Design considerations for LEED-H
On October 13th Shelter’s own John Barbour presented the closing keynote lecture at the American Institute of Architects (AIA) South Dakota Convention. John compared the design of 2 very different homes – one modern and the other Victorian, both LEED-H certified. One was the first LEED-H Platinum home in Minnesota (5ive), and the other was the first LEED-H restoration in Minnesota (Tricker-Hess). Here is a summary of his talk.
How does LEED define a green home?
LEED recommends that a home’s site, material usage, indoor air quality, energy usage, and water usage all be considered in order to provide a home that is healthy, comfortable, durable, energy efficient and environmentally responsible. Essentially LEED is a system that assigns points to various sustainable strategies.
These two designs used a common checklist based on the broad LEED definition of a green home.
Site | Materials | Energy | Air Quality | Conservation | Transportation | Alternative Energy
The first thing to consider is location, location, location. Is it an existing home or a new home on an infill lot? Is it in a new high-density community? Does the site have good access to services, utilities and public transportation? These location issues are given points by LEED-H.
Always design with care. Look for existing natural features to be retained and designed with or around – such as trees, grades and water. Manage and prevent soil erosion during construction and long-term. Find ways for the home and/or trees be located so the home is shaded in summer. Manage surface water runoff by designing the slopes, rainwater garden, green roof, pervious paving. Keep rain water and even gray water captured and used on site.
Working with an existing home, look for existing materials to salvage and re-used. Minimize waste during construction. Utilize advanced framing techniques: optimize wall design with smaller studs, larger stud spacing, continuous insulation, drainage layer under exterior finish, etc. Is wood always the best construction material? Research and use appropriate alternative materials: cement board siding, composite trim for interior and exterior, consider concrete walls. Always be on the hunt for recycled products or products made from recycled materials. Don’t forget about the scrap materials. Find suppliers who use finger-jointed trim (made from small pieces). Check for materials with third party oversight such as FSC or canadian Wood Council certified wood products.
You often hear the question, “How much insulation should I put in my house?” The answer is surprisingly simple, “More.” In a cold climate like the Midwest you should put as much of the best suited insulation as you can into your basement floor, walls and roof. It is that simple. We really like spray foam insulation to eliminate air movement through wall. Another effective approach is continuous rigid insulation over studs to reduce thermal transfer. Seal up penetrations at walls and ceilings to eliminate air infiltration.
Some of the givens should be use of ultra-high efficiency heating and cooling systems, laying out an efficient plumbing system – minimize lengths of runs, stack bathrooms, etc.
With the huge improvements in light quality and affordability why would you not use LED and CFL lighting fixtures?
One of the essential elements to our health and quality of life is the air we breath. Keep it clean. Utilize low or no-VOC finishes, materials and avoid PVC and plastics with hazardous additives. Filter outside air as well as return air. Use heat exchangers on outdoor air supply. Design exhaust air systems to balance with available outdoor air supply. Make sure it’s clean with active radon remediation and CO detection. Another area that most people don’t consider to be associated with air quality is the stuff you track in on your feet. Provide walk-off and/or shoe storage areas at entries.
Look for ways to use less. Use low-flow fixtures and toilets; use double-flush toilets. Consider automatic faucets. Consider a manifold plumbing system and/or hot-water recirculation pumps – to minimize water usage waiting for hot water at fixtures.
Use materials and products from as nearby as possible.
Solar – PV | Solar – hot water | Wind | Geo-thermal
Science House at the Science Museum, designed by the principals at Shelter, however utilizes both PV solar and geo-thermal systems and produces 30% more energy on an annual basis than it uses!
Buildings in the U.S. today account for significant amounts of total water use, emissions, waste output, and electric consumption – see charts below.
Everything we do as designers to reduce water use, emissions, waste output and electric consumption adds up and makes an impact.