Idaho HVAC Specialty Licenses

Not every HVAC job in Idaho requires an unrestricted journeyman or contractor license. If your work falls within a narrow mechanical scope — installing hearth appliances, running LP gas lines, maintaining waste oil heaters, or fabricating fuel gas distribution piping — the Idaho Division of Occupational and Professional Licenses (DOPL) offers four specialty classifications that let you work legally without completing the full 8,000-hour apprenticeship and 120-question journeyman exam.

The trade-off is real: each specialty license draws rigid boundaries around what you can and cannot touch. Cross those boundaries on a single job, and you're performing unlicensed work in another regulated trade.

The Four Specialty Classifications

Idaho issues specialty licenses at both journeyman and contractor levels. Each restricts you to specific equipment types, BTU thresholds, or connection points.

Hearth Specialty covers installation of decorative hearth appliances — gas fireplaces, wood stoves, gas log sets — and their dedicated gas supply lines. You can run the gas piping to the appliance but cannot connect ductwork, install venting beyond the appliance's own exhaust, or make electrical connections. You still need a local mechanical permit from whatever authority has jurisdiction over the project site.

LP Gas Limited Heating Specialty allows installation, maintenance, and repair of liquid propane appliances, LP fuel gas piping, and related exhaust venting. The hard limit: nothing over 300,000 BTU input. That means no boilers, no hydronic systems, no ducted forced-air, no solid-fuel equipment, and no electric-fueled systems. A potable water connection — even for an LP-fired water heater — requires a licensed plumber.

Waste Oil Specialty restricts you to non-duct-connected waste oil heaters, burners, tanks, and their direct controls. Anything that extends beyond the burner and tank assembly — ductwork, line-voltage wiring, plumbing — must be performed by the relevant licensed trade. This is one of the narrowest specialty scopes in the state.

Fuel Gas Piping Specialty authorizes you to install fuel gas distribution piping only. You cannot terminate the piping at equipment, install appliances, connect chimney flues, or route venting. An unrestricted HVAC or plumbing licensee must handle the final terminations.

Exam Details by Specialty

Each specialty exam is shorter than the unrestricted exams and covers only the codes relevant to your scope.

The Hearth Specialty Journeyman exam runs 3 hours with 80 multiple-choice questions, requiring a 70% passing score. Reference books allowed are the 2018 International Fuel Gas Code (IFGC) and National Fireplace Institute training manuals.

The Waste Oil Specialty exam is 2 hours with 50 questions (70% to pass), referencing the 2018 International Mechanical Code and NFPA 31.

The Fuel Gas Piping Specialty exam is also 2 hours and 50 questions, tested solely against the 2018 IFGC.

LP Gas Limited Heating candidates also test through PSI Services under the same conditions as the other specialty exams — $75 per attempt, open-book with materials bound in three-ring binders, no sticky notes or loose paper allowed.

All exams are administered through PSI Services at testing centers in Boise, Coeur d'Alene, and Blackfoot.

Trade Scope Boundaries You Cannot Cross

Idaho Code § 54-5015 grants HVAC licensees specific limited exemptions to cross into electrical and plumbing territory during equipment installations. Specialty classifications are still bound by their own physical and technical limits, which are narrower than that unrestricted equipment-connection scope.

An unrestricted HVAC licensee can run 24-volt control wiring on equipment up to 5 tons and make line-voltage connections from a disconnect switch within 50 feet of the unit. They can install gas piping and closed-loop hydronic piping. Specialty licensees do not automatically inherit these cross-trade exemptions.

If you hold a hearth specialty license and an installation requires running a new electrical circuit to an electronic ignition system, that work must be performed by a licensed electrician. If your LP gas installation involves connecting a potable water line to a combination appliance, a licensed plumber handles that connection.

When a Specialty License Makes Sense

The specialty path is worth considering if you work in a narrow niche and want to start licensed work faster than the 4+ years required for an unrestricted journeyman license. Hearth installers, rural LP gas technicians, and fuel gas piping fabricators can all get to work sooner under a restricted classification rather than completing the unrestricted journeyman path. Pulling permits still requires a contractor-level license — specialty or unrestricted.

The risk is outgrowing the scope. If you find yourself subcontracting out work on half your jobs because your specialty license doesn't cover the full installation, the unrestricted license becomes the more cost-effective long-term investment.

For a complete breakdown of every license classification, the apprenticeship pathways, and how specialty credentials fit into a contractor business launch, see the Idaho HVAC License Guide.

Related Reading

• Idaho HVAC License Requirements — the full overview of all license tiers
• Idaho HVAC Exam — testing logistics, open-book rules, and PSI scheduling
• Idaho HVAC Contractor Bond Requirements — moving from specialty journeyman to contractor

See more Idaho guides →