How to Choose a Power Station for a Heater

A heater asks a station to do two things

A heater is one of the hardest loads you can connect to a portable power station. It draws power the whole time it is heating, without the pauses that most other devices have. That means a station must meet two conditions: it must list a continuous output high enough to feed the heater, and it must hold enough capacity, in watt-hours, for the heater to keep drawing energy. Most stations meet one condition better than the other.

The question has two listings to read. The heater's listing states its wattage, and that figure is the demand the station must meet. The station's listing states a continuous output in watts and a capacity in watt-hours. This article explains those figures and why a heater, more than most loads, asks the station to deliver a continuous high output.

Watts and watt-hours as listing words

Electricity is measured in units of power called watts, as the U.S. Energy Information Administration explains. A watt is a measure of power at a moment: how much electricity a device draws while it runs. A watt-hour is a measure of energy over time: how much electricity a device uses, or a station holds, across an hour. Read the two figures together to see what a listing is telling you.

On a power station listing, the watt figure is the continuous output, the power the station can deliver at any moment. The watt-hour figure is the capacity, the total energy the station holds. On a heater listing, the wattage is the power the heater draws while heating. Compare the heater's wattage with the station's continuous output first; the capacity is a separate figure that affects how long the heater runs.

Why a heater is a hard load

Most appliances you connect to a portable power station do not draw their peak power constantly. A fridge cycles on and off. A laptop settles to a low draw after startup. A light uses a steady but small amount. A heater does the opposite: it draws its full wattage for as long as it heats, then stops only when its thermostat reaches the set temperature. Between those moments, the load on the station is continuous and high.

That is why most portable stations cannot run a heater for long. A station's listing states a continuous output, and a heater is a continuous demand. If the heater's wattage is above the station's continuous output, the station cannot feed it at all. If the heater fits, the second limit is the capacity: the heater keeps drawing from the watt-hours until the station empties.

This article gives no runtime figures. The station's listing and the maker's page state what a model supports, and the heater's own listing states its wattage. Comparing those numbers tells you whether a heater can connect; a runtime figure is not something a listing carries.

Continuous output versus surge

A power station listing usually states a continuous output and may also state a surge or peak figure. The continuous output is the power the station can deliver steadily. The surge figure covers a brief, higher draw at the moment a device starts.

A heater does not need a surge. It starts at its full heating wattage and stays there. The continuous output is the figure to read for a heater. Some makers give a name to a temporary power-lifting feature; those names describe a short boost, not a steady output, and a heater is a steady load. Surge and continuous output are different figures.

• Continuous output: the power the station can deliver steadily; compare it with the heater's wattage.
• Surge or peak: a brief higher draw at startup; a heater does not need it, because it starts at full wattage.
• Capacity in watt-hours: the energy the station holds; the heater draws from it the whole time it heats.

Capacity is the second number

The capacity figure in a station's title, in watt-hours, is the energy the station holds. It is the second number that decides whether a heater can run, after the continuous output. Even a station that lists enough continuous output has a finite capacity, and the heater draws from it the whole time.

Larger stations, in the higher capacity bands on this site, are the ones that list both a high continuous output and a large capacity. That is why the guides group stations by capacity, and why a station chosen for a heater is usually a large station. The 2,000Wh-class guide and the 5,000Wh-class guide compare those bands on their stated details.

This site gives no runtime figure for a heater or any other appliance. That choice is explained here: a listing does not state runtime, so the site does not calculate it.

Read the heater's own listing

The heater's listing states its wattage. That is the number to bring to the power station listing. Compare it with the station's continuous output: the station must list a continuous output at least that high.

The heater's listing may also state its own energy figures. The reading that matters for choosing a station is the wattage, because it is the demand the station must meet. What a heater may be used in or near is the heater maker's guidance, not a power station question.

Read the maker's page next to the listing

A power station listing on this site carries what the seller states: capacity in watt-hours, continuous output in watts, battery chemistry, and whether a panel or an extra battery is in the bundle. It does not carry a runtime figure for a heater or any appliance.

The maker's own page, linked from the listing, is where a maker states what a model supports. Read that page for the continuous output and capacity in the maker's own words, and for any notes about high-draw loads. This site compared the listings on stated details; the maker's page is the place to read details the listing does not print.

What a listing cannot tell you

A listing cannot tell you how long a heater runs on a station. Runtime depends on the heater's wattage, the station's capacity, and the heater's own thermostat behavior, and no listing states that figure. This site compares listings on their stated details and gives no runtime.

A listing also cannot tell you where a heater may be used. That is the heater maker's question, answered in the heater's own documentation. The power station question is narrower: does the station list a continuous output and a capacity that match the heater's wattage? The home backup guide and the brand guides are places to compare how makers state those figures.

What to pick for your situation

Questions

Can a portable power station run a space heater?

Only if the station's listing states a continuous output at least as high as the heater's wattage, and even then the capacity, in watt-hours, limits how long it runs. No listing states a runtime figure, so compare the two stated numbers yourself and read the maker's page.

What does the wattage on a heater listing mean?

It is the power the heater draws while heating, in watts, as the U.S. Energy Information Administration explains. It is the demand the station must meet.

What is the difference between watts and watt-hours on a station listing?

The watt figure is the continuous output, the power the station can deliver at a moment. The watt-hour figure is the capacity, the total energy the station holds. A heater needs the first to be high enough and draws from the second the whole time it heats.

Why does this site give no runtime for a heater?

Because a listing does not state runtime for an appliance. Runtime depends on the heater's wattage, the station's capacity, and the heater's thermostat behavior. The site compares listings on their stated details only.

Should I read the maker's page before buying?

Yes. The maker's page states what a model supports in the maker's own words, including continuous output and capacity. Read it next to the listing.