Session · Mechanicals and ventilation · Designers and consultants · Builders and trades

Right-Sizing Electric Hot Water Systems

Tom Sottile, Sunamp · May 7, 2026 · Chapter · NJPH (New Jersey Passive House)

Electrifying domestic hot water without overdesign in New York, where it can dominate energy use in Passive House buildings: direct electric, heat pump, hybrid low-amp, and central or point-of-use options, with Sunamp's latent heat storage as a case study.

Key points

• How thermal storage can support Local Law 97 compliance and decarbonization.
• How latent heat storage differs from conventional hot water systems.
• Low-amperage hot water electrification where electrical capacity is limited.
• Centralized and point-of-use systems compared: efficiency, space, and retrofits.
• Common sizing and retrofit pitfalls, and how to avoid overdesign.