Temperature Rating 101

How do quilt temperature ratings work? 

Quilt temperature ratings are determined using two industry standards: the EN (European Norm) and the ISO (International Organization for Standardization) test methods. These standardized systems are used to rate the warmth of sleeping bags and quilts, allowing you to compare insulation performance across different brands and models.

Both the EN and ISO methods provide three key temperature ratings:

• Comfort Rating – for cold sleepers

• Limit Rating – for average male sleepers

• Extreme Rating – for survival situations

These ratings help backpackers and campers choose the best quilt for their expected overnight temperatures.

EN/ISO Temperature Ratings Explained

The EN and ISO standards use three key temperature ratings to describe how warm a sleeping quilt or bag will keep you:

• Comfort Rating – The lowest temperature at which an average woman can sleep comfortably on her back.

• Lower Limit Rating – The lowest temperature at which an average man can sleep curled up without waking.

• Extreme Rating – The survival limit for an average woman; hypothermia risk is present, and it’s not intended for regular use.

All ratings are measured using a standardized setup: the test subject wears base layers, a hat, and lies on an insulated sleeping pad. This ensures consistent comparison between different quilt and sleeping bag models.

How does Enlightened Equipment rate their quilts and why does it matter to me? 

Enlightened Equipment ratings align with the EN lower limit standard. However, every situation is different, and you should consider your body and prior experience before deciding on a temperature rating.

If you are a woman or tend to sleep cold, consider buying a warmer quilt. Quilts also differ from sleeping bags in their lack of a hood and open nature. This means headgear is extremely important to maximize your comfort in a quilt. We recommend our Torrid Hood for maximal insulation. It is important to consider your entire sleep system when choosing a temperature rating. The shelter, pad, and layers you will use while sleeping can significantly affect your experience. If you're a newer quilt user, drafts may make your experience feel colder as you adjust or learn to use pad straps.

Dirty quilts may insulate poorly because of dirt impeding the loft. Other individual circumstances can further affect your sleep experience, such as under-eating, altitude, and temperature before sleeping. Read more tips about staying warm at night here.