How To‎ > ‎

Design Your Project

Using the data you collected in the evaluation phase, you can produce an actual system design detailed enough to determine your costs and benefits more precisely.

  1. Make a copy of the HAREI Generic Solar Install Template spreadsheet
    The spreadsheet is a Google Sheet; it will be easiest if you have or create a Google account so that you can make a copy.
    • Select the menu 'File -> Make a copy...' - name your copy using your last name (or other project label of your choice) as the file name
    • Open the INSTRUCTIONS tab for details of how to fill in the sheet
  2. Fill in the Panels and Inverters section with the number of panels you need.
    You can use the NREL System Advisor Model to explore design alternatives and how they trade off costs.
  3. Design your mounting system
    Most of our recent installations have used one of the mounting systems from IronRidge
    IronRidge Design Tool
    1. Go to the free online design assistant tool (you will need to create a free account)
      The tool supports creating roof and ground mount designs
    2. Costs will be slightly lower than those shown when you order with the HAREI discount.
    3. Save the project in the design tool
    4. Export the Bill of Materials from the tool, and copy each item into the Mounting section of the spreadsheet
      We strongly suggest adding a few extra of each of the small parts like panel clamps and mounting bolts.
    5. The tool will also help you produce drawings you will need when applying for permits.
    6. If you are doing a roof mount, you can further refine your plan by making a copy of the Roof Grid Tool spreadsheet (created by HAREI member Rob Figler) to calculate specific positions for the flash feet (on which the rails are mounted). Don't forget that you need feet near each end of each rail, and that it's a good idea to spread the load over as many rafters as possible.
  4. Contact HAREI to review your plan.
    We will help you refine the plan, and add your project to a group order.
  5. Determine applicable tax credits, rebates, and other returns.
    The spreadsheet will compute these for you.
    • There is a Federal Income Tax credit for 30% of your total installed cost (keep all receipts for related expenses!).
      This can include any costs for the project, including things like removing trees that would shade the array.
    • The New Hampshire Residential Small Renewable Electrical Generation Systems Rebate program is $.50 per watt of panel rated power (that is the DC output of the panels) up to $2,500, or 30% of the total facility cost, whichever is less. The NH rebate program has run out of funds, and is not accepting applications for the rebate at this time; we don't know when (or if) the legislature will renew funding.
    • For each megawatt (1000kwh) you generate, you create one Renewable Energy Certificate (REC), which can be sold at auction quarterly. Returns are variable; for this reason, we have not included REC revenue in our payback estimates - they're just gravy.
  6. You will need to create a detailed Electrical Installation Plan with your electrician


When your design is ready, it's time to apply for the permits and rebates you will need before you can begin installation.