RESIDENTIAL BUILDINGS, ADDITIONS AND ALTERATIONS

2008 Residential Energy Standards

All new low-rise residential construction and additions (i.e., new or newly conditioned space) must meet the overall energy efficiency requirements of the Residential Standards. Alterations that do not add conditioned space must meet all applicable mandatory measures. Alterations with new or replacement glazing must either meet prescriptive U-factors and SHGCs, or comply with the Residential Standards using performance method calculations. Alterations where more than 50 square feet of new fenestration is added to existing buildings and where the total proposed fenestration area is more than 20% of the conditioned floor area must comply with the performance method.

• We will work with you on single family homes, duplexes and multi-family buildings; on any size residential addition, including legalizing a space not previously permitted; and on alterations in which new glazing does not meet the standard minimum fenestration values.
• We will discuss with you the specific trade-offs between insulation, glazing, shading, HVAC and water heater efficiencies, and the inclusion of special HERS measures to achieve energy compliance.
• We will perform an Existing+Addition+Alteration calculation when an addition or alteration will not meet the code by itself, allowing improvements to the existing house to count as credits toward, for example, an addition with large glass areas.

The 2008 Residential Standards include several changes from the 2005 energy code:

• Prescriptive Package D U-factors for windows and other fenestration have been tightened to 0.40 in all climate zones, while prescriptive SHGC (shading) values have been tightened in some climate zones. U=0.40 corresponds to an NFRC-rated wood or vinyl frame window with Low E glazing. Note that the requirements of Package D are used to set the energy budgets for performance method compliance. Minimum mechanical ventilation rates to meet indoor air quality are now required in new construction, including additions larger than 1000 square feet.
• Greater weighting of electricity use during peak hours (i.e., increasing Time Dependent Valuation energy credits and penalties during summer afternoons). Prescriptive HERS duct testing is now required in all climate zones with no alternatives, and there have been some revisions to other HERS measures available for energy credits.
• New online registration required for all projects with HERS measures starting October 1, 2010.
• Revisions to the Certificate of Compliance (CF-1R) form to facilitate better field inspection.
• A few changes to indoor and outdoor mandatory lighting requirements.