Apartment buildings have missed out on rooftop solar. A shared battery is built to let units split the power

Solar for apartment buildings has trailed single-family rooftops for years, because the panels would sit on one roof shared by many separately metered homes. On November 10, 2026, Holu Hou Energy of Menomonee Falls, Wisconsin, introduced HoluPower 3.0, a battery it says lets every unit in a building draw on the same solar array and storage.

Key points

• About 49% of U.S. households could not host a solar system of their own, a group that includes renters and people in multi-unit housing, a 2015 National Renewable Energy Laboratory analysis found.
• About 32 million U.S. households lived in apartment buildings in 2020, according to the federal Residential Energy Consumption Survey.
• Holu Hou Energy says HoluPower 3.0 is built from modular stacks, with storage set anywhere from 0kWh to 56kWh for each resident.
• The battery plugs into the company's EnergyCluster platform, which Holu Hou says already operates across more than 1,500 housing units.
• The company plans to install over 3,000 HoluPower 3.0 systems in multi-dwelling properties it develops itself over the next 3 years.

Why has solar for apartment buildings been so rare?

Most of the people solar has left out live where they do not control a roof. A 2015 analysis by the National Renewable Energy Laboratory found that roughly 49% of U.S. households were unable to host a photovoltaic system once renters, residents without roof access such as those in multi-unit buildings, and homes with too little sunny roof space are counted out.

That group is large. The U.S. Energy Information Administration's 2020 Residential Energy Consumption Survey counted 22.84 million households in buildings of five or more apartments and 9.34 million in buildings of two to four, out of 123.53 million homes. Each household in a large apartment building used 33.7 million Btu of energy that year, about a third of the 94.6 million Btu used in a detached single-family house.

Holu Hou Energy says buildings with separately metered units face their own obstacles: each apartment uses little power, its use swings from hour to hour, and in rentals the tenants keep changing. The company says those factors have made it close to impossible to install and finance panels for individual units, leaving the segment with almost no solar.

How does sharing solar inside one building work?

Under Holu Hou's design, power moves between neighbors before it leaves the building. When one unit's panels make more electricity than that home is using, the company says the surplus goes to other units in the same cluster rather than being curtailed or sold to the grid for little or nothing.

According to the company, that sharing does three things:

• It keeps the value of the solar power at the retail rate the owner would otherwise pay the utility.
• It means each home needs fewer kilowatt hours of battery.
• It evens out the effect of vacancies, residents away on vacation and changing daily routines.

Holu Hou says a cluster can also send power to the grid on command when it is enrolled in a virtual power plant, and keep residents supplied during a utility outage. For how energy security is shaping the wider shift in power supply, see our report on Wood Mackenzie's 2026 energy transition outlook.

What is new in HoluPower 3.0?

HoluPower 3.0 is the storage half of the system, built as stacked modules so a property can choose how much battery each home gets. The company says the modular design gives the lowest added cost per unit of storage in the solar industry, lowering the price of putting solar and storage on multi-dwelling properties.

Holu Hou says the product is already running in several of its clusters, meets the major U.S. certifications, complies with FCC rules and was designed to protect residents' and utilities' data. It adds that EnergyCluster has been in commercial operation, and shown to be bankable, for more than 5 years. Our overview of innovations in renewable energy covers other solar technology designed to fit onto buildings.

What does it mean for apartment owners and renters?

Our analysis: the release is aimed at the people who own and finance apartment buildings, and its pitch is that the same building-wide sharing makes solar pencil out where single-unit systems would not. Holu Hou puts multi-dwelling housing at about 50 million U.S. residential units, roughly a third of the housing stock; that is a count of homes, where the EIA survey above counts the households living in them. The company estimates the market it can serve at more than $250 billion. It says the strongest cases are places that combine high electricity rates, summer peak or time-of-use pricing, demand charges, frequent outages and virtual power plant programs.

For the people living in those buildings, the company says the payoff is access to lower electricity rates, backup power during outages and a part in virtual power plant programs.

Frequently asked questions

What is HoluPower 3.0?

HoluPower 3.0 is a modular solar battery from Holu Hou Energy for multi-unit residential buildings, with storage the company says can be set from 0kWh to 56kWh per resident.

Who is HoluPower 3.0 meant for?

Holu Hou Energy pitches the system to investors and owners of multi-dwelling residential properties who want renewable energy for their buildings and lower electricity rates for residents.

Is HoluPower 3.0 already installed anywhere?

Holu Hou says the battery is in commercial operation across multiple EnergyClusters, and that it will add over 3,000 systems in its own multi-dwelling properties over the next 3 years.

Can a building's solar keep running during a power outage?

The company says an EnergyCluster can supply residents when utility power is out, and can export power on command when it is enrolled in a virtual power plant.

Sources

• HoluPower 3.0 announcement: press release from Holu Hou Energy via GlobeNewswire, 10 November 2026.
• Shared Solar: Current Landscape, Market Potential, and the Impact of Federal Securities Regulation: research highlights from the National Renewable Energy Laboratory.
• Residential Energy Consumption Survey 2020, table CE1.1: energy use by housing type, from the U.S. Energy Information Administration.
• Holu Hou Energy: the company's website.