Note: costs mentioned below are given in US dollars as a general point of reference — actual prices vary by country, currency, and local market.
A car emergency blanket should survive being crammed in a trunk through summer heat and winter cold for years, then work the one time you need it. Thin mylar/foil blankets cost $1-$5 and reflect up to 90% of body heat but tear easily and offer no insulation from wind; heavier fleece or wool car blankets cost $15-$40, are more durable and comfortable, and work better for extended roadside waits. For a glovebox or trunk kit, having both — a compact mylar blanket as backup and a sturdier fleece/wool blanket as primary — covers the most scenarios.
At a glance
| Type | Typical price / best use |
|---|---|
| Mylar/foil emergency blanket | $1-$5; compact backup, reflects body heat |
| Fleece car blanket | $15-$30; comfortable, durable, moderate warmth |
| Wool blanket | $25-$40+; warmest, heaviest, most durable |
| Packed size (mylar) | Fits in a glove box, palm-sized folded |
| Storage temperature tolerance | Most rated for wide range but check product specs |
Why every car should carry one
A breakdown or accident that strands you roadside in cold weather turns from an inconvenience into a real hazard within an hour or two, especially if the engine isn't running for heat. An emergency blanket is one of the cheapest, smallest items you can keep in a car that meaningfully reduces the risk of hypothermia while waiting for help, whether that's a tow truck or a family member.
Mylar (space) blankets
These thin, reflective foil blankets are designed to reflect radiated body heat back toward the wearer, and manufacturers commonly claim they reflect roughly 80-90% of that heat. They're extremely compact and cheap, making them easy to stash in a glove box, first-aid kit, or every seat pocket. The trade-off: they're thin, crinkly, tear easily, and provide little wind-blocking or cushioning compared to fabric blankets, so they work best as a heat-retention layer, not a comfort item.
Fleece and wool blankets
A proper fleece or wool blanket is bulkier to store but far more comfortable and durable for an extended wait — wrapping around the body, blocking wind better, and holding up to repeated use over years without tearing. Wool in particular retains significant insulating value even when damp, which matters if you're stranded in rain or snow. These are a better choice as the primary blanket in a trunk kit, with a compact mylar blanket as lightweight backup.
Storage considerations
A trunk sees far wider temperature swings than a house — well above 100°F (38°C) in a parked summer car and well below freezing in winter. Check that any emergency blanket is rated to tolerate that range without becoming brittle (some cheap mylar blankets degrade after repeated heat cycling) or losing loft (natural fibers like wool are generally fine, but cheap synthetic fill blankets can compress and lose insulating value over years of storage).
Not all "emergency blankets" sold cheaply online are genuinely reflective mylar — some are just thin plastic sheeting with no meaningful heat-reflective coating, so buy from a known brand or one with clear material specs. A blanket alone doesn't replace visibility gear — pair it with warning triangles or reflective gear if stopped on a roadside at night.
Building it into a full roadside kit
- Compact mylar blanket for glove box or personal bag
- Larger fleece or wool blanket in the trunk kit for extended waits or multiple occupants
- Pair with other cold-weather essentials: hand warmers, a flashlight, and warning triangles
- Check and refresh trunk-stored blankets every year or two for wear or degradation
Who needs this most
Drivers in cold-winter regions or those who regularly drive rural or low-traffic routes benefit most, since help can take longer to arrive. Even in milder climates, an emergency blanket is inexpensive enough that it's worth keeping in every vehicle as a low-cost insurance policy against an unexpected overnight breakdown or accident.
Frequently asked questions
Do mylar emergency blankets actually work?
How long do emergency blankets last in a car?
What's the best blanket to keep in a car for winter?
Can emergency blankets be reused?
Where should I store an emergency blanket in my car?
Sources & further reading
- Ready.gov — Build a Kit (Emergency Preparedness)
- National Weather Service — Cold Weather and Hypothermia Safety
Figures, prices and policy details were current at the last-updated date above. Automotive pricing, incentives and regulations change frequently — verify time-sensitive details with the linked primary sources. Read our editorial policy and fact-checking standards.
