A cure for the energy bill blues?
SIPs prove to be a smart choice for Upstate New York couple
With spring on the horizon, Charles and Becky F. just can’t get over how little they spent on heating costs this past winter.
The retired couple moved into their 1,408 sq. ft. bungalow in December and since then have only gone through two face cords of wood to heat their home out in the Upstate New York country.
That’s most of the winter with just a single wood stove and about $125 in firewood.
The secret to their low heating bills lies in what’s inside the exterior walls, floors, ceilings and frost walls of their home. What’s known as the “building envelope” of the house is constructed entirely of Structural Insulated Panels (SIPs), an innovative product that replaces two-by lumber framing and fiberglass batt insulation entirely.
A SIP is a large panel consisting of a solid foam insulation – expanded polystyrene (EPS) – laminated between two sheets of oriented strand board (OSB). Each panel is 4-feet wide and comes in varying heights, most commonly 8’, 9’ and 10’.
They are assembled together systematically, one at a time on the job site, creating the structural frame of the house, while delivering a solid, unbroken layer of insulation.
Charles and Becky learned about the merits of SIPs from their builder, whom they considered a most trustworthy source: their son, Paul of C+P Mill Works, has been building almost exclusively with SIPs for three years.
“In 20 years, all homes will be built with SIPs,” says Paul. “They provide superior structural strength and are incredibly energy efficient.”
The fact that Charles and Becky typically started a fire in their wood stove only every other day throughout the winter attests to the energy efficiency of SIPs.
And although his parents have yet to spend the summer in their new home, Paul predicts equally delightful air conditioning costs. His crew was finishing the inside of the home in August, running a puny 5,000 btu window AC unit – normally rated for a single 150 sq. ft. room – that kept the entire house at a comfortable temperature.
This is no surprise to Jeff Taraba, Vice President of Thermapan Structural Insulated Panels, who manufactures SIPs for builders throughout the Great Lake States and Canada.
“The feedback we regularly get from homeowners who have chosen our product is incredible,” says Taraba. “Our customers often report that their heating and cooling energy bills are up to 70% lower than a conventionally-built home of the same size.”
According to Taraba, one of the main differences between a SIP-built home and a stud-framed home is the air tightness of the insulation. “Real-time energy loss studies consistently show that fiberglass insulation performs well below its rated R-value in cold temperatures,” says Taraba. “That’s because fiberglass is an open-cell insulation, which allows air to infiltrate.”
The EPS core of a SIP, in contrast, is a closed-cell insulation. Unlike fiberglass, it is rigid, cannot be compressed and simply does not allow air to infiltrate whatsoever.
As a result, says Taraba, you just can’t compare fiberglass insulation with EPS insulation. “R-values are designed in a laboratory setting where air infiltration is taken out of the equation,” he points out. “But your monthly energy bill certainly doesn’t ignore the impact of air infiltration!”
Due to differentials in indoor and outdoor air pressures, air inevitably infiltrates open-cell fiberglass insulation installed in the average home, reducing its real-time (true) value. Yet a 6.5” thick SIP with an R-value of R-29 will perform at a real-time rating of R-29, because its closed-cell EPS insulation isn’t subject to air infiltration.
As for the Paul and Becky, they are sold on the science of SIPs. “Everyone complains about energy costs going up and up nowadays,” says Charles. “We’ve completely bucked the trend with our new home, and our friends are amazed when they hear how much we are saving because of SIPs.”