Multifamily Duct Sealing and Duct Insulation

Ensure the home qualifies:

• Must be an existing property, not new construction
• Work completed must comply with all building codes and standards

Requirements for both measures:

• Work must be completed by a Program-Eligible or Qualifed HVAC Contractor listed on the Program-Eligible HVAC Contractors List. Please review our tips for hiring a contractor
• Work must be done in accordance with the specifications outlined in the Idaho Technical Specifications Manual
• Ducts must be located in an unconditioned spacespaced such as any space outside of the thermal envelope of the biulding that is not intentionally heated for occupancy
• Must have a minimum of 10 linear feet of exposed ductwork. All exposed ductwork must be sealed and insulated (ductwork only, not venting)
• Property must have an electric heating system serving 80 percent the home's conditioned living space
• Duct sealing must reduce duct leakage to outside by 50 percent with a 100 CFM (Cubic Feet per Miniute) minimum reduction
• Duct insulation must be installed after ducts are sealed
• All physically accessible ducts located in codintioned living spaces must be insulated

Additional requirements for duct sealing and duct insulation:

• Ductwork must be insulated to a minimum of R-8
• Pre-existing duct insulation levels may not exceed R-2

Additional requirements for duct sealing (stand-alone):

• Pre-existing insulation must be R-2 or greater

​Additional program requirements:

• Duct sealing and duct insulation services can be performed by multiple trade allies and must be performed at the same time to qualify
• Incentive available on existing duct work only and must be located in an existing property
• Newly installed ductwork does not qualify for an incentive
• Incentives are limited to one duct sealing incentive per duct system for the lifetime of the property
• Incentive amount cannot exceed the total cost of the project
• All required documentation must be postmarked within 90 days of the work completed date

Required documentation:

• Contact the program to schedule a pre-inspection and to get the required application documents at hesmultifamily@rockymountainpower.net
• Itemized receipt or contractor invoice
• Third Party Payment Addendum for applicants who would like to forward payment to a third party not listed on the utility account
• IRS W-9 Form, if applicable*

*Applicable only to businesses and non-individual customers, including landlords, applying for incentives

Conditioned vs. unconditioned space - clarification notes

• For the most part, basements are conditioned spaces. Basements are not usually thermally isolated from the main living area and contain space conditioning ducts. Basements are also used for storage and frequently contain laundry facilities and other living spaces. Ducts serving unfinished basements are not always equipped with dedicated supply registers, although single registers at plenums are not unusual.

• An unconditioned basement would have these properties: Thermally isolated from the main floor by insulation in the floor. Insulated, weather-stripped door (if above floor plane) and insulated stairwell walls where thermal plane penetrates floor, air sealed (caulked, foamed penetrations) wiring plumbing, sealed duct penetrations and sealed, insulated ducts. No supply registers.

• While a crawl space is unconditioned space, the floor must be insulated prior to or at the same time ducts are sealed and insulated to thermally isolate the crawlspace. Failure to do this will increase the heating load of the home and potentially cause comfort issues.