Hot green building trends Part 2
As building codes become more energy-efficiency focused and water conservation takes on a larger role, builders and homeowners seek new products and practices that satisfy the new standards.
Here’s an overview of green building technology and techniques that will help meet consumer demand for high-performance homes.
Sealing the thermal envelope
Recent research by Building Science Corporation showed that air sealing is at least as important as the R-value of the insulation in a building envelope. In 2013 Building Science Corp. issued “The Thermal Metric Summary Report,” the result of a multi-year research project that compared the performance of various types of insulation, including fiber glass, cellulose, spray foam and extruded polystyrene.
The study showed that if the wall assembly was effectively sealed from the inside and outside so there was virtually no air movement, the walls performed the same regardless of the insulation type. If there was air movement through the wall, then all types of insulation experienced a loss of thermal performance.
Air sealing can be accomplished in a variety of ways: through joint sealing with tape, exterior and interior wraps, and application of spray foam insulation.
Spray foam insulation, both closed-cell and open-cell varieties, offers a number of benefits for building professionals and homeowners looking for a cost-effective air sealing and insulation strategy.
With the growing emphasis on air sealing, products such as Huber Engineered Woods’ Zip System R Sheathing have become integral to a high-performance home design. The Zip System is an oriented-strand board (OSB) coated with an air barrier and 1 inch of insulation to reduce thermal bridging.
The Zip System was a major component in the Proud Green Home at Serenbe, and one of the reasons the home was able to achieve a minus 2 HERS rating
Read more about insulation.
From advanced framing techniques to SIPs to ICFs, builders have never had more options in choosing a high-performance wall system for energy-efficiency and durability.
ICFs are becoming popular for both their energy performance as well as their durability in storm zones of the country. In fact, some builders have planned wholedevelopments based on homes with ICF construction to achieve the highest level of energy performance.
The Proud Green Home at Serenbe employed advanced framing techniques, spray foam insulation and the Huber Zip system to achieve performance that earned the Platinum level of EarthCraft certification. It also earned recognition as the EarthCraft House Project of the Year.
Read more about wall systems.
Water conserving toilets
Toilets made before 1994 toilets used about 3.5 gallons per flush. Now many toilets on the market use only 1.28 gallons per flush.
Kohler estimates the 1.28-gpf toilets will save homeowners on average 16,500 gallons per year, or about 63 percent of the water used compared to the old-style toilets.
Switching to a high-efficiency toilet will cut back drastically on water usage. Conversion to 1.6-gallons-per-flush toilets will save 14,000 gallons. And dual-flush toilets will cut water use to about 10,000 gallons — an annual savings of more than 17,000 gallons.
High-efficiency toilets fit into these categories:
- Single-flush, at 1.6 gallons per flush (gpf)
- Dual-flush, with 1.6 gpf/0.8 gpf
- Pressure-assist, with 1 gpf
To qualify for the EPA WaterSense label, toilets must flush on average with 20 percent less water than 1.6 gpf.
Single-flush toilets using 1.6 gpf are required by code in most new home construction and bathroom remodeling jobs. They require, as the name implies, a single flush for solid and liquid waste.
If you’re looking for another water-saving toilet option, Kohler, along with many other manufacturers, offers dual-flush technology. The toilet is equipped with two buttons to allow users to select one of two water levels with each flush. Kohler’s line of Persuade toilets uses 1.6 gallons or 0.8 gallons per flush, allowing it to qualify for the WaterSense label as well. The user chooses how much water to employ in flushing away light or bulk waste.
Read more about water-saving devices.
Geothermal heating and cooling
Geothermal heat pumps give homeowners and companies the ability to reduce their carbon footprint while taking advantage of the most energy efficient heating and cooling system on the market.
According to a report by Pike Research, geothermal heat pump shipments in the United States are projected to see growth from just fewer than 150,000 in 2011 to more than 326,000 units by 2017.
A geothermal heat pump is so efficient because it uses the constant 55 degree temperatures just a few feet underground to exchange heat from the home. The geothermal system can heat and cool homes and buildings of all shapes and sizes. A homeowner using a geothermal heat pump can expect efficiencies that are 400 to 500 percent higher than those of the most efficient traditional heating and cooling system.
Read more about geothermal heating and cooling.
Residential solar power continues to gain ground as the third quarter of 2013 marked the largest quarter ever for residential photovoltaic (PV) installation, according to a new study from GTM Research and the Solar Energy Industries Association (SEIA).
The information comes from their just-released study U.S. Solar Market Insight: 3rd Quarter 2013.
Residential PV installations grew 45 percent year-over-year to 186 MW, a record. This increase was driven by increasingly attractive economics for solar power, and fair net metering policies.
More and more homebuilders offer solar power as standard or optional equipment on their homes.
A study in Denver found that solar photovoltaic systems increase market value and almost always decrease marketing time of single-family homes, according to a study by the Appraisal Institute.
And more efficient solar modules are on the way. A new mass-produced solar module reached 35.5 percent efficiency in tests, compared to 15 to 20 percent for modules on the market today.
Read more about solar power.
Topics: Building Green, Cost of Ownership, Exteriors, Foundations, Geothermal Heating & Cooling, Insulated Concrete Forms - ICF, Insulation, Photovoltaic / Solar Panels, Plumbing & Fixtures, Proud Green Home at Serenbe, Sinks & Toilets, Solar Power, Sustainability Trends & Statistics, Sustainable Products, Water Saving Devices
Gary Wollenhaupt is an experienced writer and editor, with a background as a daily newspaper reporter as well as corporate and agency public relations and marketing. He is constantly looking for affordable green upgrades to make to his home in eastern Kentucky.www