HVAC Work
Mini‑Split HVAC Load Calculation & Specification Summary
**Project:** ADU Studio – Napa, California
**Prepared For:** Contractor Estimate and Supply Coordination
**Prepared By:** Christopher Naughton, AIA (Homeowner / Architect)
**Date:** October 2025
1. Project Summary
New 240-square-foot accessory dwelling unit (studio) in Napa, CA. Tight construction with
insulated walls, a ceiling, and a rigid‑foam insulated floor assembly. Three low‑E windows
(24" × 36") provide moderate solar exposure. Conditioned by a single Mitsubishi ductless
mini‑split heat pump system.
2. Design Criteria
• Indoor design: 75°F cooling / 70°F heating
• Outdoor design (Napa typical): 95°F cooling / 35°F heating
• Ceiling height: 8 ft (1,920 cubic feet)
• Envelope insulation: R‑19 walls, R‑38 ceiling, R‑20 floor
...