Step 3. How do I estimate my rebate and project savings?

Rebates are based on the size of the solar PV system.  To determine how large of a system you plan to install, you should contact an installer.  However, you can estimate the size system you will need based on the following:

1. Check your electricity bill for the electricity usage kWh. 
2. Estimate this over the course of one year.

• Some PV Facts:
• Optimal solar PV systems in Massachusetts will produce about 1,200 kWh per year, per kW correctly installed.
• This means if you install a 25 kW system, this will provide you about 30,000 kWh per year
  (25 kW x 1,200 kWh = 30,000 kWh).  Estimate what size (kW) system you will need based on your annual usage (kWh).

3. Estimate your available roof space or land area for the PV system.  A 1 kW system needs approximately 100 sq. ft.  A 10,000 sq. ft. roof could potentially hold a 100 kW system.
4. Click on the “Commercial Rebate Estimator” top right to calculate your rebate

Commercial Rebates – For Commercial Projects Only

Rebates for a commercial project will be capped at the lesser of:

• 100% of total installed costs, except in the case of projects receiving the Green Schools Adder which will be capped at 90% of total installed costs, or
• A rebate based on a maximum system size of 200 kW even if the system is larger.
• Residential end-use facilities which must use the Commercial application and rebate matrix are capped based upon the lesser of a 5 kW (DC @ STC) maximum per dwelling unit or $20,000 rebate per dwelling unit. This applies to residential third-party ownership or leasing arrangements, and/or to new construction developments of more than one unit of residential homes, apartments, or condominiums. The 5kW (DC @ STC) or $20,000 cap per dwelling unit also applies to any property with a residential end-use that is applying via the Commercial application process. This includes any building that has residential dwelling units and/or sleeping beds with the exception of health care facilities or hospitality facilities such as hotels, motels, bed & breakfast lodging, rooming houses, hostels, licensed group homes, dormitories, and other such short-term housing for hire facilities.
• In addition, a single Customer Entity can be awarded no more than $1,600,000 in total Commonwealth Solar rebates per calendar year.

The current rebate levels are:

Some things to do before contacting an installer (from Solar Boston):

• Assemble the previous year's electricity bills
• If you are in a historical district, check in with the Boston Landmarks Commission at 617-635-3850 to learn more about additional aesthetic guidelines for your solar installation.
• If you have easy access to your roof, take a few notes on it.
• How big is it?
• What is it made of?
• When was it last replaced?
• Is it flat or pitched? If it is pitched, in which direction does it face (e.g. due south, southwest, etc.)?
• Is there anything on the roof, or is the roof cluttered with mechanical equipment, chimneys, roof decks, etc. that take up real estate or could potentially shade solar systems?
• Check out your southern exposure. Is there anything to your south (e.g. trees, etc.) that would shade your system?
• Have you had an energy audit in the last 6 years?  The rebate application requires it, so having the appropriate paperwork handy will help streamline the application process

Other Available Incentives – Please consult the Database of State Incentives for Renewable & Efficiency www.dsireusa.org to find information on other incentive programs