Guide: insulation

Choosing the right shoes based on temperature, activity, and usage is now easier thanks to our insulation rating system. This guide helps you understand what the different levels mean and how to select the right shoe for your needs.

Three insulation levels

Our system for grading insulation in our shoes is divided into three levels: Warm, Warmer, and Warmest. The insulation rating is based on testing according to SATRA TM436:2010 — an industry standard used to determine insulation performance and cold classification for footwear.

However, how warm a shoe feels in practice also depends on factors such as activity level, shoe construction, circulation, cold sensitivity, and personal preference, so temperature ranges should be seen as guidance rather than absolute rules.

Shoes graded as warm

Warm: A good choice when you stay active or want a shoe that works across large parts of the year.

Comfort range: +10 °C to –15 °C

Season: 3-season use

Best suited for: Cool temperatures + low activity in mild cold + higher activity in colder weather.

Shoes graded as warmer

Warmer: Balances insulation and ventilation, suitable for spending longer periods outdoors in winter conditions.

Comfort range: +5 °C to –20 °C

Season: Winter

Best suited for: Cold winter days + moderate activity.

Shoes graded as warmest

Warmest: Developed for situations where warmth is critical, such as slow movement or standing still outdoors in cold weather.

Comfort range: 0 °C to –30 °C

Season: Winter

Best suited for: Very cold conditions + low activity or standing still.

What affects how warm a shoe feels?

Activity level

The more you move, the more heat your body generates.

– Low activity requires more insulation.

– High activity can manage with less insulation.

Fit and construction

How the shoe fits affects insulation performance.

– A fit that is too tight can compress insulation.

– A fit that is too loose can create unnecessary air circulation.

Moisture and ventilation

Moisture reduces insulation performance. Shoes that effectively manage moisture retain warmth better over time, especially during extended use.

Socks

The right socks make a big difference. Wool, especially merino wool, insulates even when damp and helps regulate temperature.

Outsole insulation properties

Cold often comes from the ground, but rubber naturally insulates against cold, and EVA midsoles trap air and help reduce heat loss.

We use our business to do good

At Icebug, we want to make really good shoes that help you get outside every day, no matter the weather or season. Our goal is to change the footwear industry by taking responsibility for our climate footprint. We make shoes that last, with low emissions and respect for both people and the planet. Part of what you invest in us, we give back to the Earth – for example by supporting organizations that protect old-growth forests.