10 Best Portable Car Heater 2025 in the United States

The Mr. Heater 18,000 BTU Big Buddy Pro Series is a portable propane heater designed to warm spaces up to 450 square feet, making it quite powerful for use in cars, small garages, or outdoor areas. It uses a radiant heating method, which efficiently transfers heat and warms up quickly. The heater offers three heat settings—low, medium, and high—allowing you to control the temperature comfortably. One of its major advantages is safety: it has features like automatic shut-off if tipped over, if the pilot light goes out, or if low oxygen levels are detected, which is especially important for indoor or enclosed spaces. This makes it safer than many other propane heaters in its class.

The unit weighs about 11 pounds and has a pedestal design, making it reasonably portable though not pocket-sized. It runs on a propane tank (not included), so you'll need to keep fuel on hand. Some models do not have a built-in fan due to recent changes, so heat distribution relies on natural convection, which might feel less even in larger or drafty spaces. The heater operates quietly, which is a plus for use inside vehicles or small rooms. It may shut off at high altitudes above 7,000 feet, an important consideration for users in mountainous areas.

This heater represents a reliable and portable propane heating solution with strong safety features and good heating power. It is best suited for medium-sized spaces rather than very compact or extensive areas.

The Mr. Heater 18,000 BTU Portable Propane Big Buddy Heater is a strong candidate for anyone needing a portable heating solution, especially for outdoor or semi-enclosed spaces like a car or small workshop. It offers three heat settings—4,000, 9,000, and 18,000 BTU—allowing you to adjust warmth depending on your needs, and can effectively heat areas up to 450 square feet. This radiant heater uses propane, which makes it independent of electrical outlets, a handy feature when on the go or in remote locations. Weighing about 15 pounds and with a compact size, it is fairly portable, though not pocket-sized. Safety is well covered with automatic shut-offs if oxygen levels get too low or if the heater tips over, which is crucial for indoor or vehicle use.

The heater runs quietly, which is a plus for comfort. One limitation is that unauthorized accessories are not allowed, which might restrict some custom setups. This heater suits users wanting reliable, powerful heating while camping, working outdoors, or warming a vehicle area, but it’s essential to use it with proper ventilation and care since it is designed primarily for outdoor use and caution is needed in confined spaces to avoid risks associated with propane fumes or carbon monoxide.

The Saihisday 12V Car Auxiliary Heater is a compact, underdash device designed to help warm up your car and clear foggy or icy windshields during winter. It runs on your car’s 12V power supply, making it convenient for vehicles without complex setups. Its key strength is the 4-port vent system, which spreads warm air efficiently to multiple areas, acting as a heater, demister, and defroster. The blower motor provides noticeable warmth, though it may not be suited for very large vehicles or extremely cold conditions.

In terms of portability, it is compact enough to fit under the dash without taking much space, but it weighs nearly 7 pounds, so it’s not something you’ll want to move around regularly once installed. Installation requires connecting water hoses and wiring according to instructions, which might be a bit technical if you’re not familiar with car electronics or plumbing. The unit is well-rated by users (4 out of 5 stars), indicating decent reliability and performance, especially for those looking for an affordable way to boost cabin heat and defrost capability without replacing the main heating system.

This heater is a practical choice if you need extra warmth in your car during winter and are comfortable with a bit of installation effort. For users seeking a plug-and-play model or strong heat for very cold climates, exploring other options could be beneficial.