Increasing the Thermal Range and Efficiency of Affordable User-Installable Room Heat Pumps

Treau, Inc.


San Francisco, CA

Recipient Location


Senate District


Assembly District



Amount Spent



Project Status

Project Update

Kicking off this grant in 2021, Gradient is making important progress towards the optimized fan system by engaging multiple custom fan design firms with requests for quotes to determine these companies' capabilities. Based on these conversations, Gradient is now focusing on designing custom fan housings and using off-the-shelf blades, which will likely allow them to meet performance targets with significantly lower technical risks. Additionally, Gradient is optimizing fan motors for a revision of the polymer heat exchanger designed to integrate into the product. Finally, tube-fin heat exchangers are being evaluated for improved low temperature performance, using a high accuracy test stand specifically designed and built by Gradient.

The Issue

There are limited energy-efficient and all-electric solutions for space heating and cooling for multi-family and low-income homes. In the US, heating and cooling in buildings constitutes 15% of all energy use. The entire heating, cooling, and refrigeration sector produces more emissions than the transportation sector. The growing energy demand and CO2 footprint must be reduced by using low-Global Warming Potential refrigerants and replacing methane heating with electric heat pumps. Multi-family and low-income residences are limited to poor-performing window and portable ACs with few efficient and low-carbon options compatible with their buildings, budgets, and needs.

Project Innovation

Building HVAC systems consume more than 15 percent of all U.S. energy and contribute more to global warming than the entire transportation sector largely due to the high global warming potential (GWP) refrigerant leaks. A significant breakthrough in building cooling technology that uses low-GWP refrigerants, is low cost, and has high efficiency is needed. The Recipient will develop customized fans, heat exchangers, and cold climate configurations that optimize the thermal performance and minimize power consumption of a high efficiency, low cost, low-GWP refrigerant HVAC system with the potential to reduce building air conditioning energy consumption by up to 30% and greenhouse gas emissions by 50 percent.

Project Goals

Advance the Recipient’s HVAC technology from alpha prototype to pre-production prototype.
Establish a pilot production.

Project Benefits

Drawn from user research studies, Gradient systems have a strong customer appeal due to their low noise, low profile, ease of install, and low cost. Today, users of window air conditioners must lose use of their window, and suffer with ugly, noisy systems. Gradient’s technology allows these customers to get their window back, let more natural light and fresh air into their homes, reduce noise, improve room aesthetics, and reduce the carbon footprint of their home energy use. This has been supported by a number of press articles written since revealing our product and a customer waitlist of 34,546 emails.



Increasing the thermal range of heat pumps can expand the geographies where heat pumps can be deployed, bringing more options for electrification to more communities.

Key Project Members

Project Member



Optimized Thermal Systems, Inc.


CFturbo, Inc.


Match Partners


Treau, Inc.


Contact the Team