Renewable Energy recommends setting the following general “green building” goals that can be applied to redesign virtually any construction project if you get into the process early enough. While these recommendations pertain largely to residential construction, much of the information is also applicable to light-commercial construction. Note: these recommendations are not to be used as design standards, and for best performance of environmental building strategies we recommend professional technical support for most projects.
The following measures have been found in most cases to increase construction costs by less than 10%. Your resulting project will be comfortable, more durable, healthy to live in, less costly to operate while helping protect our environment. Obviously, there are more details to a true “environmental building” project but this listing will help get you started.
Environmental Building Design and Construction Basics
- Consider building/home sites located nearer the workplace and essential services, or at least near public transportation to reduce expense and environmental burden of commuting by single-occupancy vehicles. [Buying an “affordable” home in a remote location promotes sprawl and may actually be less economically viable over its useful life when you include commuting costs].
- Can you deconstruct or refurbish an existing home/office or school rather than building a totally new structure for the same end result? Start by understanding the condition and location of an existing building or site before demolition is elected. [Lessens the overall impact of development by reuse of “embodied energy”].
- Select/layout building site with an emphasis on good drainage, no known in-ground pollutants, and to promote useful solar access. [no cost].
- Create an energy-efficient thermal envelope with appropriate insulation for your climate; using a whole-systems approach. For most parts of the U. S. the Department of Energy recommends at least R-38 for ceilings, R-21 walls, R-10+ foundations, and insulated doors. Coordinate this task with window selection. [R-factor is a measure of the resistance of materials to heat flow, higher numbers ~ less heat flow].
- Design moisture “forgiving” walls and roof details that repel rain and can dry out (1).
- Demand air-sealed construction with mechanical ventilation [cheap insurance against poor comfort and mold problems] Who says “Build it tight, ventilate right”? EEBA (1).
- Select the most appropriate window system for your climate to complement the homes insulation package; sometimes very efficient windows can lower the first costs of insulating a home [ask the builder, or their energy consultant, to see the calculations].
- Design for 35% – 40% passive solar heating with minimal A/C penalty [computer analysis recommended] (2).
- Layout the windows, glazed doors, and skylights to encourage daylighting of most rooms [no cost] (2).
- Specify and install high-performance mechanical equipment and distribution [heating and AC, and hot water supply]
- “Right size” mechanical equipment; require system analysis by the contractor — reduced system size from other efficiencies often pays for the upgrade to better heating and A/C performance [can save on the first cost, in most cases].
- Locate all forced-air ducts inside the conditioned spaces [minimal cost – up-front design decision].
- Air ducts for heating and cooling must be well sealed (1) with Mastic; testing is preferred for best performance of forced-air systems [minimal cost – job-site supervision].
- Consider digital thermostat (or EMCS) to control each zone of the building [inexpensive, can save 10% to 15% on heating and cooling costs].
- Consider solar hot water system with a heat recovery device, [may yield ~ 60% efficiency]; avoid low cost but expensive and pollution-intensive direct electric water heating.
- Install ceiling fans in major rooms [low-cost means to improve comfort; air flow allows seasonally higher or lower thermostat settings to feel comfortable].
- Forget the “fireplace,” select an air-tight woodstove with outside air supply [alt. Built-in “Masonry heater” specifically designed to save energy].
- Install most efficient EnergyStar™ major appliances [refrigerator, clothes washer, dish washer] (3).
- Select a high-performance electric lighting package. [hard wire fluorescent fixtures in main rooms, avoid too many ceiling “cans” that add to air leakage; occupancy sensors in utility areas, stairwells, and closets].
- Specify low/no VOC emission building products [adhesives, sealer, paint, cabinets, etc should not produce much “off-gassing” of harmful or irritating chemicals] (4).
- Utilize at least 50% documented “sustainable” wood products, preferably from 250 mi. radius of the building site (4).
- Install Radon-gas preventive foundation design [EPA or local health dept. guidance].
- Employ water conservation considering: tap flow controls, 1.2 gpf dual-mode toilets; or composting toilets [can you get by with one or one and 1/2 bathrooms?] consider omitting exterior wall hose-bibs; and instead install greywater recovery system for drip-watering landscaping.
- Finish with light color exterior finishes and high-reflectance roof covering [little-added cost for lighter colors].
- Plant (or “land-bank” on site during grading) native trees near buildings for shading, consider Xeric landscape species that require less watering; reduce overall areas of lawn [less need for fertilizers, weed control, and irrigation].
- Install driveways and walks using moisture pervious surfaces, avoiding impermeable asphalt [basically oil mixed with pebbles, also their dark surfaces add to “heat-island” effects]. If concrete is used, ensure it is additive free and mixed to provide a light color finish.
- EEBA “Builder Guide” (enter the bookstore, select your climate), 1998-2000 http://www.eeba.org
- NREL “Energy-10” computer software, training and manual http://www.sbicouncil.org
- ACEEE “Consumer Guide to Home Energy Savings, 7th Edition.” 2000 http://aceee.org/consumerguide/mostenef.htm
- Environmental Building News – “Product Directory” http://www.buildinggreen.com