|Green Home Vocabulary
Many folks have been working for many years to improve
the quality of the homes we build. You will find many names for similar programs
as you start to collect information on what many now call Green Homes. Here
is a list of some common vocabulary used to describe these homes.
Housing - should be affordable to buy and maintain
Air Tight Homes
- Well sealed homes, tested with a blower door. Typical existing homes have
more than 5 air changes per hour (ACH) under test conditions. Energy Star
homes have to be below 5. Many builders achieve 2 to 3 ACH. Passive
Homes have to be less that 0.6. Airtight homes should be mechanically ventilated.
Energy Efficient Home
- a vague term, used freely by sellers of homes.
- have to be at least 20 to 30% more efficient than code. To be Energy Star,
the home has to be "rated" by a third party - including testing for air
tightness. A step in the right direction.
- The practice of 1) improving the efficiency with which buildings and their
sites use energy, water and materials, and 2) reducing building impacts on
human health and the environment through better siting, design, construction,
operation, maintenance and removal the complete building lifecycle.
The Office of the Federal Environmental Executive
Green Homes - the
latest general term to describe a home designed to be environmentally friendly,
including energy and water efficiency, healthy and more.
Model Energy Code
- minimum building requirements, the worst home you can legally
build. If your builder claims that they build "energy efficient homes",
as they build to the new building code, look for another builder!
Passive Homes combine
super insulation and air sealing techniques so that the home does not require
a conventional heater. This usually means a 90% reduction is heat loss from
the home. There are very specific performance requirements for Passive Homes.
I consider Passive Homes to be the Holy Grail of low energy homes!
Homes designed to take advantage of the position of the
sun through the seasons to keep the home comfortable. Orienting most of the
windows and the long side of the house toward the winter sun is a classic
feature of passive solar homes. They should also include very well insulated
walls, overhangs designed to allow winter sun to enter while blocking out
summer sun, and thermal mass to moderate temperatures. There are no standards
for passive solar homes.
Solar Homes a generic
term meaning that energy from the sun is being used for something in the
home. This could be solar hot water, solar hot air, solar electric or passive
Superinsulated (SI) Homes
again a generic term that means using much more insulation
that required by code. To be considered Superinsulated today, I would say
you need to have at least R-40 walls and R-60 ceilings. Building this way
can save 50% or more of the annual energy costs for heating and cooling compared
to a standard home, and is also more comfortable and healthy for the occupants.
-meets the needs of the present without compromising
the ability of future generations to meet their own needs. The
UN World Commission on Environment and Development
Whole Building Design
- an early term for using a systems approach to home design.
Zero Energy Homes
produce as much energy as they consume in a typical year. The lowest cost
approach to ZEHs is to first build close to the Passive Homes standard, then
add renewables (usually solar electric and solar hot water).