New Hampshire permit guide
Do you need a permit to replace windows in New Hampshire?
Plan on it. Window and door replacement is not on the state building code's list of permit-exempt work, anything that changes a required egress is never an ordinary repair, and the energy code sets minimums for the replacement units. The permit comes from your town under RSA 155-A, and a few towns issue none. Here is where the line falls.
The rule that applies to every trade
New Hampshire has one building code for the whole state. Under RSA 155-A the State Building Code, the 2024 International Residential Code for one- and two-family homes and the 2023 National Electrical Code, each with New Hampshire amendments, applies in every city and town, and a permit is required before work covered by the code begins. What differs from town to town is the office that issues it: the state leaves permits, inspections and fees to each municipality, which is why each town page on this site starts with that town's building department.
Who applies is more open than in some states. The code lets the owner or the owner's authorized agent apply for a building permit, and New Hampshire issues no statewide general contractor licence. The trades are another matter: electrical installations need a licensed electrician, and gas fitting and plumbing need a licence from the Mechanical Licensing Board, in each case with a permit and inspection. The statute is explicit that the contractor is responsible for meeting the code, so the usual arrangement is that the contractor doing the work pulls the permit under their own licence.
Sources: RSA 155-A, New Hampshire Building Code (gc.nh.gov); NH Division of Fire Safety: State Building Code; International Residential Code 2024, Chapter 1 (ICC); OPLC: the licensing boards; RSA 319-C, Electricians (gc.nh.gov); RSA 153:27–36, plumbers and fuel gas fitters (gc.nh.gov).
Which code applies, and who issues the permit
The code is set at state level. The State Building Code Review Board recommends code updates and reviews the New Hampshire amendments, and the Division of Fire Safety publishes the adopted editions: from 1 July 2026, the 2024 International Residential Code and the 2018 International Energy Conservation Code, each with New Hampshire amendments, and the 2023 National Electrical Code. During the concurrence period to 31 December 2026 an application may follow either the 2021 or the 2024 codes, but not a mix of the two; from 1 January 2027 every application is under the new codes, and the edition in effect when the town receives the application governs the job to the end.
Enforcement is local, and it is the town's choice. RSA 155-A reserves permits, certificates of occupancy and fees to cities, towns, counties and village districts; a municipality that enforces the code adopts an ordinance, a building official who issues permits and inspects, a fee schedule, a building code board of appeals, that the Building Code Review Board must confirm, and local amendments may not be less stringent than the state code, may not touch its technical requirements and, since 1 July 2026, are limited to administrative matters. A few towns issue no building permit at all: Epsom has adopted no building codes and issues only a zoning permit, Wilmot has no building inspector, and Thornton issues a zoning compliance permit with no inspections. The state code applies in those towns all the same, and the contractor is responsible for meeting it.
The three towns have their own pages: Epsom, Wilmot and Thornton.
Sources: NH Division of Fire Safety: State Building Code; NH Division of Fire Safety: State Building Code Review Board; RSA 155-A, New Hampshire Building Code (gc.nh.gov); Town of Epsom: Zoning Compliance; Town of Wilmot: Planning Board; Town of Thornton: Zoning Compliance & Enforcement.
Windows and doors in New Hampshire
Replacing windows or exterior doors is not on the code's list of work exempt from a permit, that list is finish work such as painting, tiling, cabinets and counter tops, small detached sheds, fences and low decks, so plan on a permit in your town. The code's own exception for ordinary repairs stops at anything that removes or changes a required means of egress, which is exactly what a bedroom window is, and enlarging or shrinking an opening alters the structure. Whether a strict like-for-like swap in the same opening counts as an ordinary repair is your building department's call, so ask before assuming.
New Hampshire issues no statewide licence for window or door installers, so the permit is the record of the work: it is issued by the town under the state code, and the owner or the contractor as the owner's agent applies for it. If your town has a historic district, the state statute leaves historic district ordinances fully in force, so exterior window and door changes inside one usually need the historic district commission's approval before the building permit issues.
The energy code applies to replacement windows. Under the 2018 IECC with New Hampshire amendments, a replacement fenestration unit, sash and glazing included, must meet the U-factor and solar heat gain limits in the code's table, with an area-weighted average allowed across several units; a glass-only replacement in the existing sash and frame is a repair, and storm windows over existing windows are exempt. The New Hampshire amendments add a standard energy code form to the code, and the Division of Fire Safety posts a residential energy code application on its State Building Code page.
Sources: International Residential Code 2024, Chapter 1 (ICC); RSA 155-A, New Hampshire Building Code (gc.nh.gov); OPLC: the licensing boards; 2018 IECC with New Hampshire amendments, Chapter 5: existing buildings (ICC); NH Division of Fire Safety: State Building Code.
NHSaves rebates
NHSaves lists no rebate for windows or doors as such. Its Home Energy Performance program pays incentives and offers low-interest financing for insulation, air sealing and other approved energy efficiency updates, after an energy audit for which the online Home Heating Index tool checks your home's eligibility. Whether a window project counts is your utility's call, Eversource, Liberty, Unitil or the New Hampshire Electric Co-op, and the town's permit is separate from the rebate paperwork.
Sources: NHSaves: energy audits and weatherization (Home Energy Performance).
Questions homeowners ask
Do I need a permit to replace windows in New Hampshire?
Plan on it. Window and door replacement is not on the code's list of permit-exempt work, and the ordinary-repairs exception excludes anything that removes or changes a required egress, which a bedroom window is. Whether a same-size swap counts as an ordinary repair is the local building department's call.
How long is a building permit good for in New Hampshire?
Under the International Residential Code as adopted by New Hampshire (section R105.5), a permit becomes invalid if the work has not started within 180 days of issue, or if more than 180 days pass between inspections once work has begun; the building official may grant written extensions of up to 180 days at a time. An application that is filed but not pursued is treated as abandoned after 180 days.
Are building permits public record, and how do I look one up for an address in your town?
Yes, permits are public records. Ask the building department in your town how to search by address, or check the town's online portal if it has one.
Can a homeowner pull their own permit in New Hampshire?
Often, yes. The code lets the owner apply for the building permit, and New Hampshire's licensing statutes let the owner-occupant of a single-family home do their own electrical installations and, in an existing single-family primary residence, their own fuel gas fitting: still under a permit, to code and with the town's inspection. A licence is required for anyone else doing that work. Most homeowners still let the contractor pull the permit, because the statute makes the contractor responsible for meeting the code on the work they do.
What happens if work is done without a permit?
The town can order the work stopped, opened up for inspection, corrected or removed, and the code provides penalties for building or altering without a permit. Unpermitted work also surfaces at sale, when a buyer's attorney searches the permit history. It is far cheaper to permit it the first time.
Related New Hampshire permit guides
- Do you need a permit to replace a furnace, boiler or AC in New Hampshire?
- Do you need a permit to replace a roof in New Hampshire?
- Do you need a permit to replace siding in New Hampshire?
Looking for your town's building department, permit portal and recent filings? Find it on the New Hampshire town pages.