2021 Quick Start Grant Recipients

Small Planet Supply

Read about this program and its findings:


Small Planet Supply will install a packaged, natural refrigerant central heat pump boiler in a 40-unit low-income farmworker community in Delano, CA to test the viability of this novel, easy-to-install solution for other similar buildings.

Market Barrier

Currently, there are limited options for central heat pump boiler systems to serve small multifamily buildings, which are especially common in rural areas. These systems must be custom designed, leading to inconsistent sizing and plumbing strategies across projects. A typical plumber’s prior experience with traditional gas boilers is often inapplicable, leading to installation errors and field installations that vary from project to project.

Proposed Solution

Small Planet Supply has created a pre-designed custom central heat pump boiler system using CO2 as a refrigerant (the “Droplet” system), which it will install in a new 40-unit, 5-building, low-income farmworker family community developed by the Housing Authority of Kern County.  The components of the 9 kW system are assembled for each system to be ready for single-point water and electrical connections.

Theory of Change

This innovation—delivering heat pump boilers in pre-engineered, factory-completed packages that can be easily installed—could be key to the expansion of heat pump boilers into the boiler market.

Project Status:


Housing Type:

Multifamily deed-restricted affordable housing


“Droplet” heat pump boiler system with CO2 refrigerant


Delano, CA