Welcome to A1 Sun

After installing solar on our own home and business, our neighbors wanted their own systems installed. For the benefit of our neighbors, our community, and the larger global environment, we incorporated A1 Sun, Inc. with the goal of installing superb, affordable photovoltaic and thermal solar energy systems. A1 Sun is located in Berkeley. We serve the surrounding counties of Alameda, Contra Costa, Marin and beyond.

A1 Sun offers a custom onsite evaluation and Free Solar Estimate for your home and business.

We believe in solid
We believe in solid
enduring quality
enduring quality
Harmony with the Earth
Solar is in harmony with the Earth,
Harmony with the Air
Harmony with the Water
and Water.
Upgrade your home and add value
Upgrade your home and add value.
Solar (wait...)
It's Beautiful.
It's beautiful.

Get Solar

It's easy with A1 Sun:

  1. Get a Free Solar Estimate
  2. A custom design, to fit your needs and budget
  3. A professional, careful build
  4. We take care of all paperwork
  5. Connect to the grid and start saving!

Highlighted Vendors

What we Do

We design and build

  • Photovoltaic (create electricity),
  • Thermal (heat your water), and
  • Vehicle charging (charge from solar)


We provide

  • Systems maintenance,
  • energy Analysis, and
  • project Consulting


We work with

  • Residential and
  • Commercial


Why Solar?

It is a great time to go solar:

  • 30% Federal tax credit
  • Reduce or eliminate electricity bills
  • Add value to your home or business
  • Solar is more affordable than ever (panels are 70% less than 5 years ago)
  • Be part of the Green Revolution, and help save the planet!

Interested? We can provide a Free Solar Estimate for your home or business.

What Customers Are Saying

The A1 Sun Customer Experience
I decided to "Go Solar" last summer and called Larry Giustino at A1 Sun, Inc. Careful, efficient, outstanding workmanship - the process was painless.
– Helen Green, I.E.P., Berkeley
A1 Sun was an A+ experience for me. They came over in person, laid out a comprehensive plan, and provided thorough answers to all my questions. Their bid gave me all the information I needed to make a decision. A1 took care of all the applications and paperwork, and did the installation quickly and professionally. Throughout the installation, the team was polite, friendly, and always cleaned up after themselves. These people don't take short cuts - they get it done right.
– Peter Hobe & Christina Crowley, Berkeley
My experience with A1 Sun has been great! Not only was the work done on time, on budget, and exactly as promised, but Larry has gone way out of his way to help with forms, bureaucracy, and new developments. I couldn't recommend this company more enthusiastically.
– Joe and Betsy Schlessinger, Berkeley
Thanks again for all your help and committed follow through after the installation. As I am sure you know, that is a rare thing in the trades.
– Dave and Corrie Winnacker, Albany
I'm a very happy customer. I am thrilled at the prospect of a sunny power generating summer!
– Margaretta Lovell, Berkeley
Thanks for all your work, not only on the installation, but on the mountain of paperwork!! We received our rebate for a dollar more than you predicted.
– John and Lisa Doyen, El Cerrito
As a parent, I want to do whatever I can to help ensure that our planet remains viable for future generations. I decided to invest in Solar. Using A1 Sun was a terrific experience. The A1 Sun team was friendly and non-intrusive; they left no footprint other than the functioning solar panels on my roof. A very satisfied customer.
– Ann Rowland, Berkeley
We had a leak in our vintage solar hot water system installed by another solar company. A1 Sun responded quickly, diagnosed and solved the problem. I'm a happy customer.
– The Country Joe and Kathy McDonald Family, Berkeley