Mitsubishi Electric Diamond Contractor

Yes — whole-home gas-to-electric conversions are a core part of our work. We size heat pumps for calculated heating and cooling loads, plan electrical capacity, and coordinate distribution — not a same-size swap based on your old furnace label.

Modern cold-climate heat pumps perform well in Bay Area winters and summers when sized with Manual J and installed with proper distribution. Coastal microclimates and inland heat spikes are why we engineer each home — not assume one product fits all.

We are Mitsubishi Electric specialists and design around the best technology for your home — ducted, ductless, or mixed layouts sized with Manual J/S/D, not rule-of-thumb equipment swaps.

Manual J is the ACCA standard for calculating heating and cooling loads room by room based on your home’s envelope, windows, orientation, and local climate — not square footage rules of thumb. We use it to size equipment and duct systems so your system performs in real Bay Area conditions.

Square-footage rules ignore insulation quality, window area, shading, air leakage, and how your home actually gains and loses heat. Oversized equipment short-cycles, wastes energy, and struggles with comfort and humidity. Manual J matches capacity to measured loads.

Manual S selects HVAC equipment that matches Manual J loads without oversizing. Manual D sizes and lays out duct systems for proper airflow and static pressure. Together with Manual J, they form the engineering backbone of our design-build installs.

Many Bay Area projects qualify for federal tax credits, TECH Clean California, HEEHRA (income-qualified), and utility programs we support — including SJCE EcoHome Network, SVCE FutureFit, and Peninsula Clean Energy approved-contractor rebates — when equipment, sizing, and documentation meet current requirements. We design installs for program eligibility and provide documentation — we do not issue rebates or guarantee specific dollar amounts.

We are not a lender. We provide scope clarity, invoices, and installation documentation that support financing applications. Homeowners often use Synchrony or their own bank or credit union — we help you understand what paperwork your lender typically needs.

We serve homeowners across the San Francisco Bay Area — East Bay, San Francisco, Marin, Peninsula, Lamorinda, Walnut Creek, Tri-Valley, and South Bay — on design-build residential HVAC projects. We do not provide emergency repair or maintenance on existing systems we did not install.

Yes. Permit, Title 24, and inspection coordination are part of our design-build scope — not a surprise add-on at the end. We retain load calc and equipment documentation your jurisdiction and rebate programs commonly require.

No. We focus on project-based residential HVAC — heat pump installations, full-system replacements, remodels, retrofits, new construction, and ADUs. We do not provide emergency repair, routine maintenance, tune-ups, filter changes, or small service calls.

3rdGen Building Systems is the licensed mechanical contractor for commercial, industrial, and project-team work. 3rdGen Heating & Cooling is the residential HVAC division / DBA focused on homeowner design-build — heat pumps, remodels, ADUs, and whole-home replacements.