Installation contract

The installation contract should provide you with a clear understanding of your solar project. The first few pages should include the system size, equipment specifications, total system cost, cost per watt, estimated production, and payment terms. The contract should also have warranty information, project start and completion dates, and any subcontractors involved. It is recommended that the installer offers a minimum five-year workmanship warranty to cover against work defects, component issues, and electrical output decline. Additionally, manufacturer warranties for solar equipment should be included. Some common contract elements are described below:

Timeline for installation

The installation timeline provides estimated dates for significant project milestones and an overview of the installation process.

Projected annual production

Your installer should provide an estimate of the system’s annual production and its expected performance over its lifetime. If offered, production guarantees should be carefully assessed, including the guarantee period, monitoring responsibility, and the conditions for guaranteed payments.

Customer disclosure form (SMART)

As part of the Massachusetts SMART program, installers are obligated to provide you with a Customer Disclosure Form, containing essential project details. This applies whether you’re pursuing direct ownership, third-party ownership, or community shared solar. The installer should provide the completed version of this form before you sign the installation contract.

Insurance coverage

To ensure liability protection, ask that a vendor carry a certificate of insurance for general liability and workers’ compensation insurance. Both are required to obtain a building permit.

Budget and payment schedule (for direct ownership)

An itemized budget should include potential additional costs or exclusions. The payment schedule should clearly outline the number, frequency, size, and due dates of payments. Any additional fees the installer charges should be disclosed upfront.

Changes and disputes

The contract should address how unexpected changes during permitting, installation, or inspection will be resolved. The process for notifying you about scope changes and non-refundable payment milestones should be included. A dispute resolution process, such as mediation or arbitration, should be specified.


Ensure that both equipment and workmanship are covered by appropriate warranties. Request equipment warranties that meet the requirements outlined below. Equipment should be UL listed and should also be on the California Energy Commission’s list of approved equipment, found here. The following warranty requirements are recommended:

Photovoltaic modules

Minimum one-year product warranty for workmanship and materials, with a minimum twenty-year performance warranty.


Minimum ten-year product warranty for workmanship and materials.

Mounting equipment

Five-year product warranty.


Minimum five-year labor warranty provided by the installer, covering defective workmanship, component breakdown, and degradation of electrical output. The warranty should encompass the entire solar electric project and should ensure that any necessary repairs or replacements are done at no cost during the warranty period.

The Office of the Attorney General’s FAQ about solar products for consumers in Massachusetts can provide helpful information and concepts to consider during the purchase of a solar PV system.

Additional considerations for third-party ownership

For solar leases or power purchase agreements, carefully review the contract terms. Items to consider include:   
  • Contract length.
  • Who benefits from incentives like tax credits.
  • Whether there is an option to buy the system at a later date.
  • Estimated annual utility rate increase.
  • Initial electricity price and price changes over time.
  • What happens at the end of a contract term.
  • What happens if you move out of the house or business before the contract term.

Discuss key terms of the contract that impact your overall benefit. For example, the fee for canceling the contract may cancel out any prior savings. The The Solar Energy Industry Association (SEIA) offers model documents that you can compare with the contracts you receive.

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Join the Clean Energy Transformation

Let's work together to reduce greenhouse gas emissions from our homes and build a clean energy future for Massachusetts.