In October 2023, I had 23 solar panels installed on my roof in the Boston area. This post series will summarize our experience with the system thus far.

Procurement Process

We went with a company out of Arlington, Massachusetts, for the project. I found the company using EnergySage, a quote aggregator. EnergySage is a convenient way to get multiple quotations from different local companies. There are others, including Solar.com, who provide a similar service. EnergySage is a Boston company, so I preferentially chose them.

The quoting process with EnergySage is straightforward. You put in information about your house, which gets farmed out to several companies to provide budgetary quotations. They provide a convenient comparison table for the quotes. In my case, I received seven quotations back, with more or less equivalent equipment. I selected a subset of these to pursue further – some quotes were well out of line with the others. Two of the vendors were very responsive, and I selected one of them.

The nice thing about EnergySage is that their platform shields you from receiving spam calls. You can communicate with the companies through their portal before providing your contact information to the short-listed companies. I started seriously considering PV in 2021 and went through a round of project quotations before pulling the trigger in 2023.

System Description and Costs

In August 2023, the winning quotation priced the system at $3.26/W for Hanwa Q-Cells 405W panels paired with Enphase IQ8-M inverters.

Based on a report released by EnergySage (“Energy Sage Marketplace Intel Report H1 2024” n.d.) in October 2024, I paid what has become the average cost today. If you’re interested in PV, this report is a good read on the current market situation. It’s incredible how cheap solar can be in areas that don’t have good net metering policies and cheap labor.

After tax credits, the system was around $20k. Both tax credits came back in early 2024 when I submitted my taxes for 2023. The tax credit is non-refundable, meaning you need to have a tax liability larger than it to take full advantage, though it is possible to carry it over to a subsequent year.(“Homeowner’s Guide to the Federal Tax Credit for Solar Photovoltaics” n.d.)

Other related expenses include:

Although necessary for the project, these expenses are not formally considered part of it. My roof already needed replacement, and the electrical panel replacement happened as part of a broader household electrification effort. Including these as part of the ROI calculation is not fair.

The final design for my system included 23 Hanwa Q-Cells Q.PEAK DUO BLK ML-G10+ panels. These panels are paired with Enphase IQ8M microinverters to reduce the amount of clipping. The inverters have a maximum output power of 325W, which is about 25% less than the solar panel’s maximum output. Even the panels can cause clipping on the inverters, this is occurs rarely. Panels are usually not installed in ideal locations – the panels are not facing due south or on a tracker, they’re not at the perfect angle, etc.

Clipping on our system has happened since the inverters are undersized compared to the panels, but it’s not common. Figure 1 shows an example of when this happens. It took some digging to find this in my archives.

Process

After signing the contract to move forward with the system, a representative from the vendor came out to visit my home and make some measurements of the roof. They took photos of the electrical panel and looked in the attic at the rafters to check the spacing and size.

After this, the engineering team at the vendor got to work and submitted a pile of paperwork to the utility and my city to obtain the necessary approvals and permits. The design underwent multiple iterations due to some new fire code requirements described in Headaches.

The timeline from signing the papers to getting Permission to Operate (PTO) was 108 days. The actual installation took only two days.

During the installation, there were two inspection steps. The city is supposed to inspect the physical installation to ensure that all setbacks are maintained and the system properly ties into the framing. They are also required to sign off on an electrical inspection after everything is tied in. After this inspection, the installer can ask the utility to make the meter swap and grant permission to operate the system.

In my case, I believe that the city waived the physical inspection of the equipment, but they did come out for the electrical inspection.

Kudos to the technician from Eversource for working Black Friday and swapping my meter out.

Headaches

Setback Requirements

On December 9, 2022, the Commonwealth of Massachusetts adopted the 2021 NFPA 1 fire code. The new edition makes the access requirements on the roof stricter than in the past.A 36" walkway on the roof plane is now required, and the setback from the roof ridge should also be 36".

Section 11.12 describes the requirements for photovoltaic systems, but due to some crazy licensing restrictions I cannot copy the relevant sections here. They may be viewed here for free, but an account is necessary. They also have ridiculous password requirements, considering it’s a free account.

Unfortunately, this new code means we had to install a smaller array than the initial design. We lost four panels from the south-facing portion of the array and had to put some panels onto a less productive face.

Equipment Problems

Thus far, we had one issue with the system at installation. All of the microinverters communicate with a piece of equipment called the IQ Combiner 4.

This unit manages:

• Monitoring the grid connection to shut off the power if the grid drops.
• Communicating with the microinverters underneath each panel.
• Monitoring the power output and, optionally, consumption from the electrical panel
• Sending data to the Enphase Enlighten monitoring system.

The Ethernet connection on the IQ Combiner 4 unit was faulty. The Enphase remote support RMA’d a board for us and, the installer replaced it during a follow up visit.

Since then, we have had zero issues.

Next Steps

In the next post, we’ll review the system’s electrical performance, and in the third post in this series, we’ll cover the financial performance.

References