Gradient’s high-efficiency, 120v window heat pump plugs into a standard socket and is designed for easy installation with residents in place, enabling heating and cooling electrification without drilling, plumbing, electrical upgrades, or major retrofits. The heat pump provides room-by-room temperature control, improving comfort by replacing centralized systems like boilers, with flexible, unitized HVAC. The system delivers efficient performance even in cold climates, helping reduce energy costs and emissions. Gradient’s design uses low-GWP refrigerant sealed at the factory, minimizing leak risk and eliminating the need for field refrigerant connections.

- Minimally-disruptive, quick installation - Gradient's heat pump uses the existing hole in the building's envelope: the window. The mounting bracket requires no drilling or structural modifications. Installation does not require permitting. Built-in atomizers convert condensate into outdoor mist, eliminating plumbing and building alterations. No drainage is needed. Plugs into standard 120v outlet. - Efficiency in extreme temperatures - The heat pump system delivers efficient performance even in cold climates - Enhanced air quality - Optional MERV 13 filtration captures fine particulates and enhances indoor air quality.

- Electrify building heating and cooling - Install high-efficiency heating/cooling in building - Regulate indoor temperature by unit or zone - Improve tenant control over traditional central systems - Reduced risk of refrigerant leaks in a building/portfolio - Low barrier path to building HVAC electrification, no panel upgrades & easy to install

Gradient's pilot at NYCHA demonstrated up to 60% cost savings when compared to baseline steam radiators. ACEEE has published a report finding that, of the space heating decarbonization options for centrally heated multifamily buildings, window heat pumps generally have the lowest life-cycle capital and energy costs.

Gradient units replaces low-efficiency fossil-fuel or electric-resistance heating with high-efficiency heat pumps and upgrades low-efficiency window AC units to models that use about 54% less energy. Moreover, room-to-room tenant controls allow residents to reduce unnecessary energy use.

Existing building retrofit

Gradient’s All-Weather 120V unit can fit windows with a minimum width of 26”. Each window heat pump unit plugs into a standard 120V outlet within 6 feet of the installation (no electrical panel upgrades), and is designed to operate in most climates, from -13°F to 115°F. Other required installation conditions: - Wall depth of 6.25 to 20 inches (measured from the inside window sill to the outside wall) to fit the mounting bracket. - Stable window and surrounding structure that can safely support the unit and bracket (total weight about 140 lbs). - Window that is at least 21 inches above the floor for safe installation. - Clear space around the outdoor side of the unit to ensure proper airflow; avoid spots blocked by walls, plants, or furniture.

Buildings which are master-metered (where the owner pays one utility bill for the whole building) or buildings that are fully tenant metered (where each unit has its own meter). Building wide WiFi preferred but not necessary.

Minimum project size is a multifamily building (typically 5+ units).

Preferred project size is larger buildings, i.e., 10+ dwelling units; dorms; manufactured housing; ADUs etc.

Gradient reccomends that their units are connected to WiFi to ensure that their customer service team can proactively monitor and address issues if they arise. Graident also offers a building management system for its fleet of units, Nexus, which enables building owners to monitor the energy usage and performance of their fleet on the back end. Nexus will also integrate demand response capabilities this year. In spaces without a window, building owners could consider pairing window heat pumps with packaged terminal heat pumps, although this increases the amount of construction involved.

No specialized skills or tools are required for installation. Gradient is actively developing its qualified installer network conducting trainings with contractors who would like to learn how to install and service our equipment. Gradient will also train building maintenance staff on installation procedures and routine maintenance. See Gradient's installation manual for more info - .Attachments_Other_Gradient.pdf

Gradient currently works directly with building owners to retrofit central heating and cooling systems with their window heat pumps. Eventually, Gradient heat pumps will be available in more traditional direct to consumer channels (i.e. Home Depot, Lowes, Costco, etc)

New York City Housing Authority, Boston Housing Authority; Lynn Housing Authority; Providence Public Housing Authority

Attachments_CaseStudy_Gradient.pdfBoston is piloting window heat pumps in affordable housing

System takes about 30 minutes to an hour to install. Installation does not require any drilling or permanent alterations. This significantly reduces tenant disruption given the short installation time.

There are multiple ways for a tenant to use their Gradient heat pump. The onboard user interface (UI) allows users to change set point, mode, and fan speed directly on the unit. The unit also comes with a remote and an app. The app allows users to control the unit remotely and set schedules.

- NYSERDA PON 6037 - CPC Climate Friendly Homes - Clean Energy Investment Tax Credit

Gradient systems have an MSRP of $3,500, with bulk pricing available based on order volume and timing.

Gradient's warranty includes 1-year parts & labor limited warranty: free repair or replacement of defective parts, including labor, through an authorized technician; Additional 4-year parts-only limited warranty: years 2-5 include free replacement of defective parts (labor not included); Post-warranty costs: users should expect costs for filter replacements and routine maintenance.

Pay back periods depends on existing heating and cooling systems when estimating cost savings, and also on labor costs when determining O&M expenses. For example, Gradient window heat pumps are 4x more efficient than electric resistance heat and the New York City Housing Authority reduced their monthly bill by 60%.

Similar to most other HVAC units, the heat pump has an indoor air filter that must be cleaned periodically. The heat pump also has a condensate filter that requires periodic cleaning. Cleaning in both cases must be done following the instructions in the manual.

Like other heat pump systems, the Gradient Window Heat Pump involves a modest learning curve for residents. Gradient recommends a “set it and forget it” approach, consistent with best practices for heat pump operation. Early deployment data suggests some residents continue to use the system like a traditional window AC, turning it off or unplugging it when leaving the room, which reduces efficiency. Gradient is expanding tenant education efforts to encourage more effective, energy-efficient usage. For building management, training and adoption are relatively straightforward. Installation is simple, typically completed in under an hour, and routine maintenance takes about 10 minutes per unit. Staff at early deployment sites have reported spending significantly less time on maintenance compared to legacy systems such as steam radiators.

Gradient trains technicians to maintain systems; maintanance is similar to mini-split maintanance. Units come with a 5-year standard warranty: first year covers parts and labor, and the following four years covers parts. Additional repairs can be done by a qualified Gradient technician.

Gradient’s NEXUS platform is a building wide fleet management tool for multifamily owners and operators, housing authorities, campuses, and organizations; features include: - Smart Set Point Guardrails - Personalized Tenant Comfort - Lower Downtime with Proactive Maintenance - Weather & Usage based Load Forecasting - Demand Response Integration

Factory-sealed low GWP R-32 refrigerant design reduces leakage by 89-95%, unlike traditional HVAC systems.

UL 60335-1; UL 60335-2-40; DOE CFR; ENERGY STAR Version 5.0; ENERGY STAR Most Efficient 2025; CEE Advanced Tier Certification