What Is a Hammock Underquilt and How Do You Use One?

Overnighting in a hammock can get cold. Learn what an underquilt is, how to use one and your other options for staying warm.

If you’ve grown to love hanging out in your hammock, perhaps you’ve contemplated sleeping overnight in your outdoor cocoon. Two obvious needs for overnight comfort are bug netting and a rain tarp, which you can buy separately or may come included as parts of a hammock tent system. One often overlooked issue, though, is how you can stay warm when cold night air wafts across your backside.

The answer is an underquilt, which is simply an insulated quilt designed to hang underneath your hammock to prevent heat loss.

An underquilt solves a similar problem to sleeping on the ground in a tent. Your sleeping bag, whether it features lofty down fill or a premium synthetic insulation, compresses under your body weight, allowing the cold ground to conduct warmth away from your body. Your bag also compresses under you in a hammock, leading to convective heat loss from the cold night air stealing away body warmth.

A sleeping pad solves the heat-loss problem on the ground by creating an insulated air space underneath you. A pad can perform the same function in a hammock, but underquilts are specifically designed to fit certain hammock models, or you can find ones that can be adjusted to fit a wide range of hammocks.

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Underquilts vs. Sleeping Pads

If you’re trying to decide between an underquilt and a sleeping pad for staying warm in a hammock, consider the following points:

Underquilt pros

  • Won’t interfere with your naturally comfortable hammock sleeping position.
  • Models with high-loft fills can provide superior warmth.

Sleeping pad pros

  • Can be used in both a tent and a hammock, though the hammock fit can be less than ideal.
  • Available in models designed for use in hammocks for a better fit.
  • Air pads can be deflated slightly in a hammock for a better fit (too low, though, and you’ll have cold spots; too high and your setup can get a little tippy).

Warmth: Comparing the relative warmth between an underquilt and a sleeping pad is challenging. R-values (the system of measuring heat conductivity in a sleeping pad) can’t be calculated for underquilts, so that spec won’t help. An underquilt that fits well and has a premium, high-loft fill, though, will be hard to beat for warmth. Note, too, that unlike bags that have temperature ratings, no universally accepted warmth ratings are available for underquilts. If you’re looking to match the approximate warmth of your sleeping bag, a rough guideline is to get an underquilt of roughly the same thickness (loft) as your bag.

Weight: If you’re a backpacker, then weight will also be a concern. Pads and quilts are roughly comparable in weight, with the caveat that all the usual ounce-saving factors come into play: things like lighter fills and tapered designs, for example.

Cost: Comparing the relative expense between an underquilt and a sleeping pad depends entirely on the type of pad. A premium air pad can be comparable in price, while a closed-cell foam pad will be far less expensive. Most people already have a sleeping pad, too, so you can save cost initially by using that for overnight trips. If you then decide to fully embrace hammock camping, you can upgrade to an underquilt later.

How to Set Up a Hammock Underquilt

Each underquilt will come with instructions, so that’s your first source for fit recommendations. Below are some universal tips that will help you create the warmest possible setup for your underquilt:

  1. To prevent it from getting wet or dirty on the ground, lay the quilt inside the hammock to start; then attach the ends and remove enough slack so that it won’t touch the ground when you slide it out of and under the hammock.
  2. Minimize the air space between the hammock (with you in it) and the top of the quilt. Snug up the adjustments to ensure the quilt is super close, but not so close that your body compresses it.
  3. Snug each end tightly to prevent air from flowing through.
  4. Secure any attachments along the sides to prevent airflow gaps from forming there.

Budget Tips for Insulating Your Hammock

  • Sleeping pad wings: This hammock accessory fits onto your current rectangular sleeping pad and helps it resist shifting around in a hammock.
  • Buy and trim a closed-cell foam pad: You’ll have a custom-fit pad for your hammock; use two pads for added warmth.
  • DIY an underquilt from an old sleeping bag or quilt: This requires sewing skills and ingenuity.
  • An emergency blanket can serve as a summer-weight underquilt: Hang it below your hammock so its reflective material can radiate back some body heat. (Don’t place it inside the hammock, though, because you need a little space between you and the blanket.)

Learn More: How to Choose a Hammock