Before buying a battery-operated heater, decide what needs warming and where the heater will be used. Also consider whether to use rechargeable or disposable batteries.
Battery-operated heaters are better suited for warming small objects like hands or feet. They do not generate enough power to warm a large area or room. Although some radiators and space heaters are labelled as battery operated the battery often only powers the ignition and fan and not the heat.
Using gloves, socks or jackets with an added battery warmer is a way to get extra warmth for outdoor activities such as camping or skiing without adding extra layers. For longer periods of warmth, or when away from a power source, consider using disposable batteries. It is faster to swap flat batteries for new ones than to wait for rechargeable batteries to recharge.
Before buying a heater think about the design of the model. Some types connect the heater to the battery with a cable. Disposable batteries are often bulkier and heavier than rechargeable ones.