Do I need a permit for HVAC work in
Williston, North Dakota?

Williston HVAC permits — the key details

The City of Williston Building Department enforces mechanical permits under North Dakota Century Code Chapter 54-21.3 (Uniform Construction Code) and specifically adopts the 2015 International Energy Conservation Code and Uniform Mechanical Code. Any new heating, cooling, or ventilation system installation requires a mechanical permit ($150–$400 depending on system type and tonnage). Replacement of an existing system in the same location with the same fuel type and venting arrangement is often treated as a simplified replacement permit (lower fee, over-the-counter approval, 1-2 days turnaround), but the city still requires you to file a form and have a final inspection. The key difference: if you're changing the system type (oil to gas, or adding a secondary heat pump), the permit triggers full plan review and engineering sign-off. Williston's mechanical inspector will specifically verify that ductwork is sealed (mastic tape and caulk on all seams), that the system is properly sized per Manual J load calculations for your home's climate zone, and that all combustion air and exhaust venting comply with the 2015 International Mechanical Code (IMC 501-504). For replacement furnaces, the inspector will check that the new unit fits in the existing space, that the gas or oil line is properly sized and vented, and that thermostat wiring is correct.