UnderWarmer.com is a leading provider of innovative, reliable cold-weather solutions designed to keep you warm and active in the harshest conditions. Specializing in heated apparel, our flagship product, the UnderWarmer heated body warmer shirt, features built-in air-activated heat packs that deliver up to 12 hours of consistent warmth. Crafted for outdoor enthusiasts, workers, and adventurers, our lightweight and comfortable design prevents core cooling, helping to avoid those icy extremities long before they set in. Renowned for quality and affordability, UnderWarmer has established a trusted reputation among outdoor professionals and cold-weather athletes alike. We are committed to delivering durable, easy-to-use products backed by excellent customer service, including satisfaction guarantees and prompt support. Our mission is to provide effective, innovative heating solutions that empower you to enjoy your activities outdoors, regardless of the temperature. Choose UnderWarmer to stay warm, active, and confident—anytime, anywhere.

Shipping Policy

Enjoy free shipping on all orders exceeding $25.

Duration of Warmth

The UnderWarmer is a compression-fit body warmer that contains eight large air-activated heat packs, providing up to 12 hours of warmth.