To run a space heater, choose a power station with a continuous AC output that meets or exceeds your heater’s wattage and enough battery capacity (Wh) for your desired runtime. For example, a 1,500W space heater requires at least 1,500W of continuous AC output.
The right power station also depends on how long you plan to run your heater and whether you need to power other devices at the same time. This guide explains how to calculate the capacity you need and choose a power station that meets your heating requirements.
The size of the power station you need depends on two key factors: your space heater's wattage and how many hours you want to run it. You also need to ensure the power station's continuous AC output is high enough to support the heater.
As a general guide, the table below shows the estimated battery capacity needed for different space heater wattages and heating durations, assuming 85% inverter efficiency and a 10% battery reserve.
These figures are estimated battery capacities, not guaranteed runtimes. Actual performance depends on the power station, inverter efficiency and the heater's actual electricity consumption.
For example, a 1,500W space heater running for four hours would require approximately 7,843Wh of rated battery capacity under these assumptions. The power station would also need at least 1,500W of continuous AC output to operate the heater.
If you only need to heat a small room for a short period, a smaller power station may be sufficient. However, for longer heating sessions or higher-wattage heaters, you'll need considerably more battery capacity.
Before choosing a power station, check how many watts your space heater uses. You can usually find this information on the heater's rating label, user manual or manufacturer's product page.
Most portable electric space heaters have a power rating between 500W and 1,500W. Some models also offer multiple heat settings, allowing you to reduce electricity consumption when full heating power isn't needed.
Here's what to look for:
- 500W–750W: Lower-power heaters, often suitable for smaller spaces or supplemental heating.
- 1,000W: A medium-power setting that provides more heat but requires greater power station output.
- 1,500W: A common maximum setting for portable space heaters, requiring a power station capable of supplying at least 1,500W continuously.
A power station's continuous AC output tells you how much power it can deliver to connected appliances at any given time. This is different from battery capacity, which determines how much energy it can store.
For example, if your space heater draws 1,500W, your power station needs a continuous AC output of at least 1,500W. A power station with a 1,000W continuous output cannot safely or reliably operate that heater at its full setting, even if it has a large 3,000Wh battery.
Also, don't confuse continuous output with peak or surge output. Peak output is a temporary rating and should not be used to determine whether a power station can operate a heater continuously.
Tip: Always check the heater's actual wattage at the setting you intend to use and compare it with the power station's rated continuous AC output. Allow some additional headroom where practical, and follow the manufacturer's operating limits.
Once you've checked that a power station has sufficient continuous AC output, the next step is choosing the right battery capacity. Battery capacity, measured in watt-hours (Wh), determines how much energy the power station can store and how long it can supply electricity to your space heater.
To estimate the capacity you need, multiply your heater's wattage by the number of hours you want to run it. Then account for energy lost during AC conversion and the battery reserve you want to maintain.
Use this formula:
Required battery capacity (Wh) = (Heater wattage × Operating hours) ÷ (Inverter efficiency × Usable battery fraction)
For example, assuming 85% inverter efficiency and 90% usable battery capacity, running a 1,000W space heater for two hours would require approximately 2,614Wh of rated battery capacity.
A power station cannot deliver all its stored battery energy to an AC appliance. Some energy is lost when converting DC battery power into AC electricity, and manufacturers may also limit how much of the battery capacity is available for use.
That's why it's important to allow for inverter losses and a battery reserve rather than choosing a power station based only on the heater's wattage.
If you plan to run other appliances at the same time, include their power consumption in your calculation as well. This will help you choose a power station with enough capacity for your overall electricity needs.
Choosing the right power station involves more than matching its wattage and battery capacity to your space heater. A few additional features can make a difference in how practical and versatile the unit is for everyday use.
Some portable power stations support additional battery packs, allowing you to increase total storage capacity as your needs change. This can be useful if you want to run a space heater for longer periods or power other appliances without replacing your original unit.
If you plan to run a space heater alongside a laptop, phone charger, lights or other devices, remember to account for their combined power consumption. The power station must have enough continuous AC output to handle the total load, as well as sufficient battery capacity to supply all connected devices.
Consider how quickly the power station can recharge and which charging options it supports. Many models can recharge through a wall outlet, while some also support solar panels or vehicle charging. Faster recharging can be particularly useful if you rely on the power station regularly.
Larger battery capacities generally mean heavier and bulkier power stations. If you plan to move the unit between rooms or take it camping, consider whether its weight and dimensions are practical for your needs. A larger model may offer more capacity, but it isn't necessarily the most convenient choice.
Yes, a portable power station can run a space heater overnight, but it requires substantial battery capacity and sufficient continuous AC output. The higher the heater's wattage and the longer it operates, the more battery capacity you'll need.
For example, running a 1,500W space heater for eight hours would require approximately 15,686Wh of rated battery capacity, assuming 85% inverter efficiency and 90% usable battery capacity. This is considerably more capacity than most standard portable power stations offer.
Using a lower-wattage heater or a reduced heat setting can help decrease energy consumption, although actual power use depends on the heater's operating cycle and thermostat.
Keep in mind that portable power stations are not necessarily designed for continuous overnight heating. Check the manufacturer's operating instructions, ensure adequate ventilation around the equipment and follow the space heater manufacturer's safety guidance. Never leave a portable space heater operating unattended or while sleeping unless its manufacturer explicitly permits that use.
For a closer look at how long different power stations can keep a space heater running, explore our guide: How Long Can a Portable Power Station Run a Space Heater? (With Runtime Examples).
Choosing the right power station for a space heater comes down to matching the heater's wattage with sufficient continuous AC output and choosing enough battery capacity for your desired heating time. While a smaller power station may work for a low-wattage heater or shorter heating sessions, higher-wattage models and longer operating periods require considerably more battery capacity.
Before buying, check your space heater's power requirements, calculate your estimated energy needs and consider whether you'll also be running other appliances. Choosing a power station that meets these requirements will help ensure you have enough power when you need it.
