HERS

HERS

New Construction

HERS inspections during construction (and therefore CF-1R registration with a HERS registry prior to plan check) are mandatory for the following components in all new residential construction in all climate zones:

  • Indoor Air Quality exhaust fans.

  • Duct sealing (< 5% leakage, including ducts within conditioned space).

  • Duct location (if credit is taken for ducts in conditioned space).

  • New A/C units. Air handlers must maintain > 350 CFM/ton of cooling, and  Fan watt draw must be < 0.58 watts/CFM.

HERS verification is also required for certain optional components, such as Quality Insulation Installation (QII).

  • QII is an excellent compliance credit. In fact, NOT showing QII is an automatic 20% compliance penalty under the Performance Approach. 

  • Insulation is considered by many to be one of the least-important aspects of a building. Consequently it’s bid cheaply, installed quickly and poorly and accounts for some of the largest thermal transmission gains or losses in the building. See Newsletter #3.2, Holey Insulation.

  • QII results in a better end-product, but requires budgeting for multiple site visits by a HERS rater to correct poor installations.

  • QII also requires a clear understanding by the general and drywall contractors that no insulation is to be covered (especially behind tubs and showers) until the HERS rater has signed off.

When HERS is required on an existing residence—before calculations

Beginning with the 2013 Energy Standards, for additions where we want compliance credits for upgrading certain components on the existing house, we must have a HERS rater VERIFY the existing conditions prior to the calculations being done. This is separate from the work the HERS rater performs DURING construction. Examples:

  • Upgrading existing roof or wall insulation (or lack thereof).

  • Upgrading Tank-type water heater to tankless.

  • Replacing existing ducting or HVAC units.

  • Replacing existing glazing with high efficiency units.

When HERS is required during construction on an addition or alteration

Note: For additions or alterations involving the following, HERS inspection during construction (and therefore CF-1R registration with a HERS registry prior to plan check) are also required:

  • New or replacement A/C units: Air handlers must maintain > 350 CFM/ton of cooling, and  Fan watt draw must be < 0.58 watts/CFM.

  • More than 40 lineal feet of new ducting is added to or replaced in an existing duct system. Entire duct system is leak-tested to the extent possible, with a target of     < 15% leakage.

The Installing Contractor and Your Plans

Often the Installing contractor for HVAC, water heating (and sometimes glazing) uses equipment efficiencies other than what was used for compliance.  If they use something less efficient and the building inspector sees it, you have a choice.

  • You can tear out the equipment and put in something to match or exceed the efficiencies that were used for compliance

  • Re-run the energy calculations. There will be a fee for a rerun of the calculations and depending on which components have already been installed in the building, there may be no way to obtain compliance without removing some of those components.

I can’t recommend strongly enough that you ensure that the installing contractor uses the same or better efficiencies than were used for compliance.

Jobsite Changes

Adding glazing during construction will require a re-run.  Relocating glazing during construction may require a re-run.  Walking through the building when it’s being framed sometimes allows the Owner to see where they might want additional glazing. If the HVAC and water heating have already been installed, we can’t easily upgrade them to compensate for the glazing-related compliance penalty. Glazing changes during construction are best investigated before mechanical equipment is even purchased;  It’s best if the Owner understands that this can save them considerable construction money on a seemingly innocent change order.