Routers and modems usually draw much less power than desktop PCs, which means even a modest battery backup can keep home internet alive for a useful amount of time. The trick is plugging in only the network gear that matters, estimating watts realistically, and understanding whether your ISP connection stays active during a local outage.
Quick Picks
| Pick | Best for | Why it stands out | Watch out for |
|---|---|---|---|
| APC BE600M1 | Best compact router UPS | Small, affordable battery backup with enough capacity for typical modem and router setups. | Limited runtime if you plug in extra devices. |
| APC BE850G2 | Best step-up home network UPS | More capacity and outlets for a router, modem, ONT, and small switch. | Larger than compact network-only units. |
| CyberPower CP900AVR | Best AVR option | Automatic voltage regulation can help in areas with brownouts or unstable power. | More UPS than a simple router-only setup may need. |
| CyberPower ST425 | Best budget short-outage pick | Simple standby UPS for keeping basic network gear alive through brief interruptions. | Lower capacity than larger models. |
| APC Back-UPS Connect BGE90M | Best mini network backup | Designed for low-power network gear where compact size matters. | Not meant for high-power desktop equipment. |
Our Picks in Detail
- Small, affordable battery backup with enough capacity for typical modem and router setups.
- Limited runtime if you plug in extra devices.
- More capacity and outlets for a router, modem, ONT, and small switch.
- Larger than compact network-only units.
- Automatic voltage regulation can help in areas with brownouts or unstable power.
- More UPS than a simple router-only setup may need.
- Simple standby UPS for keeping basic network gear alive through brief interruptions.
- Lower capacity than larger models.
- Designed for low-power network gear where compact size matters.
- Not meant for high-power desktop equipment.
What to Plug Into the UPS
For internet backup, plug in the modem or fiber ONT, the main router or mesh gateway, and any small switch required for the router path. Do not plug in TVs, desktop PCs, printers, speakers, or chargers unless you are intentionally reducing runtime.
Fiber homes need special attention because the ONT may be in a garage, utility room, closet, or outside enclosure. If the router has battery backup but the ONT does not, the internet may still go down.
How to Estimate Runtime
- Add device wattage: Many modem, router, and ONT combinations draw roughly 15 to 40 watts total.
- Leave battery headroom: UPS runtime estimates are best-case and batteries age over time.
- Use low-power gear only: Every extra device cuts runtime.
- Check alarm behavior: Some UPS units beep during outages unless silenced.
- Replace batteries: UPS batteries are consumables, not lifetime parts.
Best UPS Size by Setup
| Pick | Best for | Why it stands out | Watch out for |
|---|---|---|---|
| Cable modem plus router | 425VA to 650VA compact UPS | Enough for many short outages without taking much space. | Runtime varies by router power draw. |
| Fiber ONT plus router | UPS at ONT and router if separated | Both ends need power for internet to stay up. | Garage or utility-room placement may need temperature awareness. |
| Mesh gateway plus small switch | 650VA to 900VA UPS | More outlets and capacity give cleaner headroom. | Only back up the main gateway, not every satellite node. |
| Camera or alarm network | UPS plus PoE budget planning | Keeps core network and recorder alive longer. | PoE cameras can drain batteries quickly. |
Will Internet Stay Up During a Power Outage?
Sometimes yes, sometimes no. If the outage only affects your home or immediate building, a UPS can keep you online. If the provider equipment in your area loses power, the connection may drop even though your router is still running.
Cable, fiber, and fixed wireless networks handle outages differently. The best way to know is to test during a small outage or ask your provider how local backup power is handled.
How to Use This Page
Buy for the network gear you actually need alive. Put the UPS where the modem, router, or ONT gets power, label the backed-up outlets, and do a short unplug test when nobody is on an important call.
FAQ
How long will a UPS run a router and modem?
It depends on battery size and device wattage. Many small UPS units can keep basic network gear running for tens of minutes, while larger units can last longer if only low-power devices are connected.
Do I need pure sine wave for a router UPS?
Usually no. Most router and modem power bricks work fine with mainstream standby or line-interactive UPS units. Pure sine wave matters more for certain PCs and sensitive equipment.
Should I plug a laser printer into my UPS?
No. Laser printers draw large bursts of power and can overload or drain a UPS quickly.
Do I need separate UPS units for mesh nodes?
Usually only the main modem, ONT, router, or gateway needs backup for internet access. Extra mesh nodes need power only if you require coverage in those rooms during an outage.
Test Before and After You Upgrade
After setup, run a speed test, unplug the UPS from the wall for a few minutes, and confirm the network stays online. Then plug it back in and check that everything recovers cleanly.