Balcony Solar in New Hampshire: SB 540 and When You Can Use It

Short answer: not yet. New Hampshire's SB 540 was signed in July 2026 and will allow one plug-in solar device of up to 1,200 W per meter without utility approval, fees or a building permit. Part of the law starts on January 1, 2027, and use only becomes legal once the state Department of Energy certifies a recognized electrical standard for these devices. Until then, wait.

Status

Signed, not yet usable

Law

SB 540 (2026)

Maximum output

1,200 W, one device per metered customer

Starts

Partly Jan 1, 2027; use after DOE certification

Utility approval, fees, permit

Not required for compliant devices

Net metering

No

As of October 22, 2026, we haven't seen the Department of Energy's certification. We'll update this page and the state map as soon as it happens.

SB 540 was sponsored by Senator David Watters of Dover and passed with bipartisan support. Governor Kelly Ayotte signed it in early July 2026, making New Hampshire the latest New England state with a plug-in law, after Maine, Vermont and Connecticut.

What SB 540 will allow

• One portable solar generation device per metered customer, with up to 1,200 W of output.
• Connection through a standard three-prong outlet.
• No interconnection agreement, no prior approval and no utility fees for devices that meet the safety requirements.
• No building permit for compliant systems installed by homeowners or renters.
• Utilities are not liable for damage or injury caused by your device, and may create a platform where customers record the size of their system.

Why you have to wait

The law ties use to safety standards. Devices must meet standards set by a national testing laboratory such as UL Solutions, and the state Building Code Review Board is to update codes as that guidance comes out. According to the City of Dover, actual use "will not be legal until the Department of Energy first certifies" a nationally recognized electrical standard for plug-in systems. In September 2026, Dover's energy commission and its electrical inspector advised residents to wait before buying or plugging in.

The Department of Energy must also tell the public that connecting unlisted systems, or connecting them against the building code or the manufacturer's instructions, may affect your homeowners or renters insurance. That is good advice anywhere. The likely standard is UL 3700; see UL 3700 explained.

Older homes and two-phase wiring

Local officials raised two practical points. Many New Hampshire homes have older wiring, where "breaker masking" (solar feeding a circuit so the breaker doesn't see the full load) could let a circuit overheat. And a plug-in device feeds only one leg of a home's split-phase supply. Using a lightly loaded or dedicated circuit, and keeping total output at 800 W or less on shared circuits, reduces the risk. Read is plug-in solar safe?

Eversource, Unitil, Liberty and the Co-op

Once the law is usable, it applies to all distribution utilities. None can require approval or charge a fee for a compliant device. Plug-in devices are exempt from net metering, so exports aren't credited.

What a kit could save in New Hampshire

New Hampshire's average residential price was about 27 cents per kWh in July 2026 (EIA).

Estimates assume you use 80% of the output (95% for 400 W, 65% for 1,200 W) at 26.6¢/kWh. Try your numbers with the calculator, preset for New Hampshire.

What to do now

1. Don't plug in an uncertified kit while you wait.
2. Plan the spot: south-facing railing, wall or yard with little shade. See best angle and direction.
3. Ask your landlord or HOA early if you rent or live in a condo.
4. Bookmark this page; we'll note the date the Department of Energy acts.

Frequently asked questions