Is there a UPS for an entire house?
There is. A RoseWater HUB connects at the main electrical panel and behaves like a UPS for everything on it, at a scale rack units can’t reach.
Most people know UPS units from the network closet. They are the boxes that beep when the power blinks and keep a router or server alive for a few minutes. Ask on an electrician forum about a UPS for the whole house and you’ll hear that true whole-house UPS systems are rare and specialized. That is accurate, and it is the gap RoseWater was built to fill. The company started by studying how mission-critical facilities keep their power clean and brought that design into homes.
| Rack UPS | Home battery (ESS) | RoseWater HUB | |
|---|---|---|---|
| Where it sits | One rack or closet | Behind a transfer switch at the panel | In line at the panel |
| Conditions power daily | Usually, for that rack | No, waits in standby | Yes, every circuit it serves |
| Transfer time | Short or none, depending on type | A switchover when the grid fails | Zero |
| Run time | Minutes | Hours, depending on size | Hours, sized in a Power Plan |
| Scale | One rack | Varies | 20 kW, 40 kW or 30 to 75 kVA three-phase |
What is transfer time and why does it matter?
Transfer time is the gap between the moment the grid fails and the moment backup power takes over. It matters because modern equipment notices gaps that people don’t.
A standby generator leaves the house dark for about 10 to 30 seconds while it starts and its transfer switch moves the load. A storage battery behind a switch closes that gap a lot, but there is still a switchover. Lighting processors, network switches, theater processors, security panels and the control boards in appliances can reset, lose settings or lock up during even a brief interruption.
Zero transfer time means there is no switchover at all. The backup is already carrying the load. Chris Matthews, a principal at Acoustic Design Group in Scottsdale, described his RoseWater system this way: “we never know when it happens because our internet keeps running and our lights stay on.”
What is online double conversion?
Online double conversion means the system converts incoming AC power to DC, then rebuilds it as clean AC, every second of the day. Your equipment never runs directly on grid power.
- Grid or generator power enters the HUB.
- It is converted to DC, where the batteries also sit.
- Inverter modules rebuild it as a clean 120 V, 60 Hz sine wave with total harmonic distortion under 3%.
- When incoming power sags or fails, the batteries are already on the DC side, so the output does not change.
Many UPS products offer an “eco mode” that drops out of double conversion to save energy and passes grid power straight through until there is a problem. RoseWater HUBs have no eco mode. They stay online all the time. Each inverter module takes both AC and DC input, so the batteries engage only during sags while the conditioning never stops. See How It Works for the full picture.
How is a UPS different from a home battery (ESS)?
A UPS protects the power continuously, and a home battery stores energy for later. The labels get mixed up, but the jobs are different.
An energy storage system holds energy, often from solar, and waits behind a transfer switch. While the grid is up it does not condition anything. A traditional UPS sits in the power path and conditions as it goes, but it is sized for minutes, not hours. RoseWater describes the HUB as neither one. It is continuous conditioning and long-duration standby storage in a single system.
There is also a permitting angle. Some towns treat any large battery as a lithium energy storage system. The HUB uses advanced lead-acid batteries, which RoseWater says can mean less regulatory friction. Our battery chemistry guide explains why.
How long can a whole house UPS run?
A RoseWater HUB runs for hours, with the exact figure set by your loads and battery size. Rack UPS units, by contrast, typically hold minutes.
The HUB20 and HUB40 start with 28.8 kWh of storage. Extended battery packs take a HUB20 to 86.4 kWh and a HUB40 to 172 kWh, and 3-Phase systems are sized per project. Run time is calculated in your Power Plan from the systems you choose. For outages longer than the battery, a generator behind the HUB extends it, and the HUB keeps conditioning the generator’s power.
What RoseWater does differently
RoseWater designed the HUB around redundancy. There are as few single points of failure as possible, critical parts are hot-swappable from the front without putting the system into bypass, and the cabinet is seismic-rated. Built-in monitoring lets the owner, the dealer and RoseWater see outages, voltage changes and energy data, and alerts can go to all three. RoseWater’s own technicians handle delivery and commissioning, and commissioning by RoseWater-trained personnel is part of the three-year warranty.
Getting started
The first step is deciding what the HUB should carry. Our Power Plan tool takes a few minutes. We design the system around your list, coordinate the panel work with your licensed electrician and RoseWater’s team, integrate it with your home’s control system and support it afterward. You can compare the options on our comparison page or contact us with questions.
