Washington, DC HVAC permit requirements

2017 District of Columbia Residential Code = 2015 IRC as amended by the Residential Code Supplement of 2017 (12-B DCMR), effective May 29, 2020. Still the edition in force; DOB's code update to newer ICC editions is in rulemaking (not yet proposed).

2017 District of Columbia Energy Conservation Code, Residential Provisions = 2015 IECC as amended by 12-I DCMR (effective May 29, 2020; R405 replaced 7/30/2021 by an 'Additional Efficiency Package'). DC amends IRC Chapter 11 out: 'N1101.1 General. Buildings regulated by this code shall comply with the Energy Conservation Code-Residential Provisions.' DC R301.1: DC, VA and MD 'are located in Climate Zone 4A'.

DC amended R403.7 (12-I DCMR, Mandatory): 'Heating and cooling equipment shall be sized in accordance with ACCA Manual S based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies.' Exceptions: (1) multistage or VRF cooling equipment; (2) new heating and/or cooling equipment of 1.5 tons or less; (3) ductwork extended from existing equipment into an addition; (4) 'replacement in kind of an existing system, as long as the BTU's of the new system are equivalent or smaller ... and the building thermal envelope is not being altered.' IRC 2015 M1401.3 kept without amendment: 12-B DCMR amends no Chapter 14 sections (its chapter list is B1, B2, B3, B9, B11, B12, B15, B16, B24-B26, B29, B30, B34, B44 plus appendices).

12-B DCMR strikes and replaces only IRC M1601.1.1 (above-ground duct materials). IRC 2015 M1601.1 (duct design, which references ACCA Manual D) is kept without amendment. No DC checklist that requires a Manual D submittal was found.

Permit: DOB's mechanical permit covers 'Installation, repair or replacement of a refrigeration and/or air conditioning system.' Licensed contractors can get an Instant Permit for 'Installing not more than one new air conditioning unit, up to a maximum of 10 tons' or 'Repairing not more than one existing refrigerating or cooling unit, up to a maximum of 10 tons'. In 1-2 family dwellings, 'Repair or replace ductwork of a single HVAC system' is a Building Instant Permit scope. Load calc: DC R403.7 Exception 4 exempts a like-in-kind replacement from Manual S/J sizing when the new BTUs are equal or smaller and the envelope is not being altered.

DC R401.2: comply with '1. Sections R401 through R405' or '2. Section R406.' DC's R405 is an 'Additional Efficiency Package', not the IECC simulated-performance path. New buildings must pick at least one of: enhanced HVAC (Table R405.2, e.g. 15 SEER / 9.0 HSPF, 90% AFUE), enhanced envelope, enhanced air leakage plus HRV/ERV, or enhanced water heating. 'Alterations are exempt from Section R405.' R406 ERI must be 54 or less, and renewables cannot be used to meet it.

DOB 'Application to Install Air Conditioning and Refrigeration Systems in Buildings' (10/2022) asks for: type of work (new / replacement / remodeling / repair), proposed use, refrigerant type, condenser location, cooling method, power source, number of compressors, refrigerant-effect BTU/h range, equipment manufacturer/model, and Master A/C license. The form has no field for a load calculation. Trade permits must be pulled by a DC master-licensed professional. A DC R401.3 certificate is required 'For new construction and Level 3-alteration projects'.

DOB release of June 8, 2026: all 12 code categories (including residential, mechanical and energy conservation) will move to 'newer editions of the International Code Council (ICC) model codes'. Listening sessions end September 2026, the 'first set of proposed regulations in mid-to-late fall' 2026, the 'second set of proposed rules in the summer of 2027', and 'final rules coming in winter 2027'. The release names no specific edition (2024) and no effective date.

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