Skip to content
Back to Sunrun Blog
What Homeowners Need to Know About Uninterruptible Power Supply
SHARE TO SOCIAL MEDIA
Exploring uninterruptible power supply
As you explore different electricity solutions, you've no doubt come across the term "Uninterruptible Power Supply," often shortened to UPS. To help you decide on the right power backup for your home, it's crucial to understand the role a UPS plays. We'll break down what a UPS is, its advantages and limitations, and other alternatives to ensure you're protected during power loss.
What is an uninterruptible power supply (UPS)?
Put simply, a UPS is a back-up power supply that jumps into action the instant the main power source (like the utility grid) falters, whether it's a complete outage, a surge, or a sag. This near-instant switch is what makes a UPS essential for keeping mission critical applications and equipment running without interruption.1
Because of this seamless power transition, UPS units are vital in places where even a momentary loss of electricity can have serious consequences. Think IT facilities, data centers, hospitals, and banks. In these commercial settings, a UPS ensures a smooth shift to backup power or allows for a controlled shutdown of sensitive systems. While these large-scale industrial uses are well-known, there are still compelling reasons why you might want to consider the benefits of an uninterruptible power supply for your own home.2
How UPS systems work
So, how do UPS units actually work when the power goes out, keeping your essential devices running? Think of a UPS as a smart middleman that sits between your electronics and the wall outlet. Often resembling a compact box with outlets for multiple loads to connect, it does more than just distribute power. It's constantly monitoring the incoming electricity, ready to jump in the moment things get unstable – whether it's a total blackout, a sudden surge, or a voltage dip.
To understand how it makes power protection a reality, let's peek inside a battery-powered UPS:
The AC to DC Converter (Rectifier): This part takes the regular alternating current (AC) power from your wall and turns it into direct current (DC) power, which is what the battery uses to store energy. It also sends some of this DC energy directly to the next component.
The DC to AC Powerhouse (Inverter): This component does the opposite of the rectifier. It takes the DC energy – either from the rectifier during normal operation or from the battery during an outage – and converts it back into the AC energy that your computers, routers, and other devices need.
The Energy Tank (Batteries): This is the UPS's secret weapon! It stores DC energy so that when the AC energy goes out, the UPS can instantly provide its own juice to keep your equipment running. Good news: you can often replace these batteries without buying a whole new unit. They come in different types, like lead acid batteries, nickel-cadmium batteries, or the longer-lasting lithium ion batteries.
The Safety Switch (Static Bypass): Think of this as an emergency lane. If there’s a UPS failure, this switch can allow the regular AC energy to go straight to your connected devices, ensuring they still get power if possible.3
With all these parts working together, your UPS acts like a guardian for your electronics, providing surge protection for sensitive equipment and keeping them running when you need them most.
Which type of uninterrupted power supply is right for you?
So, which type of UPS is the right sidekick for your power needs? There are three main kinds you'll want to consider:
1. Standby UPS
A standby UPS is your straightforward power safety net. It waits patiently until it detects a power hiccup – a blackout, surge, or sag – then it instantly switches on its battery to keep your connected devices running. While it might not be a superhero against every power problem, it's a solid and budget-friendly choice for most homes, especially if you just want basic backup.
2. Line-interactive UPS
Think of this as the step up. In the same way as the standby, the line interactive UPS uses its battery for blackouts. But it also has a smart feature called an automatic voltage regulator (AVR) that smooths out those power spikes and dips, saving your equipment from getting fried without needing to drain the battery. This makes it a smart choice if you often see your lights flicker or have important gear you want to protect.
3. Double-conversion UPS
Also known as continuous, online or full-time UPS, choose a double conversion UPS if you want the ultimate power protection. Unlike the other two that have a tiny delay when switching to battery, a double-conversion UPS runs your equipment on battery power all the time. It constantly converts the incoming AC power to DC to charge the battery, then back to AC for your devices. This means zero interruption, no matter when the incoming utility power fails. Because of this seamless power, it's the go-to for industries dealing with super-critical data or sensitive gear – places where even a millisecond of downtime is a disaster.1,4 Just keep in mind, a double-conversion UPS is usually more expensive.
Benefits of a UPS
So, what's the upside of having an uninterruptible power supply (UPS) in your corner? Here are a few key wins:
Affordable security blanket: Think of a UPS as a reasonably priced insurance policy for your electronics. While the cost can change depending on the size and features, for most homes, it's a smart way to keep your essentials safe when the grid acts up.
Your gadget's bodyguard: Got some sensitive electronics you're always worrying about? Power surges and dips can fry sensitive tech. A UPS throws up an extra shield against that kind of damage, keeping your valuable devices safe and sound.
Peace of mind power: Losing power can be a real pain, whether it's losing important files, having your internet die, or worrying about your fancy TV, a UPS offers a simple solution. It's like a safety net for your advanced technology, giving you a reliable backup when the unexpected happens.
Limitations of a UPS
Short-term security: Think of UPS systems as a temporary energy bridge. It smoothly carries your sensitive electronics over a sudden power dip or short outage, but it's not designed for long journeys. Most baseline home UPS batteries will only keep things going for only a few minutes, maybe enough time to save your work or safely shut down. 3
Limited number of devices: Another thing to consider is that a standard UPS must have the devices it's supporting plugged in directly to the unit. It can also only supply power to a certain number of devices at once. So, if you've got a lot of things you want to keep running, you might need more than one UPS.
Not for the big stuff: When the power goes out, what are you really hoping stays on? For most homes, it's the big stuff like the fridge keeping your food fresh, or the AC keeping you cool. Now, while a UPS is a clever gadget, it's really designed for those delicate electronics that can't handle even a tiny blip in power – think computers where losing work isn't an option, or maybe some medical gear. The power-hungry appliances, though, like your oven, AC, or refrigerator, need a much bigger and longer-lasting power source, like a home battery connected to solar, or a generator. So, while a UPS has its specific uses, it's often not the right solution for those major home essentials during an outage.
They don't last forever: Finally, just like any tech, a UPS doesn't last forever. An uninterrupted power supply lasts 4 to 5 years on average. So, remember to plan for a replacement every few years to ensure you're always protected when the power goes out.4
Beyond UPS units: Power up with solar storage
While an uninterruptible power supply (UPS) is great for preserving unsaved work and protecting sensitive devices during brief power outages, it's really a short-term solution. For businesses, it ensures no electricity is lost before a backup generator kicks in. For homeowners, it buys you just enough time to save your work and properly shut down computers. But even though a UPS's runtime varies, it definitely won't keep your AC running, your refrigerators humming, or your TVs on during extended power loss.
What can handle longer power outages is a solar storage battery system. If you're considering a UPS, you'll almost certainly want to look at home battery storage as well. And for many who don't need a UPS, battery backup can be a fantastic upgrade to your home's power security. Systems like Tesla Powerwall 3 and the Franklin WH can provide near-instantaneous power when the grid goes down. For those with larger systems, more outage coverage can be achieved by adding multiple backup batteries. While sensitive electronics may be able to detect the transition, a homeowner would not notice the lights flicker.
Let's explore some of the main benefits of a solar energy system paired with battery backup.
Benefits of solar + battery
An extended power reserve: Just like a UPS, how long your battery keeps things running depends on what you're powering and how many batteries you have. A good rule of thumb is about an hour of power for every kWh of battery capacity.* Think of that Tesla Powerwall 3 with its 13.5 kWh – that's a good chunk of backup!6 Now, if you're running power-hungry stuff, that battery life will be shorter, maybe 20-25 minutes per kWh.†
Recharge ready, thanks to the sun: Here's where a home battery really shines with solar. Even during a blackout, if the sun's out, your panels will keep charging your battery. So, you use stored power at night, and then the sun refills it during the day – that cycle can keep going! Just remember, you'll want to pick and choose what's most important to power to make your stored energy last.
Powering your whole home (the smart way): Unlike a UPS that plugs into specific devices, a home battery sends power throughout your home using your existing electrical wiring – just like power from the grid. It sits tucked away in your garage or outside, but its energy is available everywhere, making it super simple compared to running power strips and extension cords from a UPS.
You're in control: With Sunrun's battery options, you get handy apps (from us and the manufacturer) that let you see what's going on. You can tweak settings, decide what gets powered, and check your battery levels – all from your phone!
Worry-free warranty: If you go with Sunrun for your battery backup, you're covered by a warranty for as long as you have your Sunrun subscription. That goes way beyond the standard manufacturer's battery warranty.**
The smarter power play: Solar battery power + UPS
UPS systems serve a specific purpose for short-term industrial needs whether it be surge protection or power stability. However, it's probably not the best long-term power security solution for your home. Whether you were considering a UPS or not, solar battery storage offers a far more comprehensive answer. For extended backup forget noisy, polluting motor generators – solar batteries offer energy efficiency, security, and real control for years to come. It's time to finally enjoy the peace of mind that comes with knowing your power – and your comfort – is protected, no matter what the grid throws your way.
Why homeowners choose Sunrun
With over 1 million customers, Sunrun tailors solutions to your home's specific needs. Our team of experts can guide you through the entire process, from the initial assessment to the installation and maintenance of your residential solar. With Sunrun, you can make your home more comfortable, environmentally friendly, and financially sustainable. Explore our plan options or get a free quote.
Sources:
1. https://www.nytimes.com/wirecutter/reviews/best-uninterruptible-power-supply-ups/
2.https://www.techtarget.com/searchdatacenter/definition/uninterruptible-power-supply
3. https://www.forbes.com/councils/forbestechcouncil/2022/10/04/the-new-significance-of-uninterruptible-power-supply-technology/
4. https://www.fs.com/blog/what-is-uninterruptible-power-supply-or-ups-8187.html
5. https://computer.howstuffworks.com/what-is-a-ups.htm
6. https://www.tesla.com/support/energy/powerwall/own/best-practices-during-power-outages?
7. https://www.tesla.com/support/energy/powerwall/learn/how-powerwall-works#:~:text=With%20Powerwall%203%20Expansion%20Powerwall%203%20Expansion,easily%20be%20installed%20with%20your%20Powerwall%203
*Based on the assumption of standard devices collectively using 1kWh per hour.
†Based on using one large heavy load at a time. A/C varies greatly on a number of factors such as unit size and cooling use. Estimate based on a 3 ton, 14 SEER unit running a 50% duty cycle. Using multiple heavy powered appliances simultaneously will reduce battery life. Note that spas, hot tubs, EV chargers, multiple A/C units, and other extremely heavy loads may not be able to be powered with one battery. Several hours
**Illinois customer warranties excluded