The following is a guest post by our good friend Miles Dyson of Inspection Connection. Miles is Las Cruces, New Mexico’s foremost expert in home inspection, energy rating, and green certification.
New technique adds flexibility, reduces air infiltration
As I evaluate new Las Cruces, New Mexico homes in the process of qualifying for green certification, I see a recurring theme – increasing use of spray foam insulation (SFI).
A handful of respected area home builders have begun to incorporate spray foam in key building envelope installations for increased energy efficiency and comfort. Pat Bellestri and Soledad Canyon Earth Builders have relied on spray foam to cap off their iconic rammed-earth projects for several years – including the first LEED-certified home our area.
Kyle Schueller at Schueller Homes and Gary Rogers at Planet Development each have adopted hybrid spray foam and dense pack fiberglass insulation strategies for their current respective Build Green New Mexico (BGNM) and National Association of Home Builders Green (NAHB Green) certified projects.
David Coyle of Coyle Builders has augmented super strong and efficient Insulated Concrete Form wall construction in his BGNM/NAHB Green homes with spray foam applied to the underside of roof decking. The most recent green certified homes of JB Stearns of Stearns Custom Homes include two types of spray foam.
High R-value closed cell foam is installed at the underside of the roof deck. Open cell foam completes an engineered and resource efficient wall framing system.
Increased utilization and interest in SFI has been facilitated by local insulation contractors who work to bring down the cost of the product while educating builders on its benefits.
Spray foam specialists in the area include Rob Tollen at Air Tight – New Era Spray Foam and Ernesto Rubio, the local rep for the soy-based Demilec spray foam product. Established local insulation contractors like Ontiveros and Gale Insulation now offer spray foam products in addition to their traditional insulation product line.
Spray foam insulates well, but the key to its often superior performance is that it provides an effective air barrier. SFI traps air in place in the insulation material and prevents air movement through wall, floor and ceiling assemblies. Homes with SFI incorporated in the building envelope have less air infiltration from the exterior.
I have tested SFI homes that have less air leakage for the entire home than commonly found in just the ductwork of most existing homes. This is important since minimizing air exchange to the exterior is one the best ways to improve efficiency in a home – in other words – keep the fridge door shut!
Most traditional insulation is porous or includes gaps and penetrations that let air move through the home’s envelope.
Properly installed foam insulation systems provide continuous coverage that seals small gaps and openings to let the home envelope perform like a sealed Igloo cooler to hold in conditioned air and comfort.
SFI binds to house wall and ceiling framing and greatly increases the strength of those components. Researchers in Florida found that wood frame home ceiling/attic assemblies incorporating SFI resist wind uplift three times better than assemblies that were nailed only. This binding strength and rigidity allows builders to use less wood in wall assemblies while maintaining structural integrity.
SFI walls and ceilings allow greater flexibility in the design of energy-efficient homes. A key goal for green homes is to limit heating and air conditioning duct leakage and duct expo sure to ambient temperatures. SFI offers a simple solution to create a sealed or non-vented attic space. This basically means that the insulation is installed at the bottom of the roof deck rather than on top of the dry-wall ceiling.
All components installed in the attic – especially the duct work – are now on the interior of the home building envelope. Since ductwork installed in vented attics or crawlspaces typically demand 25 percent or more of the total heating and cooling load in the home, efficiency is greatly improved when ducts are brought in to the “conditioned space.” SFI installed in this manner requires no changes to the design or layout of a home to get this improved duct efficiency benefit.
Upfront installation cost for SFI is typically more than for fiberglass or cellulose even though prices continue to decrease. Benefits in reduced utility costs, durability, design flexibility, increased home value and better comfort payback over the life of the home.
For more information on green and efficient homes, visit my website www.icenergyrate.com
Miles Dyson is the owner of Inspection Connection LC – Professional Home Energy Rating and Home Inspection Services in Mesilla Park and can be reached at 202-2457. Dyson is a RESNET certified Home Energy Rater and ASHI certified Home Inspector.
Contact Picacho Mountain today at 575-523-2500 for more information on building your energy-efficient, green home in Las Cruces, New Mexico. Custom Estate Homes, Patio Homes, Town Homes, and Neighborhood Retail.
