Vermont’s Integrated Applications Celebrates 50 Years of Sustainable Innovation, Sparked by a Vision for Change Solar

Brattleboro, VT – June 9, 2025 – Integrated Solar Applications (ISA), a cornerstone of renewable energy in southern Vermont, is proudly marking its 50th anniversary. Solar Applications Company was founded in Brattleboro in 1975 by electrical and mechanical engineer Alain Ratheau. Alain pioneered solar thermal, battery energy storage, small wind, and photovoltaic installations. This foundational commitment gained momentum in 2008 when Andrew Cay, an engineer and entrepreneur, acquired the company. With Alain’s continued expertise, Andy rebranded the company as Integrated Solar Applications, focused on combining technologies for net-zero energy.

ISA’s strength is its team, with extensive critical expertise in energy, building science, construction and business. Renewable energy expertise includes solar PV, battery energy storage, thermal, air source heat pumps, and ground-source geothermal. As market trends evolved, ISA became the leading photovoltaic installer in the area. The company has undertaken significant commercial and utility-scale projects, such as the 2.5 MW array between Exits 2 and 3 of Brattleboro and a 5.7 MW array at the Brattleboro Landfill. Katrina Wilson, Vice President at ISA, states “our dedicated and capable people with a great attitude and strong customer focus make the difference.”

Andrew Cay sees significant opportunity: “Integrated Solar has seen more advancement and change in the renewable energy industry in the last 15 years than the previous 35. Rapid growth has led to broad market acceptance, with a global market projected to reach $2.5 trillion by 2032. The stability of government support is vital for continued growth; the technology is sound and the economics work. Our collective choices will determine our future. I have hope.”

Alain Ratheau says, “In the early days, we focused on solar hot water and off-grid battery systems. Solar power gained attention in the 70s, stalled, then restarted in earnest in 2009. Lithium batteries began to migrate from power tools to EVs, and by 2016, when Tesla’s first lithium-ion battery Gigafactory was completed, the race for new battery technologies was on. Now these integrated technologies are rapidly advancing solar energy capacity.”

To celebrate five decades of powering a greener Vermont, ISA is offering a $500 discount for the first 50 customers who sign a contract and have a system installed. Customers should bring a copy of this press release to obtain their discount.

Discover how ISA can support your clean energy goals. Visit isasolar.com or call 802-257-7493.

A crew getting ready to go out the door!