Smart & Connected Life Connected Car Tech 202 202 people found this article helpful Your Best Portable Car Heater Options by Jeremy Laukkonen Writer Jeremy Laukkonen is tech writer and the creator of a popular blog and video game startup. He also ghostwrites articles for numerous major trade publications. our editorial process Facebook Twitter LinkedIn Jeremy Laukkonen Updated on November 11, 2019 reviewed by Ryan Perian Lifewire Tech Review Board Member Ryan Perian is a certified IT specialist who holds numerous IT certifications and has 12+ years' experience working in the IT industry support and management positions. our review board Article reviewed on Jun 30, 2020 Ryan Perian Connected Car Tech Android Auto Apple CarPlay Navigation Tweet Share Email Some car heater cores are an absolute bear to replace, which can cause labor charges to go through the roof. Some mechanics might offer the option of just bypassing the heater core. It's not an ideal solution, but we can definitely sympathize with trying that option when an unexpected expense is dropped in your lap like that. There are other ways to work around the problem, too. If fixing the heater core on your car really isn't going to be possible before you start getting into cold weather, then a portable car heater is a viable option. However, there are a few things to keep in mind: Residential heaters (even portable ones) aren't always safe for automotive use.Although some propane heaters are (relatively) safe for indoor use, they should never be used in moving vehicles.A 12V portable car heater requires electricity to run, which may cause issues if you have a weak alternator or a lot of other accessories. What it comes down to is that while even the best electric car heater isn't going to replace your broken car heater, that doesn't mean you have to drive around icy cold. Residential Heaters as Portable Car Heaters Lifewire / Tim Liedtke Since residential space heaters are designed to heat up relatively large volumes of air, it stands to reason that you should be able to use one to heat up a car. And while it's true that virtually any space heater will put out enough heat to make you toasty warm in no time, there are two potential problems with this solution. Residential space heaters aren't designed for use in small, confined spaces. They typically come with warnings to keep flammable objects (i.e. your upholstery, etc.) 2 feet, 4 feet, or even further away from both the front and the back of the unit. Inside a car or truck, that typically isn't an option. So while you might be perfectly fine if you set up a space heater on the floor of your car, you do so at your own risk.The other issue with using a residential space heater is wattage. You'll need to install an inverter that puts out enough wattage to run the heater, and even then you could run into a situation where your alternator can't keep up with the demand. There's lots more to know about electric car heaters. Portable Propane Heaters Although some portable propane heaters are relatively safe to use indoors, these heaters come with the inherent risk of either fire or suffocation. Propane heaters that rely on an open flame should never be used in a car due to the danger of fire, and heaters that rely on incomplete combustion carry the risk of carbon monoxide poisoning. Portable propane heaters that are billed as being safe to use indoors typically include a safety valve that will trigger if the oxygen level becomes dangerously low. That makes them relatively safe to use indoors, but we still wouldn't recommend using one in your car while you're driving. Portable 12V Car Heaters The best, safest alternative to your factory heater is a 12V heater that's specifically designed for automotive use. However, you'll typically find that the ones that are designed to plug into your cigarette lighter won't put out enough heat. That's due to the fact that accessories that are plugged into the cigarette lighter receptacle can only draw so much amperage (typically 10 or 15 amps) without blowing a fuse. Larger 12V car heaters have to be wired directly to the battery (typically with an inline fuse for safety) in order to draw enough power to put out the kind of heat you need during the cold winter months. As to how well these heaters work is concerned, your mileage is going to vary. They typically don't put out as much heat as a factory heater, but if you temper your expectations, you shouldn't be too disappointed. Of course, you still have to think about how much power the heater is drawing. If your alternator isn't up to the task, you might be better off just saving up enough money to fix the problem right. The Bottom Line: Portable Car Heaters Aren't True Replacements The ugly truth is that while there are some portable car heater options that can get you by, depending on exactly what you expect out of such a device, no portable electric heater will ever truly replace your factory heating system. If money is an issue to the point where your heater core is prohibitively expensive to access and replace, then there are real car heater replacements that actually tap into your car or truck's cooling system, but they are both more expensive to purchase and require some actual installation work. On the other hand, if all you need to do is to take the chill off before or during your drive, then a space heater on a timer or a weak 12V heater may get you through the worst of the winter. Just make sure to bundle up first.