Transformation of a 1950s Ranch into an Earth Craft Home
Synopis:
- Reduced air infiltration by 43%
- Achieved Home Energy Rating (HERS) of 87
- Decreased heating and cooling costs, despite the 47% increase in living space
The Challenge - Optimizing Energy Performance While Preserving Original Architectural Details
Converting this 1950's era ranch into a two-story residence is a prime example of how a home can be transformed while retaining
much of the original structure and incorporating new building technologies to meet EarthCraft House™ standards for a healthy,
cost-effective home. Following EarthCraft House™ guidelines, this project was completed by SawHorse, Inc., a prominent design/
build firm in Atlanta, and Glenn Cartledge, homeowner and architect.
EarthCraft House™, a program of the Greater Atlanta Home
Builders Association and Southface Energy Institute, is committed to assisting builders to construct healthy, comfortable, affordable
homes that reduce energy and water bills while utilizing sustainable building products.
Located in Atlanta, GA, the renovation of the Cartledge residence included the addition of a second level, increasing the living space
from 3,338 sq. ft. to 4,921 sq. ft. An additional bedroom was also created for a total of 4 bedrooms. The Cartledges also wanted
more natural light to penetrate the home, which resulted in a 255% increase in window area (from 250 sq. ft. to 887 sq. ft.).
For
increased energy efficiency, the A/C system increased from 10 SEER to 12 SEER, while the furnace increased from 78.5 AFUE to
95.5 AFUE. Return and supply ducts also increased from 114 sq. ft. to 305 sq. ft. and 229 sq. ft. to 380 sq. ft., respectively. Other
redesign elements included major interior renovations to the original first floor and basement levels. The first floor was gutted to
the studs and fiberglass insulation was removed from the wall cavities.
Despite the increase in living space and conditioned area, the EarthCraft House™ objective was to increase energy efficiency by
creating a well-insulated thermal envelope that would deliver optimal airtightness for a Healthier, Quieter, More Energy Efficient®
living environment.
The Solution - Insulate with Icynene®
All homes allow some amount of air infiltration through gaps, holes and penetrations in the building envelope. Older houses,
however, tend to be very leaky.The renovation guidelines established by EarthCraft House™ explain that an older home typically
replaces all of its air once each hour. However, it is recommended that air changes per hour do not exceed approximately 1/3 of
the air in the home.The Icynene Insulation System® is a complete insulation and air barrier that was specified to help the builder
achieve this target. Icynene® controls random air leakage to reduce the amount of air changes per hour in order to decrease heating
and cooling loads on the HVAC system. Icynene® allows the home to maintain a constant, comfortable temperature and humidity
level, while using less energy.
The key is to eliminate as many air leaks as possible and then introduce controlled ventilation. By minimizing random air leakage
and controlling airflow, Icynene® allows for rightsizing of HVAC equipment to significantly reduce heating and cooling costs and
maintain controlled humidity levels.
In order to incorporate a properly sized heating and cooling system, the design and construction of the heritage home included the
following repairs and upgrades:
- R-13 of Icynene® insulation and air barrier system replaced R-13 fiberglass insulation in the first floor exterior walls.
- R-13 fiberglass insulation removed from old attic assembly.
- R-21 of Icynene® insulation and air barrier system applied to new vaulted ceiling.
- Window area increased from 250 sq. ft. to 887 sq. ft.
An efficient building envelope, thermal comfort and a dry, healthy living environment are all integral components of sustainable
building and design. As part of the remodel of this 1950's traditional home, SawHorse, Inc. decided that the Icynene® application
was the best option for this project in order to ensure that all of these components were incorporated without sacrificing the
integrity of the ranch's original architectural details.
"After exploring various insulation systems for this project, we determined that taking advantage of Icynene®'s combined
insulation and air infiltration control properties provided us with significant cost and performance advantages over conventional
insulations. Other insulation options required separate air-sealing methods to meet the performance requirements for this house."
- Carl Seville,Vice President of SawHorse, Inc.
The Results
Fulfilling the criteria established by EarthCraft House™, the Icynene®-insulated custom home demonstrates the benefits of employing
advanced building technologies and construction practices for increased energy efficiency and superior indoor air quality.
Icynene® also allows for new design strategies, according to Mr. Cartledge, "By its nature, Icynene® requires no ventilation space from
soffit to ridge, which increases design freedom for both the exterior and interior of the house. Icynene® is intended to fill all of the gaps and
crevices, thus eliminating the need to leave a path for air ventilation within the rafters."
Icynene® addresses moisture concerns by minimizing air movement through the building envelope, which accounts for 99% of
moisture migration and subsequent mold and mildew problems.
Icynene® was ideal for this remodel project. It met the expectations of Mr. Cartledge, as well as those of EarthCraft House™.
The following results were achieved:
- Air infiltration rate reduced from 0.65 ACH to 0.37 ACH @ natural pressure, meeting the recommendation of
1/3 air changes per hour.
- Decreased heating and cooling consumption per square foot by 12% and 54%, respectively, despite the increase
in conditioned space.
- HERS rating of 87 achieved - 10 points above the home's original HERS rating before renovation (HERS 77).
- Remodeled home exceeded the qualifications for the ENERGY STAR® label (the home is 5% more efficient than
the ENERGY STAR® requirement).
The high-performance insulation solutions offered by The Icynene Insulation System® allowed SawHorse, Inc. to achieve optimal
airtightness levels and maximum energy efficiency. In one step, the spray foam insulation and air barrier sealed all gaps and crevices
that compromised airtightness.
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