Single Family / Duplex Projects
Many of the permits for smaller heating systems are available at the Over-the-Counter (OTC) area of DPD's Applicant Service Center (location & hours). You will also need the Heating Equipment Sizing Form, available on our Over-the-Counter forms website or in the ASC.

Triplex and Larger Projects
Work that qualifies for an STFI Commercial permit must meet the following specifications:

  • All work values are less than $15,000
  • Ductwork revisions and additions to existing duct systems. Includes registers, diffusers, grille vents, and up to 2 VAV boxes (fan boxes/VAV boxes without new strip heat).
  • Replacement of equipment in kind, e.g., same fuel type, maximum total of 4 ton/48,000 BTU, weighing less than 500 lbs., within the building interior. NOTE: Replacement in kind of exterior units is only allowed using existing penetrations.
  • New cooling-only units located within the building interior and serving only computer, printing, and refrigeration rooms. Equipment is limited to 4 tons/ 48,000 BTU total and a maximum equipment weight of 500 lbs. Qualifying work is limited to installation of one unit only for each computer/equipment room per application. Heat pumps and units with heating capacity are not allowed.
  • Replacement in kind of unit heaters
  • New unit heaters (requires Heating Equipment Sizing Form)
  • Installation of bathroom exhaust fans on existing commercial systems

Work that qualifies for an STFI Multifamily Residential permit includes:

  • Residential bathroom, kitchen, dryer, laundry room or closet exhaust fans (for type III, IV, or V structures with individual unit venting systems). Each exhaust must terminate at the exterior wall of structure. (Project value may exceed $15,000.)
  • Furnaces and heat pumps in buildings with no more than four units that have systems completely contained within each unit. A separate permit is required for each unit.

It is important to note that the STFI Mechanical permit process is limited in scope and not available for projects that involve any work in shoreline and/or historical districts, or that affect the exterior of the building (other than replacement of certain existing equipment as noted below). See CAM 414, STFI Mechanical Permits for Commercial and Multifamily Residential, for more requirements.

All mechanical projects requiring plan review must still be applied for at the ASC Information Desk. For more information on mechanical and energy projects requiring plan review, see CAM 415, Applicant Responsibilities and Plan Requirements for Mechanical Permits.

Be Prepared
Be prepared before you come in! Download the permit application forms online from our Over-the-Counter forms website.