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Meet Our Team

Hans Rosenberger, President / Chief Engineer / Co-Owner

Altadena Energy & Solar was founded by Hans Rosenberger out of a belief that good engineering and financing are important for the development of environmentally friendly solar energy systems and buildings.  There is a strong demand for energy savings and ‘green power,’ but too few practitioners who understand both engineering and finance.  Hans majored in Physics at Goshen College, and completed his Masters of Electrical Engineering at Penn State. He pursued a career in radiometry-based remote sensing at NASA’s Jet Propulsion Lab (JPL) in Pasadena, CA, where he was staff engineer for 5 years in ground- and air-based microwave systems.  His work included field engineering at communication ground stations in California and Spain and airborne experiment campaigns in Florida and Sweden. He left JPL to pursue further aspirations in business and completed his MBA at USC’s Marshall School of Business.  During this time he pursued internships focusing on electrical efficiency and demand management for the frozen food warehouse industry in Delaware, and wind energy finance in Tehachapi, CA.

After his MBA, he started a property partnership in Berlin, Germany, to test the theory that there was unmet demand for green-oriented real estate development.  The real estate work led to the founding of Altadena Energy & Solar, and its partner firm in Germany, RSF Solar, with a focus on technically sophisticated solar and energy efficiency solutions for residential and commercial clients.


Hans is an active member of Pasadena Rotary Club and was a taskforce member of Senator Carol Liu's Green 21 initiative.  Hans grew up with the Mennonite community in Pennsylvania and now an active member of Throop Utilitarian Universalists Church in Pasadena. 

Joy Lam, Co-Owner/ Business Manager

Joy handles solar projects development and sales, utility relations and rebate processing. She also manage everything in our office and is our NABCEP PV Associate. Before switching her career path to renewable energy, she was a doctoral candidate researching sociology of religion and culture at University of Southern California.  She was the Operation Manager of the Arroyo Food Co-op in Pasadena CA, had lead the launch of Co-op store-front and was in-charge of its operation for two years. Joy is a Buddhist practitioner and is a member of the Order of Interbeing in the Thich Nhat Hanh Plum Village tradition.  

Robert Hawkins, Technician-in-chief

Bobby is our technician and oversee all projects on site. He has many decades of experience in construction, and continue to advance his skills in all the new electronic components in solar PV  monitoring system and energy storage systems. 

Anita King, Administrator

Anita will likely be the first person you talk to when you call our office. She handles all customer liaison for scheduling services and appointments, utility relations, permitting, and office management. 

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