Building Doctors

Building Doctors operates as a BPI Certified insulation and home performance contractor serving the Los Angeles basin, including Silverlake, Pasadena, Venice, and Hollywood neighborhoods. Founded and led by Dan Thomsen, the team combines building science methodology with comprehensive energy auditing to treat homes as integrated systems. The company holds a 5.0-star rating across 14 client reviews, reflecting consistent delivery on promised efficiency outcomes and comfort improvements.

What distinguishes Building Doctors is their whole-house approach backed by genuine credentials: they are certified interpreters of HERS (Home Energy Rating System) reports and participate in the Energy Upgrade California Program, which enabled one client to secure an $8500 rebate toward insulation and HVAC upgrades. Their service menu extends beyond traditional insulation to include solar thermal and PV energy systems, whole-house air filtration, drought-tolerant landscape design, and EV charging infrastructure. This breadth allows them to address interconnected issues like duct leakage (one home had over 40% duct losses) and achieve net-zero readiness for clients.

Client testimonials name specific scenarios: Rich Sondheimer reduced his utility costs by over 60% after upgrading insulation and replacing HVAC, moving from a problematic 3-zone system to a single-zone setup that maintains consistent temperatures throughout his home. Another reviewer, Eric B., engaged them for a HERS rating on a 1930s Spanish bungalow, praising Dan Thomsen's extensive field knowledge and responsiveness. These accounts describe a contractor who prioritizes transparent proposals and fair solutions when unexpected issues arise during complex retrofits.