How to Hang an Underquilt

By topquilt.com · Updated Oct 21, 2026 · 6 min read

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An underquilt is only as warm as its fit. The same underquilt that keeps one person cozy at 20°F can leave another cold at 40°F simply because of a gap at the hips or a cord pulled too tight. This guide covers how to hang an underquilt step by step, how to adjust it once you're inside, and how to troubleshoot cold spots. If you're still choosing one, start with our underquilt guide.

How underquilt suspension works

Most underquilts hang from two attachment points, one at each end of the hammock. Shock cord runs through channels at the head and foot ends, gathering the fabric so the underquilt forms a cradle. Many also have shock cord along the long sides, letting you snug the edges up around your shoulders. For a deeper look at shock cord vs static line and side pull-outs, see underquilt suspension explained.

Common attachment styles:

• Clip to end channels: small carabiners or hooks clip to the hammock's gathered end or its continuous loops. The most common setup.
• Independent suspension lines: lines run to the hammock suspension or a ridgeline, with adjusters that let you slide the underquilt along the hammock.
• Integrated: some hammocks (often bridge or specialized designs) have dedicated underquilt attachment points.

Whatever your system, the adjustments are the same: height, position along the hammock, and side tension.

What you need

• Your hammock, hung with a reasonable sag (about a 30-degree angle at the suspension is a good start).
• The underquilt with its suspension and clips.
• Optional: a structural ridgeline, which keeps the hammock's sag consistent from night to night and makes underquilt adjustments repeatable. See ultralight hammock setup for ridgeline options, or pick up a pre-made adjustable ridgeline (check price on Amazon).

Step by step: hanging an underquilt

1. Hang the hammock. Get your sag right before touching the underquilt. Changing the hammock afterward means re-adjusting everything.
2. Identify the head end. Many underquilts have a marked head end, often wider or with a different cord color. On asymmetric designs this matters.
3. Clip on both ends. Attach the head-end clip near the hammock's head-end gather, and the foot-end clip near the foot-end gather. Keep the shock cord fully loose for now.
4. Center it. Slide the underquilt so its middle sits roughly under where your hips will be, slightly toward the head end on most hammocks, since your torso is heavier.
5. Snug the end cords. Tighten the head and foot shock cord channels until the underquilt rises to touch the empty hammock lightly. It should look like a shallow cradle, not a tight drum.
6. Snug the side cords. If your underquilt has side shock cord, tighten it until the edges wrap up toward the hammock's sides.
7. Get in. Lie in your normal diagonal position with your top quilt. The underquilt will sag and shift with your weight.
8. Feel for gaps. Run a hand down between the hammock and the underquilt along your sides, shoulders and hips. Any spot where you feel cool air or no contact is a gap.
9. Fine-tune from inside. Adjust the cords you can reach without getting out. Small changes make a big difference.
10. Re-check after 10 minutes. Down settles and the hammock fabric stretches a little. A quick final adjustment usually locks it in.

Getting the height right

Height is the most important adjustment and the most common problem.

Too low

If the underquilt hangs too low, there's an air gap between the hammock and the loft. Cold air circulates through it and you'll feel chilly no matter how warm the underquilt is rated. The giveaway: a cold patch you can feel with your hand, often under the hips or shoulders. Fix: tighten the end and side shock cords to raise it.

Too high

If the underquilt is pulled too tight, your body weight compresses the down against the taut fabric. Compressed down doesn't insulate, so you'll feel a cold patch right where you're heaviest, usually your butt. Fix: loosen the suspension slightly until the loft under you looks full when you're lying in the hammock.

Just right

The underquilt should touch the hammock everywhere you contact the fabric, with the loft gently pressed but not flattened. When you look from outside with someone lying in the hammock, you shouldn't see light between the two layers, and the underquilt should look plump, not thin.

Positioning for a diagonal lay

In a gathered-end hammock you lie diagonally, so your head is off to one side of the centerline and your feet are off to the other. A straight-cut underquilt needs to be wide enough to cover that diagonal, or shifted slightly to match it.

• If your shoulder on the head-end side feels cold, shift the head end of the underquilt toward that side.
• If your feet are cold on the opposite side, shift the foot end that way.
• If you can't cover both, consider a wider underquilt or one designed for asymmetric lays.

Some people tie a short length of cord between the underquilt's side and the hammock's side to hold it in a diagonal position.

Common gaps and how to fix them

For the classic "cold butt" problem in depth, read cold butt syndrome.

Hanging a 3/4 or partial underquilt

Shorter underquilts (see our best 3/4 underquilts) follow the same steps, with two differences. First, position matters more: center the 3/4 underquilt so it covers from your shoulders down past your knees. Second, plan what goes under your lower legs. A folded sit pad, a short piece of foam, or your empty backpack inside the hammock works. Some people find it easier to put a small pillow under their knees, which also improves comfort in a gathered-end hammock.

Wind and weather

A perfectly fitted underquilt still loses heat to wind. Pitch your tarp low on the windward side, use tarp doors in storms, and consider an underquilt protector or a full hammock sock. These also keep splash and spray off the underquilt in rain. We compare options in top covers and hammock socks. A larger tarp helps too; many hammockers carry an 11-12 foot tarp with doors for shoulder season (check price on Amazon).

When the fit changes overnight

An underquilt that fit perfectly at 9 p.m. can feel drafty by 3 a.m. Nylon hammock fabric stretches slightly under load, shock cord relaxes as it cools, and you shift position as you sleep. If you wake with a new cold spot, reach out and snug the nearest cord a little rather than getting out. Polyester hammock fabrics and non-stretch suspension reduce this drift, as does a structural ridgeline that holds the hammock's sag constant.

Leaving the underquilt attached

Many hammock campers never detach the underquilt. They pull a snakeskin (a long fabric sleeve) over the hammock and underquilt together, or stuff both into one sack. Next camp, hanging the hammock also hangs the underquilt in roughly the right place, and you just fine-tune. If you do this, take the underquilt out to loft for a few minutes before bed, and store it loose at home. See how to pack a quilt.

Pairing with your top quilt

Once your underquilt fits, your top quilt finishes the system. Make sure the top quilt's ratings roughly match, and that you know how to seal drafts at the shoulders. See how to use a top quilt in a hammock and the hammock top quilt guide. If you're shopping for either half, see best underquilts and best hammock top quilts.