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UPS battery backup

Minutes: ride through a flicker, or shut down cleanly.

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Portable power stations

Hours: a charged battery, with no fuel to store.

33 guides

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Portable generators

Days: as long as the fuel lasts, always outdoors.

57 guides

Best picks and comparisons

Start here

UPS battery backup

Minutes: ride through a flicker, or shut down cleanly.

Portable power stations

Hours: a charged battery, with no fuel to store.

Portable generators

Days: as long as the fuel lasts, always outdoors.

Guide 20 · UPS

Choosing a Battery Backup (UPS) for a Gas Boiler and Circulator Pump

Choose a pure sine wave UPS sized from your boiler's own nameplate or a watt meter reading. Then confirm the runtime on the maker's chart at that load. Plan the hookup with a licensed electrician before you buy, because many boilers are hardwired.

Updated Drafted and checked with AIFact-checked by the HoldBackup editorial team How this guide was madeBased on manufacturer specs and owner reports, not HoldBackup's own testing.

On this page
  1. Why a gas boiler stops in an outage
  2. Pick pure sine wave output
  3. Size the UPS from your own numbers
  4. Connecting the boiler safely
  5. When a UPS is not enough
  6. Sources

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The verdict

Buy a pure sine wave UPS like the CyberPower CP1500PFCLCD, but first confirm that its runtime at your boiler's measured load covers the outage length you care about.

See the store link

What we check

  • Pure sine wave output
  • Capacity above your boiler's measured load
  • Runtime at your load on the maker's chart
  • A safe way to connect a hardwired boiler
  • Option for added battery capacity
  • Battery replacement and warranty terms
Compact tower UPS: upright unit on small feet with a narrow front display strip, a lit round power button and two vent slots on its side

Drawing of backup power equipment.

Store link UPS

CyberPower CP1500PFCLCD PFC Sinewave UPS Battery Backup and Surge Protector

One listing to compare. Check its specs against the list above before you buy.

Maker's US pageCyberPower's US page lists it with Purchase Online.cyberpowersystems.com Checked

What owners reportOwners report it works with home server and NAS shutdown software and lasts for years with fresh batteries. Forum owners also say the batteries can give out with no warning from the unit.TrueNAS forum, Unraid forum, The FPS Review forum Checked

PriceAmazon sets it, and it changes. The button takes you to today's price.

Store linkPaid link

The unit named above, on Amazon.

Check price on Amazon

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Why a gas boiler stops in an outage

A gas boiler burns gas, but it needs electricity to run. The control board, the ignition, the gas valve, and the circulator pump that moves hot water through your radiators or baseboard all run on power. Many boilers also have a power vent or inducer fan. When the power goes out, the boiler shuts down and stays off.

The electrical load is usually modest compared with a furnace blower or a well pump, which is why a UPS can carry it for a while. How long depends on your boiler's actual draw and on the battery. Only your own numbers will tell you that.

Pick pure sine wave output

A UPS makes AC power from its battery in one of two ways. Simulated or stepped sine wave output is cheaper. Pure sine wave output follows the smooth waveform of grid power. Circulator pump motors and electronic boiler controls are the kind of loads that can run hot, hum, or fault on stepped output.

Check your boiler's installation manual for any stated power requirement. Some makers say what kind of backup power they support. The listing on this page has sine wave in its name, so it fits this rule. Still confirm on the spec sheet that the output is sine wave whenever it runs on battery, not only when it passes grid power through.

Size the UPS from your own numbers

Do not guess your boiler's draw. Look at the rating plate on the boiler and the label on the circulator pump. These usually list volts and amps. Multiply them to get a rough upper bound in watts. If your boiler connects by a cord, a plug-in watt meter shows what it really draws while the burner and pump run.

For example, if your watt meter shows a steady reading while the boiler fires, use that number. Then check that the UPS's watt rating, not just its VA rating, sits comfortably above it. Motors draw a brief surge when they start, so leave headroom rather than sizing right at the limit.

Next, open the maker's runtime chart and find the runtime at your load. The boiler cycles on and off, so actual runtime over a cold night can be longer than the chart's figure for a constant load. Do not plan on that until you have seen it in your own home.

  • Read volts and amps from the boiler and pump labels
  • Measure with a plug-in watt meter if the boiler has a cord
  • Compare against the UPS watt rating, not only VA
  • Leave headroom for pump startup surge
  • Read runtime at your load on the maker's chart

Connecting the boiler safely

Many boilers are hardwired to a dedicated circuit with a service switch, with no plug to put into a UPS. Do not cut in a cord or improvise a connection yourself. Ask a licensed electrician what is allowed for your boiler and your local code, and how to wire it so a UPS can feed it.

Keep the UPS on a dry surface near the boiler and away from water lines and the flue. Leave room around it for airflow, and keep the battery where you can reach it for replacement.

When a UPS is not enough

A UPS is built to bridge short outages and ride through flickers. If your area sees outages that last many hours or days, a generator with a transfer switch or interlock installed by a licensed electrician is the better fit. Never run a generator indoors, in a garage, or near windows, because of carbon monoxide.

Check whether the UPS you choose can take an external battery pack. Some models can and many cannot, and the spec sheet will say so.

Sources

Recorded AI check: Oct 5, 2026. The sources below may include later additions. AI checks compare factual numbers and checkable claims with web sources; they do not verify every statement.

Best UPS battery backup for a home and APC vs CyberPower compare units from the makers' numbers. Every guide in this class is in UPS battery backup.

How this guide was made

  1. Drafted and checked with AI. An AI model wrote the draft from the guide's topic. A second AI pass looked for factual numbers to check against web sources. This does not verify every statement. A draft that fails the check is held for review.
  2. Fact-checked by the HoldBackup editorial team. On , a person on the HoldBackup editorial team reviewed this guide against its sources. That is a review of the writing, not a test of any unit.
  3. General guidance only. No prices, rankings, or test results, because we have none to back them. Check any number against the maker's own spec sheet.
  4. No lab tests, and we say so. HoldBackup has not run any unit named here.
  5. The store link is not a pick for this guide. It goes to a unit in this product class that this guide does not review. Check it against the list above before you buy.
  6. Labelled store links. A store button goes straight to Amazon with HoldBackup's affiliate tag. HoldBackup counts the click. A live button carries a "paid link" label, and the disclosure sits above the first one on every guide.

Questions

Can a UPS keep my gas boiler heating through a long outage?

Only for as long as its battery lasts at your boiler's load. Check the maker's runtime chart at your measured draw. For outages lasting many hours or days, a generator connected through an electrician-installed transfer switch or interlock is the better tool.

Why does sine wave output matter for a boiler?

Circulator pump motors and electronic boiler controls can misbehave on stepped or simulated sine output. Pure sine wave output matches grid power, so it is the safer choice. Also check your boiler's manual for any stated power requirement.

My boiler has no plug. Can I still use a UPS?

Possibly, but the connection must be done properly. Ask a licensed electrician how your boiler can be safely connected to a UPS under your local code. Do not modify the wiring yourself.

How do I find out how much power my boiler uses?

Read the volts and amps on the boiler's rating plate and the circulator pump's label. If the boiler plugs in, a plug-in watt meter gives you the real draw while it fires.

Where does the price button go?

Straight to Amazon. Amazon sets the price and availability, and both can change.

More guides

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    Can a Portable Power Station Run a Gas Furnace Blower During an Outage?

    How to tell if a portable power station can run your gas furnace in an outage: blower load, startup surge, runtime math, and safe hookup.

  2. Generator

    Can a Portable Generator Run a Tankless Gas Water Heater?

    Most tankless gas water heaters need electricity only for controls, igniter, and fan. Here is how to size a generator and connect it safely.

  3. Generator

    Can a Portable Generator Run an Electric Water Heater?

    Read your water heater's data plate, then match a generator's running watts and voltage. How to size it, connect it safely, and run it in shifts.

  4. Generator

    Running a Furnace Blower on a Portable Generator

    How to size and connect a portable generator to run a gas furnace blower during a winter outage, plus the wiring and carbon monoxide rules that apply.

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