Thermarest Sizing

How do I repair my Therm-a-Rest mattress and/or obtain warranty service?

Click here to download the Universal Therm-a-Rest Mattress Repair Instructions, including how to locate leaks and make repairs in the field or at home on any mattress model.

If you have further questions about repair or warranty, or would like to send your mattress to us for repair. In the U.S., please contact our Customer Service department at 1-800-531-9531. 

Should you find yourself without access to Therm-a-Rest Repair Kits, repairs can also be made using items commonly found at most outdoor gear shops. (Remember that for maximum effectiveness, ALL of the below repairs should begin with a clean and dry mattress. An alcohol swab is an ideal cleaner that dries fast.)

  • Small leaks not requiring a patch: A urethane-based glue should be used. Some popular brands are SeamGrip® and AquaSeal. Apply a small dab, large enough to completely seal the hole, and allow 24 hours for drying. If your mattress fabric is relatively smooth like the NeoAir or Trail mattresses, peel-and-stick bicycle tube patch kits are an option offering instant repair.
  • Larger holes and tears: All mattresses can be repaired with a self-adhesive fabric patch—like those used to repair jackets and tents. These are commonly found in outdoor gear shops. Cut the patch in a circle to generously cover the hole. Apply a small amount of urethane-based glue to the back of the patch and the area to be covered on the mattress. Apply patch and press firmly. Wipe away excess glue from edges and allow 24 hours to dry.

If you’re not comfortable making the repair yourself and have some time before your next trip, call our service department at 1-800-531-9531 for instructions on sending your mattress back for repair.       


Can I replace the valve on my Therm-a-Rest mattress?

Yes. A Therm-a-Rest Valve Replacement Kit will replace all metal and plastic mattress valves. Instructions for the kit can be found here.

Repair Your Therm-a-Rest Mattress
Repair Your Therm-a-Rest Mattress 



What do I do if water gets inside my mattress?

Roll the mattress up to force the water out of the open valve. If there is a lot of water, you may have to do this several times. Hang the mattress upside down with the valve open in a warm, dry place. It will take about three days for the mattress to dry out. 

Regular cleaning will extend the life of your mattress, especially if you sleep in direct contact with its surface.

Do not put your mattress in the washing machine. Cleaning with a hose or in a bathtub is best. Do not forget to close the valve while washing. For general cleaning, a quick scrubbing with Formula 409®, BioClean All-Purpose Cleaner, or other general household cleaner is best.

Therm-a-Rest mattress care
Therm-a-Rest mattress care 


What’s the best way to remove tree sap/tar?

For tree sap, spot clean with a cotton rag soaked in rubbing alcohol. This will take some work and sap will likely leave a stain. However, a dusting with talc or baby powder when you are done should eliminate any residual stickiness. 


My mattress doesn’t seem to self-inflate. Is it defective?

Likely not. Although all of our foam-core mattresses self-inflate, (the NeoAir mattress does not have a foam core, therefore mouth-inflation is required) the extent to which they do is directly related to the properties of their foam. For example, our Camp & Comfort mattresses inflate incredibly fast because they use a much denser foam with a greater ‘memory’ of its uncompressed state. The ultralight, die-cut foams in our Fast & Light® mattresses on the other hand are chosen for their extremely light weight, trading off some self-inflation efficiency for ultralight performance and may require a few breaths to inflate fully.

If your mattress is new, or has been stored rolled or compressed for a significant amount of time, it could take up to 24 hours for the foam inside your mattress to fully regain its loft and maximum self-inflating efficiency. To help with this, we recommend inflating your mattress fully by mouth to help stretch the foam core back to its original loft. 


What’s the best way to inflate my NeoAir mattress?

Unroll your NeoAir mattress and open the valve. Blow air into the first section of the mattress and close the valve. Push the air from the inflated section into the bottom, non-inflated section of the mattress with the valve still closed. Open the valve and continue inflation. A regular length mattress takes an average of 20 strong breaths to inflate fully. Once inflated, you can personalize firmness by lying on the mattress with the valve near your head. Simply reach up and open the valve slightly to create your ideal level of support.

Using your NeoAir mattress
Using your NeoAir mattress 


Will moisture build-up and ruin my mattress if I blow into it?

No. We have spent decades refining our coatings and fabrics to withstand such things and this assurance of lasting quality separates Therm-a-Rest mattresses from every other competitor. However, minimizing moisture is always a good idea. Always allow self-inflating mattresses to inflate on their own as much as possible, then just top them off with a few breaths at the end for added firmness. We also recommend storing your mattress unrolled and with the valve open. This keeps the foam core at maximum loft and allows any moisture build-up to evaporate slowly. 


Will my breath freeze when blown into my mattress at low temperatures?

As your warm breath condensates in the cold, it is possible in extremely low temperatures to get a small accumulation of ice crystals inside your mattress. However, these pose no puncture hazard to any of our mattresses and the moisture itself is not a problem at all. (See “Will moisture build-up and ruin my mattress if I blow into it? “)


My NeoAir mattress loses air throughout the night. Do I have a leak?

Unless your mattress is going completely flat, it is unlikely that you have a leak. What you are noticing is the natural effect of cooling. The air you are inflating your mattress with is at body-temperature and, like all air, it contracts when cooled. A few more breaths once the mattress has cooled to ambient temperatures should suffice. 


What’s the best way to store my mattress?

NeoAir: Your NeoAir mattress can be deflated and rolled tight for storage. We recommend leaving the valve open and storing your mattress in a stuff sack to protect it from dirt and sharp objects.

All Self-Inflating Mattresses: Store all self-inflating mattresses dry, unrolled and with valves open. Beware of extreme heat in places like attics and parked cars that can damage your mattress permanently. Under a bed or behind a couch that’s against a wall are good, space-saving options.

RidgeRest® or Z Lite Closed Cell Pads: Store your RidgeRest pad flat or loosely rolled. Z Lite pads can simply be stored in their pre-formed accordion folds. Though fine for active use in the field, neither should be stored long-term with straps to hold it rolled or attached to a pack or under heavy objects. This can permanently deform a closed-cell mattress.

Therm-a-Rest mattress care
Therm-a-Rest mattress care 


What side of the mattress do I sleep on?

Sleep on the side with the logo. It is made of our nonslip fabric to ensure that even with a slippery sleeping bag, your mattress stays under you all night long. The bottom is generally a more rugged fabric that adds protection from punctures and abrasion. Some of our mattresses also come with small urethane dots on the bottom to prevent them from sliding around during the night. 


What is R-Value?

R-Value is a measurement of a given material’s resistance to heat flow. The higher the R-Value, the greater the insulation provided. 


How is heat lost while sleeping?

There are four methods heat is lost while sleeping:

  • Conduction — This is heat loss through two adjacent substances due to a temperature gradient such as direct contact of your warm body with the cold ground, and the primary type of heat loss that a mattress reduces. Without a mattress or pad, you will continue to lose heat until the ground beneath you (e.g. the planet) warms—a battle you cannot win. The higher the R-value of your mattress, the slower this process becomes and the warmer you will sleep.

  • Convection — This is active heat loss when warmed molecules move from one place to another and take the heat with them. In a sleep situation, this is generally encountered when a breeze blows across you or into your sleeping bag, moving away the warmed air around you. Your sleeping bag and tent reduce this method of heat loss.

  • Radiation — The transfer of heat energy between two objects via electromagnetic waves. This heat transfer does not require a medium - think about how the sun warms your face from way out in space on a freezing day. Redirecting those waves minimizes this type of heat loss. The reflective barrier in our NeoAir mattress does just this and contributes to its exceptional warmth.

  • Evaporative — Evaporation occurs when a liquid changes to a vapor. This “phase change" requires energy (heat) and your body is the source of it. There are two ways this cooling takes place.

Insensible or active perspiration is the direct loss of vapor through the skin, such as while breathing. This effect is enhanced greatly when in an extremely dry environment due to the driving effect of a humidity gradient. For instance, the extremely dry air of deserts and high altitudes can vaporize sweat before it has a chance to accumulate on your skin. When inhaled, it pulls more moisture from your body as well, raising the need to be hyper-vigilant when it comes to staying hydrated.

Sensible or active perspiration has a powerful and straightforward cooling effect, via the formation of sweat on your skin. On a hot summer day this is great, but sweating profusely because you are overdressed and overheated in winter can wet-out your insulative layers, requiring vast quantities of heat from your body to dry them with disastrous results. 


How does self-inflation work?

In general, a self-inflating mattress is comprised of an open-cell foam core and an airtight fabric shell with valve. When you open the valve on a compressed self-inflating mattress, the open-cell foam core expands, inflating the mattress passively as it pulls air to the inside. Once inflated, you can adjust the firmness with additional breaths, or by letting air out. 


What’s the best way to pack my mattress?

ProLite, ProLite Plus and NeoAir Mattresses: Most of our ProLite and NeoAir mattress are compact enough to fit in even the smallest packs. For those counting every ounce and carrying a frameless pack, your mattress can be partially inflated, folded and used as a comfortable frame sheet along your back. (This might also work with our Z Lite closed-cell pads, depending on your pack size.) Self-inflating Fast & Light® mattresses can also be folded in half and then rolled, allowing them to fit inside a pack. If you have to pack you mattress on the outside, keep it in a stuff sack, and pack it under your pack lid to keep it protected. Though most pack manufacturers put “pad straps" on the outside of their packs, they are usually at the bottom and expose your pad to undue abuse every time you put your pack down.

Closed Cell Pads and Trek & Travel Self-Inflating Mattresses: In all but the biggest packs, size dictates that you carry these on the outside of your pack. How they fit best will depend on how your pack is setup. Keep all self-inflating mattresses in a stuff sack to protect them. You need not worry about puncturing close-cell pads and they can often be handy to roll things in for protection/storage like mountaineering snow pickets, ice axes and tripods. Be mindful that a pad stored vertically on your pack affords you greater clearance in forests, is less likely to get damaged by a passing branch, and is less likely to bump you off-balance while scrambling or traversing talus.

Using your NeoAir mattress
Using your NeoAir mattress 


Winter Sleeping Smarts

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  • The Ultralight Winter Sleep Solution: For the ultimate, ultralight solution to cold weather sleeping, travel with a small ProLite, ProLite Plus, or NeoAir mattress (depending on temperatures), coupled with a full-length RidgeRest® mattress as a bottom layer. In addition to the essential comfort you need in the hips and torso that this top layer provides, you also get the ultra-efficient boost of warmth from closed cell foam, along with the protection you need for open bivies on bare ground or on ledges. You can also cut the RidgeRest mattress to a custom size, further reducing your load. As a bonus, you can use closed cell foam as a splint in emergencies.

    To pack, roll the ProLite mattress inside the RidgeRest mattress for protection when strapped to the outside of your backpack.

  • Stay hydrated and fed: No one likes getting up in a snowstorm to pee but your body needs energy and to stoke its furnace. At high altitudes, proper hydration also helps blood flow, keeping warm, oxygenated blood freely flowing to your extremities.

  • Dress well: Do you know the old adage about sleep naked to sleep warm? Don’t believe it. Sleeping in at least a base layer will help with moisture management, keeping you and your bag drier and, in cold weather; it’s just more comfortable and easier to get out of your bag for that late night bathroom break.

  • Stay Dry: Wet clothes and/or sleeping bags are a recipe for disaster in cold weather. Ventilate your shelter and stay off the tent floor where condensation accumulates. In the morning, hang things out to dry as the bright sun can dry quite well - even in sub-freezing temperatures. If you’ll be out for more than a night, take every opportunity to dry everything - especially your insulation.