New Hampshire Gas Fitter License

Any person who installs, services, or repairs natural gas or LPG piping, appliances, or venting systems in New Hampshire must hold a Fuel Gas Fitter license from the OPLC Mechanical Licensing Board. This requirement exists because of Amilia's Law, a 2007 consumer protection statute that made fuel gas work one of the few mechanical trades requiring state-level credentials in the Granite State.

The gas fitter licensing system is a ladder — four tiers with escalating education hours, field experience, and scope of authorized work.

The Four License Tiers

Fuel Gas Fitting Trainee

The entry point. You must be at least 16 years old, obtain a licensed gas fitter as your sponsor, and enroll in a board-approved educational program. The registration fee is $90.

As a trainee, you work under direct supervision of your sponsoring fitter. You cannot perform gas work independently or pull permits. The trainee period is where you accumulate the supervised field hours required for the next tier.

Fuel Gas Piping Installer (GPI)

The lightest full license. This credential authorizes you to install gas piping — the lines that carry natural gas or LPG from the meter or tank to the appliance connection point. It does not authorize appliance installation, service, or diagnostics.

Requirements:

• 60 hours of classroom training through a board-approved provider
• 1,000 hours of verified field experience within the preceding 60 months
• Passing score on the state exam (open-book, 70–75% minimum)
• $190 licensing fee

The GPI is the right credential for technicians who install piping but hand off the appliance connection to another specialist. It is also the fastest path to a full license for AC contractors who want to legally add gas line work to their service offering.

Fuel Gas Installation Technician

This tier authorizes gas piping installation plus appliance installation — furnaces, boilers, water heaters, gas ranges, and similar equipment. It does not cover service, repair, or diagnostics.

Requirements:

• 100 hours of classroom training (or GPI license + 40 additional hours)
• 1,000 hours of verified field experience
• Passing state exam score
• $190 licensing fee

The stepping-stone option lets you start installing appliances before committing to the full 2,000-hour service pathway.

Fuel Gas Service Technician

The comprehensive license. Authorizes gas piping installation, appliance installation, and full service and repair including system diagnostics. This is the credential most independent HVAC contractors ultimately need.

Requirements:

• 140 hours of classroom training (or Installation Technician license + 40 additional hours)
• 2,000 hours of verified field experience
• Passing state exam score
• $190 licensing fee

The classroom hours stack: if you already hold the Installation Technician license, you need only 40 additional classroom hours rather than repeating the full 140.

The Examination-First Rule

New Hampshire uses an examination-first sequence that catches many applicants off guard. You must register with an approved testing provider, pay the $100 exam fee, and pass the exam before submitting your OPLC application. If you submit an application without attaching a passing exam certificate, the OPLC will delay or reject it — and the $190 application fee is not refunded.

Approved testing providers include NH Gasfitters Continuing Education Online, Granite State Trade School, and Advanced Trade School. The exam is computerized and open-book, meaning you can bring physical copies of the 2018 NFPA 54 (National Fuel Gas Code) and the 2017 NFPA 58 (Liquefied Petroleum Gas Code). Plan to buy or borrow these references before test day.

Documenting Your Field Experience

Field hours must be documented using the OPLC's Affidavit for Proof of Field/Work Experience. Your supervising licensed gas fitter signs and swears to the hours, and must include their active license number on the affidavit.

Two rules that sink applications:

1. The 60-month window — all documented experience must have been completed within the 60 consecutive months prior to your application date. Hours older than five years are voided.
2. The supervisor requirement — the affidavit must be signed by a licensed gas fitter who personally supervised your work. Generic employer references or self-certification do not satisfy the board.

The Hearth System Specialty

In addition to the four main tiers, the board issues a Hearth System Installation and Service specialty license for technicians who work specifically on gas fireplaces, gas log sets, and venting systems. This requires 60 classroom hours and 2,000 hours of field experience — a high experience bar for a narrow scope, reflecting the fire safety implications of improper hearth installations.

After You Get Licensed

A personal gas fitter license authorizes you to perform the technical work, but it does not authorize you to operate under a business name, bid on contracts, or pull permits as a company. For that, you need a separate Mechanical Business Entity license from the OPLC ($250 biennially, though sole-licensee entities with zero employees are exempt from the fee under Mec 307.04(g)).

The entity license requires designating your personal gas fitter license as the qualifying credential for the business — meaning you are legally responsible for all mechanical work performed under that entity.

Our New Hampshire HVAC License Guide walks through the entire gas fitter pathway from trainee registration through business entity setup, including the exact application packet checklist and the common deficiency triggers that cause the OPLC to reject applications.

See more New Hampshire guides →