The Design Process


the design process of a solar electric installation is not a simple process. Each client is unique in their electrical demand as well as the usable structure and location of the PV system. A thorough analysis of those specific factors is critical to providing the ideal system to meet the demands of the customer.

Site Survey

NTREI will perform a visual hands-on site inspection of the property and roof or ground location where the PV system will be installed. The survey will include: Solar radiation data evaluation to determine the extent of any potential shading.

Examination of existing electrical service entrance capacity and location as well as calculate the maximum allowable inverter AC backfeed capacity. Also the condition of existing electrical wiring, breakers or other components that may affect the cost, NEC compliance or the installations ultimate performance.

The soundness of existing structural components that may affect the completed [rooftop] installation. Recommended upgrades, if necessary, to allow for a safe work area during installation and a long-term stable platform for the PV system mounting structure.

One hour of consultation outlining the results of the structural and electrical analysis. An honest and unbiased recommendation of the best components to meet the unique design criteria as well as energy offset requirement of the system owner. Answer all questions and address concerns about the installation and operation process.

After the onsite portion of the Site Survey, a complete Proposal will be developed from the data collected. An electrical and a structural design will be created along with a competitive priced Total Installed Cost. NTREI uses the latest design software including AutoCad™, PV Design Pro™ plus other manufacturer-specific design standards to assure a fully code compliant and efficiently operating system.

Final Proposal

Upon customer approval of the System Design Package and naming NTREI as the exclusive installer, NTREI will complete a Final Proposal which will list:

  • a description of the project,
  • the major system components and their manufacturers warranty period (if any),
  • approximate schedule for completion,
  • any mutually agreed upon changes,
  • the final cost for the complete installation
  • standard terms for payment of the installation charge.

Utility Interconnection Agreement (optional)

"If the buyer's installation will be connected, with permission, to the electric utility to allow the system to backfeed excess power onto the grid, the buyer may be required to sign an "interconnection agreement" with the local Transmission and Distribution Utility. (TDU) NTREI will, at the buyer's request, furnish the necessary form for the buyer's approval and signature, if possible. System owners are encouraged to thoroughly read and understand their obligations before agreeing to parallel connect to their utility grid. The PV system may be installed without complete approval by the TDU in an effort to meet installation scheduling requirements. Other utility requirements may apply and are the responsibility of the buyer."

If the customer is qualified for any incentive payments, NTREI will, at the customers request, complete and submit all necessary paperwork required to complete the application.


NTREI will warrant its installation workmanship and labor for 5 years and will support the customer in all verifiable manufacturers warranty claims.