Outages are a nuisance for all homes, but they are especially problematic for smart homes. Your router, modem, smart home hub, cameras, and network switches are small devices that sip electricity. But when the power flickers or goes out, the entire system can go down. The router reboots. The hub reconnects to devices. Cameras disappear from the network. Sometimes everything comes back normally, and sometimes you find yourself restarting half your setup.
A good uninterruptible power supply (UPS) fixes most of these problems. It keeps your network running during short outages and gives your equipment time to shut down cleanly during longer ones. If you’re building or improving a smart home, choosing the right UPS is one of the simplest upgrades you can make.
Table of Contents
Why Smart Homes Need a UPS
Many smart homes rely on a small set of core devices:
- modem
- router
- Wi-Fi access points
- network switches
- smart home hubs
- security camera systems
- sometimes a NAS or small server
None of these devices uses much power individually, but they all depend on each other. If your router goes down, the smart home hub may lose connectivity, cameras will stop recording, and automations will fail.
I live in an area where we experience outages every year. One of the biggest benefits of having UPS units on key devices is that I rarely have to touch anything when the power returns. The network stays up during short outages, and longer outages allow servers to shut down gracefully.
If you’re planning for reliability, it’s also worth thinking about outages in a broader sense. I wrote about this in my article on preparing your smart home for outages, where I walk through other steps that help keep systems running when the power fails.
A UPS is the foundation of that approach.
The Biggest UPS Sizing Mistake
Most people choose a UPS based only on wattage. They calculate how much power their equipment uses and then buy a UPS that barely covers that number. This usually works, but it often leads to disappointing runtime.
The better approach is to size a UPS based on the runtime you want, not just the wattage your devices draw. Smart home networking equipment usually consumes very little power. What you actually want is enough battery capacity to keep things running for a while.
A larger UPS will often provide:
- longer runtime
- fewer battery cycles
- more stable voltage
- longer battery life
For many smart home setups, choosing a slightly larger UPS than strictly necessary makes the system far more useful.
How Much Power Smart Home Devices Use
Networking gear tends to be surprisingly efficient. Most smart home infrastructure draws very little electricity compared to typical household appliances.
Here are common power ranges for the devices most people run in a smart home.
| Device | Typical Power Draw |
|---|---|
| Cable / Fiber Modem | 8–12 watts |
| Router | 10–15 watts |
| Wi-Fi Access Point | 8–12 watts |
| Smart Home Hub (Home Assistant, Hubitat, etc.) | 3–6 watts |
| Network Switch (unmanaged) | 10–25 watts |
| Security Camera Base Station / NVR | 10–30 watts |
| NAS | 20–60 watts depending on drives |
A small smart home network might only use 25–40 watts total. Even a more advanced setup with switches, cameras, and a NAS might stay under 100 watts.
Because the loads are small, runtime becomes the real differentiator between UPS models.
Example UPS Runtime for Smart Home Equipment
Once you know roughly how much power your equipment uses, you can estimate how long different UPS sizes will run.
The table below shows approximate runtimes for common smart home loads.
| UPS Size | 30W Load (Modem + Router) | 60W Load (Network + Hub) | 100W Load (Network + NAS) |
|---|---|---|---|
| 650VA | 40–60 minutes | 20–30 minutes | 10–15 minutes |
| 850VA | 60–90 minutes | 30–45 minutes | 15–25 minutes |
| 1000VA | 90–120 minutes | 45–60 minutes | 25–40 minutes |
| 1500VA | 2–3 hours | 1–1.5 hours | 45–70 minutes |
If you want to calculate this more precisely, many UPS manufacturers provide runtime calculators based on your device wattage.
These numbers vary by manufacturer and battery size, but they give a useful ballpark estimate. For most smart homes, a UPS in the 850–1000VA range provides a good balance of runtime and cost. It’s usually enough to keep your internet connection and smart home system running through short outages and brief power flickers.
Choosing the Right UPS Size
Here are three common scenarios and the UPS sizes that tend to work well.
Small setup: modem and router
Typical load: 20–30 watts
If your goal is simply to keep your internet connection alive during short outages, a UPS in the 600–850 VA range usually works well. These are compact and affordable. This size UPS for a router and modem can run for 30–60 minutes depending on the model.
Below are good entry-level units for protecting the most critical devices:
Medium setup: full network stack
Typical load: 40–80 watts
This scenario includes:
- modem
- router
- one or two Wi-Fi access points
- a network switch
- a smart home hub
For setups like this, a UPS in the 900–1000 VA range tends to work better. The extra battery capacity significantly increases runtime. Here are some good options
At this level you begin to get enough runtime to ride through many short outages without noticing them.
Advanced setup: network rack or NAS
Typical load: 80–150 watts
If you run additional equipment like:
- NAS systems
- camera recorders
- homelab servers
- rack-mounted networking gear
then moving up to a 1500 VA UPS is often the better choice.
This provides enough runtime to allow graceful shutdowns and gives your systems more time to recover if power returns quickly. Here are a couple of recommended models.
I have an earlier version of the CyberPower UPS for my primary router, network switch, and Proxmox virtualization hosts in my home lab.
Many of these models also include better monitoring features and USB connections for shutdown automation.
Additional Popular UPS Models
Below are popular models that others have bought at various price points and capacities:
Lithium vs Lead-Acid UPS
Most traditional UPS units use sealed lead-acid batteries. They are inexpensive and widely available, but they have a downside that many people eventually run into: the batteries degrade over time. After a few years, the runtime drops significantly and the batteries need to be replaced.
If you have several UPS units in your home, this replacement cycle can become annoying. Lithium-ion UPS models solve many of these problems. They tend to be:
- smaller
- lighter
- longer-lasting
- more tolerant of repeated charge cycles
Lithium units often cost more upfront, but for smaller networking loads they can be a great option because the batteries last much longer.
I eventually started switching some of my UPS units to lithium models for exactly this reason. I wrote more about that experience in my article on moving to lithium-ion UPSes.
In my own setup today, I often use lithium UPS units for smaller networking loads and keep lead-acid models for larger equipment where the cost difference is more significant. You can see the exact models I use in the article I referenced in the last paragraph. Below are some lithium ion UPSs you should consider for your smaller (modem, switch, router, surveillance camera) loads.
My Approach to UPS in a Smart Home
Over time I’ve settled on a simple approach. Critical networking equipment always sits behind a UPS. This includes routers, switches, and smart home hubs.
If an outage is short, the network stays online and everything continues working. If an outage lasts longer, the UPS provides enough time for servers or NAS systems to shut down safely.
The other benefit is convenience. When power returns, I’m not walking around the house rebooting devices or waiting for systems to reconnect. Everything simply comes back online.
Placement Tips
A few placement tips can help UPS units work better in smart home environments.
- First, place UPS units where your networking equipment already lives. This might be a network cabinet, structured wiring panel, or small rack.
- Second, avoid plugging high-power devices into the UPS battery outlets. Things like space heaters or large electronics can drain the battery quickly.
- Third, leave a little capacity headroom. A UPS that runs at 30–50 percent load will usually perform better than one operating near its limits.
Finally, remember that UPS units are not designed to power an entire house. Their job is to keep small but critical infrastructure running.
Final Thoughts
Smart homes depend on stable networks. When the power flickers, the weakest point is usually not the automation platform or the devices themselves. It’s the network equipment losing power.
A UPS is a relatively small investment that dramatically improves reliability. It keeps your internet connection alive during short outages, prevents unnecessary device reboots, and protects sensitive equipment.
For a smart home, it’s one of the most practical infrastructure upgrades you can make.
If you’re thinking about improving the reliability of your home network overall, UPS protection is just one part of the puzzle. I cover the full setup in The Home Network Manual.
What is your UPS strategy? Let me know in the comments or on Twitter.
