With a conventional 2 x 6 wall, you get a nominal R-19 rating, but the effective R-value is usually only a little over ½ of that due to heat transfer through wood components, voids around the wiring, and real-world conditions.
Our minimum preferred framing system is a 2 x 4 wall with sprayed-in-place cellulose insulation backed with R-7 rigid foam insulation on the outside. The asphalt-impregnated paper facing on conventional fiberglass insulation is extremely flammable and difficult to extinguish once ignited. The cellulose insulation is a recycled product that is treated with borax and boric acid. Another example of green products having unexpected side benefits. Additional benefits are: reduced air infiltration, reduced cleaning, increased the usable area of the house and the overall measured external square footage, controlled insects and mold, and increased fire resistance.
We have also built frame walls with a nominal R-value of up to R-35, which is about what a straw bale wall is but requires much less floor space. This gives an effective R-value close to R-27.
Almost 20% of the heat loss in a conventional building is due to air infiltration under frame walls. About 15% is due to heat loss through the opaque wall areas. Air leakage under the walls is a more important factor than the nominal R-value of the wall, but it requires more research, more attention by the builder, and it is much harder to put in an advertisement.
A typical house with 2 x 6 walls might have 120 less usable square feet than if it were built with our minimum framing system. It would have an appraised value area of 60-120 feet more. At $100 per square foot, that would be an $18,000 to $24,000 difference in your taxed property.
More important are the long-term ownership benefits. As an example, if a $10,000 investment in energy conservation saves $800 the first year and energy costs rise at 10% per year while housing values increase at 8% a year, at the end of the second year the energy savings will be $1,680, while the $10,000 investment will have appreciated to $11,800. After ten years, that $10,000 investment will have appreciated to $52,338. It will have saved $12,750 in energy costs. Also, the initial investment is typically part of a mortgage and may be tax-sheltered.
This does not count intangibles such as protecting the environment, preserving indigenous cultures from exploitation, providing a stronger economy, and having lived in a healthier home. Experience has shown that over time intangibles are often the most valuable and the most profitable. Economy and ecology have the same root word: Oikos, which is Greek for house. What goes around comes around. We pay now or we pay later with interest, and the hidden charges are the ones that hurt the most.
Jim Graham, Las Cruces New Mexico Builder
LEED (Leadership in Energy and Environmental Design) is a globally recognized sustainability achievement symbol. It is the most widely used green building rating system and is available for new construction and remodels. LEED provides parameters for building efficient, healthy buildings with cost-saving methods.
The benefits of LEED Certification include:
- certification requires third party inspection and testing, which provides objective quality assurance above and beyond the mandatory building inspections.
- Reduced energy and water usage
- Lower operating costs
- Less construction waste
- Reduced liability
- More durable buildings
- Supports the local economy
- Greater resale value
- Improved indoor air quality
- New Mexico’s Sustainable Building Tax Credit will return up to $13,000 in tax credits for a residential building that earns LEED Platinum Certification.
- It is becoming easier for individuals with modest incomes to have their homes remodeled or built to green standards.
Don and Beatriz Rudisill reach for the highest level of LEED certification
By Bethany Conway, The Las Cruces Bulletin
Editor’s note: This is the first article in a series following the construction of Las Cruces’ first Leadership in Energy and Environmental Design (LEED) Platinum Certified home. Though owners Don and Beatriz Rudisill will not know whether they achieve this certification until their home is complete, sharing their story will help others on their journey to becoming green.
For Don Rudisill, the story behind his home at 4367 Isleta Court is in many ways similar to that of “the first penguin.”
Reaching for Leadership in Energy and Environmental Design (LEED) Platinum Certification – never before achieved in southern New Mexico – he is a lot like the first penguin that takes the plunge into cold, unfamiliar territory.
“When you watch a film about penguins, most people notice how they bunch up on the edge of the ice. No penguin wants to be the first to jump into the water where unknown dangers may lurk,” Rudisill said, referencing an excerpt from “The Last Lecture” by Randy Pausch. “The same happens with building something new. Many people like the idea of a green home – improved energy efficiency, a healthier home, and improved utilization of the planet’s resources all sound good – but there are many unknowns.”
After two years of intense planning and overcoming many obstacles, Rudisill is blazing a trail for others to follow – a green trail. He will accomplish this with the help of builder Jim Graham of Sun and Earth, who has 30 years of green-building experience.
“It a very ambitious project,” said Miles Dyson, owner of Inspection Connection LC and the only certified Home Energy Rater in Las Cruces. “He has it very well laid out.”
Dyson, southern New Mexico’s go-to guy when it comes to achieving LEED and Build Green New Mexico (BGNM) certification, will inspect the home throughout the entire process. Credit categories for LEED homes include Sustainable Sights, Locations and Linkages, Indoor Environmental Quality, Water Efficiency, Materials and Resources, Awareness and Education, and Energy and Atmosphere.
The trail began when Don and Beatriz Rudisill sat down to create the home’s footprint. The unusual floor plan is partially the result of the couple trying to meet the LEED requirements for passive-solar design. According to the LEED program, the maximum conditioned square footage for a three-bedroom house should be 1,900 square feet. By going above this amount, the couple loses points. By going below it, they gain points.
“We are trying to stay under 1,690 square feet, which gives us three points (toward LEED Platinum Certification),” he said. By creating a storage closet for seasonal clothing near the master bedroom and a sunroom on the southeast side of the house – two areas that will not be heated or air-conditioned – they will be able to add extra space not counted toward their conditioned square footage.
“This is going to generate a lot of solar heat in the winter,” Rudisill said of the sunroom. “During the summer months, we intend just to leave the windows open, and this will be a bonus room. Jim (Graham) is going to put a fan in here because in the winter it will produce surplus heat that we will be able to blow into the house.” Solar hot water panels hidden behind the parapet over the garage roof will provide additional heat.
Another way they were able to gain points and energy efficiency was by keeping all of the hot water within a 20-foot radius. For this reason, the kitchen and bathrooms are all “clustered within the center of the house.”
“If you look at the plans, we had this 20-foot circle drawn, and that created another requirement for the floor plan,” Rudisill said.
When it came to the slab itself, they used 30 percent fly ash – a waste product from coal after it has been burned in a boiler.
Next on the list was the framing, which was done using finger-jointed lumber. “You take scraps that are too small to be used and make a usable piece out of it,” Rudisill said.
When it came to placing the Marvin windows with ULTREX fiberglass frames, Rudisill also had to be very particular in order to gain LEED points. “I put a lot of time into trying to capture the views because we are given glass budgets. You have to keep the glass within a certain percentage,” he said.
One of the most important attributes of the home are the Structured Insulated Panels manufactured by KC Panels of Animas, N.M, which will make up its 4-inch thick walls. Graham said this is the first time he has used the insulated panels. The thermal resistance, or R-value of the panels, is so high they perform almost twice as well as standard 6-inch walls and result in more than 30 square feet of space being shifted from the walls to the available living space. They are held together by polyurethane foam.
“The foam creates a complete seal around the building,” Rudisill said. “So again, through using this one product, we are saving space and improving energy efficiency. The air-tight seal contributes to improved indoor air quality, and the foam has a class-one fire rating, improving the safety of the home.”
From 10 a.m. to 1 p.m. Saturday, April 18, and 1 to 4 p.m. Sunday, April 19, during the Guild of the Las Cruces Symphony Association’s green home tour, titled The Greening of Las Cruces, residents of Las Cruces will get a chance to visit the construction site and view these panels up close.
“I have an interest in trying to get the information out there about what really goes into a well-built house,” said Rudisill, adding that by educating the public he is actually gaining more points toward the home’s certification.
Though the Rudisills are hopeful they will reach their goal, they won’t know if LEED Platinum Certification will be achieved until the project is complete.
“Being the first to attempt the Platinum level means that we have to be the first in the area to earn certain points. One of the areas that we are earning points is by working as an integrated design team. We have been working very hard as a team with Miles, Jim, and several subcontractors all putting their heads together to help ensure that the rating is achieved.”
Assuming they achieve the platinum rating, the Rudisills will receive $9.50 per square foot in tax credits – close to $15,000.