Best Practices for Homebuilders and Energy Codes

Home Buyers Demand Energy Efficiency and Comfort

Energy codes put dollars in consumers’ pockets and protect consumers into the future by reducing utility bills, increasing their buying power, and improving home comfort. Energy savings derived from low utility bills increase the buying power of citizens. Dollars not spent on energy are available for better, more affordable housing, particularly for those from lower income brackets who tend to get stuck in aging, inefficient rental housing. Homebuyers can access affordable mortgage products, including energy efficient mortgages that enable either lower payments, or payments that remain the same but allow greater home buying power.

Fewer Customer Callbacks

Builders want to reduce callbacks, which decrease the profitability of their business. Following the applicable IECC requirements for duct construction, sealing and insulation can reduce operating costs, increase customer comfort, and eliminate callbacks from those areas. The requirements also improve indoor air quality and reduce moisture problems associated with poor duct construction, a major source of callbacks for builders.

Reduced Liability

Compliance with the air sealing requirements of the IECC can also help reduce liability. These requirements provide guidance for improving a home’s resistance to air leakages and moisture problems, and for lowering mold, mildew and rot problems often caused by indiscriminate air leakage and moisture movement into the building envelope.

Builder-friendly training

Implementing current national model energy codes and standards enable designers, builders, and code officials to participate in training opportunities and use implementation materials developed by the Department of Energy and other national entities. The builder-friendly REScheck system for residential buildings is the system of choice for many builders, including those in New York, Minnesota, Massachusetts, Indiana, Ohio, and dozens of other states.

Increased Attention from Lenders

An energy efficient statewide code is more likely to attract national lenders, such as Fannie Mae, to design financial products geared to raising the debt/income ratio, thus enabling more working families to afford their first homes. Compliance with a statewide building code that includes current nationally recognized energy standards may enable more homes to qualify for FHA, VA, or RHS financing, since federal mortgages require that new homes be built to comply with the national model codes.

You can lead the way

Builders can take a leadership role in this nation’s fight against high energy prices and climate change. In 2009, the National Association of Homebuilders (NAHB) estimated that barely half of the homes needed by 2030 had been built. The potential energy and cost saving in the remaining years before 2030 are still huge.

Best Practices

Insulate Properly – Make sure you use the IECC required insulation levels at a minimum, and more insulation as cost-effectiveness allows. Most importantly, make sure that insulation is installed in accordance with the manufacturer’s specifications. Insulation with gaps and voids will not perform properly, causing energy and comfort problems later on. Try combination systems that utilize high performance foam and loose-fill insulation, taking advantage of the best properties of both. Create air barriers at soffits and other vents and behind kneewalls to prevent air from reducing insulation effectiveness.

Infiltration Control – This is one of the most misunderstood code requirements. Proper air sealing of the building envelope is one of the two biggest energy savings practices, and it also helps prevent a myriad of other problems. Air leakage through the building enclosure can cause severe degradation of insulation loose-fill and batts. It can also carry moisture to that insulation, further degrading it and potentially causing mold and rot issues. Thoroughly seal all of the “big holes” like kneewall areas, chimney chases, attic hatches, recessed lighting, and common walls in multifamily units. Think about creating an “air barrier” as one of the primary enclosure design goals.

Duct Construction/Sealing – Another misunderstood code requirement: duct installation, sealing, and design. Ducts are often built improperly, located in unconditioned spaces, unsealed and generally dealt with poorly. It is essential to air seal, with mastic, all joints in all kinds of ducts and air handling distribution elements. Leaky ducts can account for a third of a homes heat loss, resulting in comfort issues and even home depressurization issues that can cause appliance backdrafting (and CO poisoning). Be sure to seal everything in the duct system from the air handler out. Use only UL-181A/B rated Mastic or tapes. Size your duct system properly using ACCA Manual D or equivalent, and by all means, try to get the designer to design space inside the building enclosure for the ducts. You’ll save money by not having to insulate them, and have a better, more callback free system that conditions the home better.

HVAC Sizing Calculations – These calculations are required by code but often done incorrectly. The IECC and the IRC require it, and good
design practice encourages it; however, too often HVAC systems are poorly sized for the application. Often times, rules of thumb are used, leading to oversized equipment and distribution systems. Oversized equipment leads to higher first costs, poor comfort and excessive energy use, and can often lead to poor dehumidification in the case of central A/C systems, with all the related problems that can stem from excessive humidity. The codes require ACCA Manual J or equivalent for systems, and ductwork should be sized using Manual D for best results.

Additional Resources