SERVING THE NORTH BAY
System Design & Load Calculations
Manual J and Manual D Engineering for New Builds and Full System Replacements.
Proper HVAC design is the foundation of a system that performs the way it should. We perform Manual J load calculations to determine the exact heating and cooling requirements for your space, and Manual D duct design to engineer a distribution system that delivers conditioned air efficiently to every room. This level of detail matters most on new construction, full system replacements, home additions, and any project where the existing design is not working. If you want a system built on actual engineering rather than guesswork, this is where it starts.
Your Comfort is our Legacy.
Comfort isn’t luck, it’s built. At Legacy Heating & Air, we design, install, and repair systems with precision, from accurate load calculations to properly engineered ductwork. The result is consistent comfort, lower energy waste, and a system that finally performs the way it should.
LICENSED & INSURED
CSLB Certified Technicians
WHO OFFER
Furnace & A/C Repair
When your system breaks down, we fix it fast and fix it right. We accurately diagnose furnace and AC issues, use quality parts, and make sure everything is running properly before we leave. No guesswork, no shortcuts, just reliable repairs you can trust.
custom ductwork & replacement
Most comfort issues start in the ductwork. We redesign and replace ducts using proper Manual D calculations to eliminate leaks, improve airflow, and balance temperatures throughout your home. Ideal for older homes, difficult layouts, or systems that never felt right.
Furnace & a/c Replacement
Full system replacements built around your home, not a one-size-fits-all unit. We use proper Manual J load calculations to size your system correctly, improving comfort, efficiency, and long-term performance. Lower energy bills, better airflow, and a system that actually keeps up.
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Serving Sonoma, Napa, and Marin County. Honest recommendations. No pressure.