Homeowner puzzled as solar panels produce far less power than expected on bright days

The homeowner said local installers were reluctant to take on the job, apparently because of warranty complications.

A Rhode Island homeowner said their rooftop solar setup was generating only 5 kilowatt-hours on a clear day, even though neighbors with a similar system were seeing roughly double that amount.

What happened

The home has two solar installations: a 13.5-kilowatt system and a separate 12-panel array. The homeowner described the setup in a Reddit post on r/solar and asked others to share their own production numbers.

Neither the app nor the installer’s diagnostic tools showed anything obviously wrong, and both indicated the photovoltaic strings were producing power. Still, the homeowner said the panels were delivering only about 8 to 10 kWh on clear days despite several hours of direct sunlight.

By comparison, a smaller 7.75-kW system on an unobstructed south-facing roof a few hours away averaged about 25 kWh per day over the same month, according to its owner.

Solar can be a strong way to cut home energy costs, but only when the system is installed correctly and serviced by reliable professionals. Homeowners can use EasyHome’s free explorer tool to compare potential savings from vetted installers in their area. Solar leases may also provide hundreds of dollars in monthly savings without upfront costs.

Additional details

The poster said the system had totaled 374 kWh over the month. During summer, however, a single day’s output had typically ranged from about 50 to 65 kWh.

The homeowner had moved in two years earlier, and the equipment had been out of service, leaving them without solid historical records for comparison.

Two other commenters reported monthly totals of 332 kWh from an 11-panel, 4.84-kW system and 501 kWh from a 16-panel installation. The first lived in Massachusetts, about 30 miles northeast of Providence. The second was a Newport homeowner whose system had generated 933 kWh in June.

The homeowner said getting the system serviced had been difficult, blaming the issue on warranty coverage concerns that discouraged local installers from stepping in.

What might help?

One Massachusetts commenter said a home solar array had stopped producing electricity for three days, but after an Enphase inverter reboot, output returned even though the system status had appeared normal the entire time.

"My solar installer monitors my system but hadn't noticed anything because the status was normal," the commenter wrote.

Monitoring tools can help homeowners catch problems before they become more serious.

The Rhode Island homeowner was already checking both the PWRview app and installer tools through a laptop connection. Anyone buying a home with existing solar equipment may want to review actual production records and confirm who is able to service the system.

EasyHome can also help homeowners compare vetted local installers and explore backup battery storage options. Adding a battery can help maximize savings and keep the home powered by solar when the grid goes down.

"Thankful I purchased the home with it but the amount of money and time I've already sunk into it and still not operating right is depressing."

More to read

Other homeowners have also faced the challenge of figuring out why their solar panels are not producing as much power as expected. Those cases have involved underperforming systems, possible wiring problems, unnoticed outages, and repair obstacles.

• A homebuyer's solar array produced a third of expected power, and installers wouldn't help.
• A UK homeowner's underperforming solar system may have had two roofs sharing one string.
• A solar owner received just $5 in credits before discovering half the system was offline.
• A Los Angeles homeowner reported falling solar output and a Powerwall that would not charge.
• An 82-kWh production reading led a homeowner to suspect years of solar system failures.