Energy Efficient Remodel of a Heritage Home
Synopsis:
- Achieved more than a 50% reduction in the size and cost of the HVAC system by
installing Icynene® rather than fiberglass insulation
- Improved Indoor Air Quality
- Maintained low moisture/humidity levels, despite extreme outdoor levels
- Reduced energy consumption
The Challenge
Built in 1908 and situated within the federally designated historic district of Wilmington, North Carolina, an
abandoned home was acquired for rehabilitation by homeowner, Martyn St. David. Deemed to be in a general
state of disrepair, the building was to be gutted and restored in order to serve as Martyn's residence as well
as her office.This was to be achieved while remaining sensitive to environmental concerns when choosing
building materials.
Moreover, Martyn's allergic reactions to mold and mildew demanded a high-performance insulation and
air barrier that is dedicated to moisture control. By eliminating air leakage,The Icynene Insulation System®
minimizes condensation caused by infiltrating moist/humid air which would otherwise be transported through
the building envelope, invading cool, air-conditioned surfaces. Minimizing the opportunity for condensation
helps prevent mold growth within the walls and ceilings.
The challenge was to convert this previously abandoned house into an Energy Star™-rated home.To earn
the Energy Star™ designation, the home must receive a minimum Home Energy Rating (HERS) of 86, which
translates to at least a 30% increase in energy efficiency versus the Model Energy Code.
The one-story, five-room, 1,104 square foot home was to be converted to 2 bedrooms with a home office.
This made the reduction of airborne sounds a key factor when evaluating insulation alternatives.
The original clapboard structure was designed long before air conditioning was a standard household feature,
so it was built to circulate air throughout the wall system. In balloon frame tradition, all interior wall stud
cavities were open from the crawlspace to the attic, which had vents installed into the gable ends.These gable
vents would provide an avenue of escape for the hot air. By incorporating lots of windows for primary
ventilation, this design provided for a fairly comfortable home in the days of unlocked doors and no security
alarms. However, high humidity levels experienced in North Carolina during the summer months affected
the humidity levels inside the home. During these months, interior humidity levels were equivalent to the
extreme levels that were present outside.
The Solution - Insulate with Icynene®
The need for a Healthier, Quieter, More Energy Efficient® living environment inevitably resulted in the decision
to install The Icynene Insulation System® in this heritage home.This high-performance, soft-expanding foam
insulation was required to tighten the building envelope in order to decrease interior humidity levels, improve
indoor air quality, regulate the attic temperature and incorporate a properly-sized heating and cooling system
to optimize performance and energy efficiency.
The installation included:
- R-20 (5.5 inches) of The Icynene Insulation System® in the roof deck, which allows the attic
temperature to adjust within 10°F of the ambient interior temperature of the house.
- R-13 (3.5 inches) of The Icynene Insulation System® in the walls
- R-20 (5.5 inches) of The Icynene Insulation System® under the floor
- The HVAC system installed was a 10 SEER, one-ton, ductless unit
The Results
As a complete air barrier,The Icynene Insulation System® helps prevent the infiltration of warm, moist air
that can condense and lead to the growth of mold and mildew. By sealing out dust, allergens, odors and
pollutants, Martyn does not have to worry about the detrimental effects caused by poor indoor air quality,
which would otherwise irritate her allergies. She also notices much less dust around the house, which causes
even less disruption to her respiratory condition.
Icynene's philosophy of building tight and ventilating right proved to be a successful technique, according to
the data supplied by the homeowner:
- The house was designated as an Energy Star™ home, exceeding the EPA requirements of HERS 86.
- Total HVAC energy costs for a 52-week period from May 2002 to May 2003 were $343.04, for an
average of $0.94 per day.
- The installation cost of the HVAC system amounted to $1,367. Had the house been insulated with
fiberglass, the HVAC contractor estimated that a 21/2-ton unit would have been required, with the
installed unit costing approximately $3,500. Icynene® saved the homeowner $2,133.
- Humidity readings for the period between May 2002 and October 2002 ran between 44-50%
inside, even when the humidity levels exceeded 90% outside.
- The attic temperature never exceeded 7°F above the ambient temperature of the conditioned living
space.3 The temperature was monitored during the months of August and September 2002, when
the exterior temperatures ran above 92°F for extended periods of time.
With regard to the performance of Icynene® as a method of minimizing the intrusion of airborne sounds,
Martyn attests that the office is not invaded by unwanted noises. As the sidewalk was being replaced near
the home during the summer months of 2002, Martyn's work space was not affected; "Even with the back hoe
operating only 25 feet from where I sit in my office, there was no need to raise my voice in conversation with staff to
compensate for the sounds or vibrations, as they were minimal".
The Icynene® - insulated Heritage Home:
- Created an airtight building envelope to minimize moisture and condensation,
thus helping to prevent mold growth
- Optimized energy efficiency with HVAC rightsizing and lower energy costs
- Decreased and maintained interior humidity levels
- Minimized the intrusion of airborne sounds to create a quieter work and living environment
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