior environment. IAQ is affected by such factors as moisture and mold, emissions of volatile organic compounds from paints and finishes, formaldehyde emissions from cabinets, and ventilation effectiveness.

Insulated concrete form (ICF): Hollow insulated forms, usually made from expanded polystyrene (EPS), used for building walls (foundation and above ground), that are stacked and stabilized and then filled with concrete, which provides the wall structure.

Integral collector storage (ICS) solar water heater: Solar water heater in which potable water is heated where it is stored.

Integrated design: Building design in which different components of design, such as the building envelope, window placement and glazings, and mechanical systems, are considered together. High-performance buildings and renovations can be created cost effectively using integrated design, since higher costs in one place can often be paid for through savings elsewhere. For example, by improving the performance of the building envelope, the heating and cooling systems can be downsized or even eliminated.

Inverter: Device for converting direct-current (DC) electricity into the alternating-current (AC) form required for most home uses. An inverter is necessary if home-generated electricity is to be fed into the electricity grid through a net-metering arrangements.

Kilowatt-hour (kWh): Measure of electricity consumption; a 100-watt light bulb burning for ten hours consumes 1 kWh.

Leaching: Process by which chemicals can escape from certain materials in the environment;. For example, arsenic can leach out of older pressure-treated wood.

Lead: Toxic heavy metal often found in paints made or applied before 1978. When renovating, follow proper lead-abatement procedures to avoid lead poisoning.

LEED for Homes: Rating system for green homes developed by the U.S. Green Building Council. The acronym stands for Leadership in Energy and Environmental Design.

Life cycle: Entire life of a product or material, from raw material acquisition through disposal.

Life-cycle assessment (LCA): Examination of the environmental and health impacts of a product or material over its life cycle. LCA provides a mechanism for comparing different products and materials for green building.

Life-cycle cost (LCC): Economic cost of a product or building over its expected life, including both first cost (purchase cost) and operating cost.

Light-emitting diodes (LEDs): Small lights that use semiconducting (solid-state) materials to turn electricity into light. Different semiconductors create different colors of light. White LEDs appropriate for residential use are continuously improving in quality, efficacy, and cost-effectiveness. LEDs are very long lasting; unlike fluorescent lamps, they do not contain mercury.

Light organic solvent preservatives (LOSPs): Organic pesticides, biocides, and fungicides suspended in a hydrocarbon (solvent-based) carrier. “Organic” in this case refers to the fact that the chemicals are carbon based.

Light pollution: Nighttime lighting that escapes into the night sky. Light pollution can interfere with the day-night patterns of ecosystems, disrupt the flights of migrating birds, interfere with sea turtle nesting in coastal areas, and hinder astronomical observation.

Low-conductivity gas fill: Transparent gas installed between two or more panes of glass in a sealed, insulated window that resists the conduction of heat more effectively than air. The fill boosts a window’s R-value and reduces its U-factor.

Low-emissivity (Low-e) coating: Very thin metallic coating on glass or plastic window glazing that reduces heat loss through the window. The coating emits less radiant energy (heat radiation), which makes it, in effect, reflective to that heat. The coating boosts a window’s R-value and reduces its U-factor.

Make-up air: Outside air supplied to replace household air that was used in a combustion appliance or exhausted through a ventilation system.

Manifold: Component that distributes the water in a home-run plumbing system. It has one inlet and many outlets, each of which feeds one fixture or appliance.

Mechanical ventilation: Ventilation system using one or more fans to exhaust stale indoor air from a home as a way to ensure adequate indoor air quality. See exhaust only ventilation and balanced ventilation.

Medium-density fiberboard (MDF): Panel product used in cabinets and furniture, generally made from wood fiber glued together with binder. Similar to particleboard, MDF has finer texture, offering more precise finishing. Most MDF is made with formaldehyde-emitting ureaformaldehyde binders.

Methyl diisocyanate (MDI) binder: Nonformaldehyde binder used in some medium-density fiberboard and particleboard products, including straw-based particleboard.

Net metering: Arrangement through which a homeowner who produces electricity using photovoltaics or wind power can sell excess electricity back to the utility company, running the electricity meter backward. The utility effectively buys the power at the retail price, but the amount of electricity the utility company will “buy” in a given month is limited to the amount that the homeowner buys; any excess electricity is purchased at a much lower, wholesale price. See grid-connected power system.

Net-zero energy: Producing as much energy on an annual basis as one consumes on site, usually with renewable energy sources, such as photovoltaics or small-scale wind turbines. Calculating net-zero energy can be difficult, particularly in grid-tied renewable energy systems, because of transmission losses in power lines and other considerations.

Offgassing: Release of volatile chemicals from a material or product. See also volatile organic compounds.

On-center: As used in house construction, the distance from the center of one framing member to the center of another. In wood-frame construction, studs are typically 16 or 24 inches on-center.

On-demand hot water circulation: System that quickly delivers hot water to a bathroom or kitchen when needed, without wasting the water that has been sitting in the hot-water pipes, which circulates back to the water heater.

On-site wastewater system: Treatment and disposal of wastewater (sewage) from a house that is not connected to a municipal sewer system; most on-site systems include a septic tank and leach field.

Operating cost: Cost of operating a device or building; including energy, maintenance, and repairs.

Operating energy: Energy required to operatea device or building.

Oriented-strand board (OSB): Wood sheathing or subfloor panel made from strands of wood glued together in layers oriented for strength. Most OSB is made using phenol-formaldehyde or methyl diisocyanate (MDI) binder.

Ozone depletion potential: Amount of damage to the ozone layer a given chemical can cause compared trichlorofluoromethane (CFC-11), which is given a value of 1.0 on this relative scale.

Particleboard: Panel product used in cabinets and furniture, generally made from wood fiber glued together with binder. Similar to mediumdensity fiberboard (MDF), a coarser texture. Most particleboard is made with formaldehyde-emitting urea-formaldehyde binder, although some wood particleboard and all straw particleboard use a nonformaldehyde methyl diisocyanate (MDI) or lowemitting phenol-formaldehyde binder.

Passive solar heating: Building design in which solar energy provides a significant portion of the heating without fans or pumps; the building itself serves as the solar collector and heat storage system.

Payback period: Length of time it takes for an investment to pay for itself. For example, water and energy savings from replacing an old showerhead with a new, water-saving model can often pay back the investment in a few months; the payback period for a photovoltaic power system will be much longer.

Peak watt: Highest possible unit of rated power output, (for example, from a photovoltaic (PV) module in full sunlight), as distinct from its output at any given moment, which may be lower.

Pellet stove: Wood stove designed to burn pellets made from compressed sawdust or wood shavings which are fed into the firebox at a metered rate by a screw auger. An electric fan provides combustion air.

Phenol-formaldehyde binder: Formaldehyde-based binder used for wood products, especially those made for exterior applications. It generally has lower formaldehyde emissions than urea-formaldehyde binder.

Photovoltaics (PV): Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow.

Phthalate plasticizer: Chemical added to polyvinyl chloride (PVC) and certain other plastics to make them more flexible; some phthalates are known or thought to be endocrine disruptors. See endocrine disruptors.

Pier foundation: Building foundation consisting of piers instead of continuous walls. Piers are resource-efficient because they avoid the need for continuous foundation walls.

Plasticizer: Chemical compound added to a material to make it more flexible or softer. See phthalate plasticizer.

Polyisocyanurate (polyiso): Type of rigid foam insulation used in above-grade walls and roofs, typically with a foil facing on both sides. This kind of insulation was made with ozone-depleting HCFC-141b blowing agent, but manufacturers have switched to ozone-safe hydrocarbons.

Polyurethane foam: Insulation material made from polyol and isocyanate and a blowing agent that causes it to expand, typically sprayed into wall cavities or sprayed on roofs. Both open-cell and higher-density closed-cell products are used.

Polyvinyl chloride (PVC): Most common plastic in building construction, widely used in such applications as drainage piping, flooring, exterior siding, window construction, and electrical wire. Also known as vinyl.

Porous paving: A paving material that allows precipitation to percolate through and infiltrate the ground rather than contributing to storm water runoff. Pavers can be asphalt, concrete, or porous grid.

Portland cement: Building material made from limestone, gypsum, and shale or clay, which when mixed with water, binds sand and gravel into concrete. Portland cement was invented in 1824 by Joseph Aspdin, a British stone mason, who named it after a natural stone quarried on the Isle of Portland off the British coast.

Postconsumer recycled material: Material recovered from a waste product that has been in use by a consumer before being discarded. See also postindustrial recycled material.

Postindustrial (preconsumer) recycled material: Material recovered from the waste stream of an industrial process that has not been placed in use. See also postconsumer recycled material.

Potable water: Water considered safe for drinking and cooking.

Pozzolan: Any silicon or silicon-aluminum material – which when finely divided and mixed with moisture, reacts with calcium hydroxide to form a cementitious compound. Common examples of pozzolans include fly ash, blast furnace slag, volcanic ash, silica fume, and rice hull ash.

Pressure-assist toilet: Toilet that uses air pressure, generated as the toilet tank refills, to produce a more forceful flush; some high-efficiency toilets (HETs) rely on pressure-assist technology.

Pressure-treated wood: Wood that has been chemically treated to extend its life, especially when outdoors or in ground contact. The most common pressure treated wood until a few years ago, chromated copper arsenate (CCA), has now been phased out for most applications, because of health and environmental concerns. Other pressure-treating chemicals include ACQ, copper azole, and sodium silicate.

Prudent avoidance: Strategy using relatively easy and low-cost tactics to avoid exposure to something that may prove to be harmful, such as electromagnetic fields (EMFs).

R-value: Measure of resistance to heat flow; the higher the R-value, the lower the heat loss. R-value is the inverse of U-factor.

Radiant energy: Energy transmitted by electromagnetic waves.

Radiant-floor heating: Heat distribution system in which a floor serves as a low-temperature radiator. When used with hydronic heating, hot water is usually circulated through tubing embedded in a concrete slab; alternatively, the tubing can be installed on the underside of wood subflooring, although the benefit of thermal mass is lost.

Radiation: Movement of energy via electromagnetic waves.

Radon: Colorless, odorless, short-lived radioactive gas that can seep into homes and create lung cancer risk. Radon and its decay products emit cancer causing alpha, beta, and gamma particles.

Rainscreen: Construction detail appropriate for all but the driest climates to prevent moisture entry and to extend the life of siding and sheathing materials, most commonly produced by installing thin strapping to hold the siding away from the sheathing by a one-quarter to three-quarters of an inch.

Raised heel truss: Preconstructed roof truss designed to allow room at the eaves (above exterior walls) for large amounts of insulation. (Standard roof trusses have sufficient depth for adequate insulation near the eaves.)

Rankine-cycle compressor: Technology used in a standard air-conditioner and refrigerator to achieve cooling, in which a refrigerant is alternately compressed and allowed to expand, cooling air in the process.

Reflective roofing: Roofing material that reflects most of the sunlight striking it to help reduce cooling loads. The Energy Star Cool Roof program certifies roofing materials that meet specified standards for reflectivity.

Refrigerant: Compound used in refrigerators, air-conditioners, and heat pumps to transfer heat from one place to another (using the Rankine cycle), thus cooling or heating a space. Most refrigerants today are hydrochlorofluorocarbons (HCFCs), which deplete the ozone layer.

Renewable energy: Thermal or electrical energy produced using solar, wind, hydropower, or biomass energy sources.

Room air-conditioner: Air-conditioner installed in a window or through a wall, usually used to cool a relatively small area. With a very energy efficient, tight house, a single room air-conditioner may be able to cool the entire space. See also whole-house (central) air-conditioner.

Sealed combustion: Combustion system for space heating or water heating in which outside combustion air is fed directly into the combustion chamber and flue gases are exhausted directly outside.

Seasonal energy efficiency ratio (SEER): Energy performance rating of a whole-house (central) air conditioner or heat pump operating in the cooling mode, calculated as the ratio of the estimated seasonal cooling output divided by the seasonal power consumption in an average climate.

Sheathing: Material, usually plywood or oriented-strand board (OSB) but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses. Siding or roofing installed on the sheathing, sometimes over strapping to create a rainscreen.

Solar collector: Device for capturing solar energy and transferring heat to water or air that circulates through it.

Solar gain: Sunlight entering a building. A passive solar direct-gain system uses solar gain.

Solar heat gain coefficient (SHGC): The fraction of solar gain admitted through a window, expressed as a number between 0 and 1.

Space planning: Process of converting the needs expressed by the client into the drawings and supporting documentation that outline the plan for the team. For the interior designer, space planning includes the placement of all fixed and unfixed elements, from plumbed and wired appliances to furniture and the way people move around in the space. Plumbing and HVAC contractors are concerned primarily with hidden elements. With comprehensive space planning, the team works together to ensure that the design is optimized across disciplines.

Stormwater: Runoff from precipitation that is either carried off site in storm sewers or allowed to infiltrate the ground; stormwater can be reduced through the use of porous paving and other infiltration strategies.

Structural insulated panel (SIP): Building panel usually made of oriented-strand board (OSB) skins surrounding a core of expanded polystyrene (EPS) foam insulation. SIPs can be erected very quickly with a crane to create an energy efficient, sturdy home.

Sump: Reservoir or pit in the basement of a house into which water can drain, especially during flooding. A sump pump is used to pump collected water out of this reservoir.

Sun tempering: Practice of using a modest area of south facing windows to provide limited passive solar heating to a house.

Superinsulate: To insulate extremely well. A house with very efficient windows and tight construction results in very low heating and cooling costs.

Swale: Low area of ground used for drainage and often the infiltration of stormwater.

Tankless coil: Heat exchanger used for heating water that is integrated into a boiler. Effective in the winter months when the boiler is operating for space heating, tankless coils waste energy in warmer months, since they require the boiler to fire up every time hot water is drawn.

Therm: Unit of heat equal to 100,000 British thermal units (Btus), commonly used to measure natural gas consumption.

Thermal bridging: Heat flow that occurs across more conductive components in an otherwise well-insulated material, resulting in disproportionately significant heat loss. For example, steel studs in an insulated wall dramatically reduce the overall energy performance of the wall because of thermal bridging through the steel.

Thermal mass: Heavy, high-heat-capacity material that can absorb and store a significant amount of heat; used with a passive solar heating system to keep the house warm at night.

Thermosiphon solar water heater: Solar water heater that operates passively (through natural convection), circulating water through a solar collector and into an insulated storage tank situated above the collector. Pumps and controls are not required.

Top plate: Wood framing member that forms the top of a wall. In advanced framing, a single top plate is often used in place of the more typical double top plate.

Track-off mat: Mat at a house entrance across which people scuff their feet to remove moisture, dirt, and other particulates, keeping contaminants out and reducing cleaning requirements.

Tubular skylight: Round skylight that transmits sunlight down through a tube with internally reflective walls, even through an attic space to deliver daylighting through a ceiling light diffuser. Most tubular skylights are 12 to 16 inches in diameter and deliver daytime lighting comparable to several 100-watt incandescent light bulbs.

U-factor: Measure of the heat conducted through a given product or material calculated as the number of British thermal units (Btus) of heat that move through a square foot of the material in one hour for every one degree Fahrenheit difference in temperature across the material (Btu/ft2°F hr). U-factor is the inverse of R-value.

United States Green Building Council (USGBC): Organization devoted to promoting and certifying green buildings. USGBC created the LEED rating systems.

Universal design: Design that makes a building accessible to as many individuals as possible, including older people and those with physical challenges.

Unvented (or vent-free) gas heater: Gas-burning space heater that is not vented to the outdoors. Although unvented gas heaters burn very efficiently, indoor air quality experts strongly recommend against their use because combustion gases, including high levels of water vapor, are released into the house.

Urea-formaldehyde binder: Interior-grade, formaldehyde based binder used for particleboard, medium-density fiberboard (MDF), and hardwood plywood. This type of binder generally has higher formaldehyde emissions than phenol-formaldehyde binder.

UV light treatment: Water treatment system in which water passes through a column where it is exposed to ultraviolet light to kill any pathogens.

Vapor diffusion: Movement of water vapor through a material. Water vapor can diffuse through even solid materials if the permeability is high enough.

Vapor profile: The relative individual component and total combined vapor permeability of building assemblies. The vapor profile addresses not only how the assembly protects itself from getting wet by vapor diffusion, but also how it dries the assembly gets wet.

Vapor retarder: Layer that inhibits vapor diffusion through a building envelope. Examples include polyethylene sheeting, foil facing, kraft paper facing on batt insulation, and low-permeability paints. Most building codes define a vapor retarder as 1 perm or less, with many common vapor retarders being significantly less than 1 perm. Note that many building scientists prefer a focus on the vapor profile of a building assembly rather than just the individual vapor permeability of the designated vapor retarder.

Variable air volume (VAV) air handler: System for controlling an HVAC system in which the volume of air provided to conditioned space is varied to control comfort.

Ventilation: Replacement of stale indoor air with fresh outdoor air, usually with fans but sometimes naturally through building design elements. See also heat recovery ventilator.

Vertical-axis clothes washer: Top-loading washing machine with a tub that rotates back and forth and spins on a vertical axis, such that the center of rotation is a line extending up from the center of the tub. See also horizontal-axis clothes washer.

Vinyl: Common term for polyvinyl chloride (PVC), a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate).

Volatile organic compound (VOC): Organic compound that evaporates readily into the atmosphere. As defined by the U.S. Environmental Protection Agency, VOCs are organic compounds that volatize and then contribute to photochemical smog production.

Waste management plan: Plan that addresses the collection and disposal of waste generated during construction or renovation, usually including the collection and storage of recyclable materials.

Wastewater: Used water from toilets, showers, sinks, dishwashers, clothes washers, and other sources in the home, including all contaminants, which can either flow into a municipal sewer system or be treated with an onsite wastewater disposal system. See also graywater.

WaterSense: Program developed and administered by the U.S. Environmental Protection Agency to promote and label water-efficient plumbing fixtures.

Weatherization: Cost-effective energy efficiency measures for existing residential and multifamily housing. When weatherization includes the house as a system, it is often called whole-house weatherization.

Whole-house (central) air-conditioner: Air-conditioning system that serves an entire house; cooled air is delivered through a system of ducts. See also room air-conditioner.

Whole-wall R-value: Average R-value of a wall, taking into account the thermal bridging through wall studs.

Xeriscaping: Type of landscaping that requires little if any irrigation, is suited to dry and drought-prone climates, and generally relies on regionally adapted native plants.

They say a picture is worth 1,000 words, so before you leave be sure to visit Von Löwen Designs to view an assortment of refreshing examples in kitchen and bath design concepts, refined palette and interior finishes, and sustainable yet chic, green remodeling ideas that may encourage and inspire your next remodel or home improvement project.