What R-value sleeping pad do you need at 40F?
TaskStar 4" Self Inflating Sleeping Pad for Camping with Pillow
$49.99The listing states R 9.5, which covers the R 2.5 a 40F night calls for.
Check price on AmazonSpecsWhat R-value do you need at 40F?
40F is three-season territory. The ground pulls heat out of you much faster than air, and your sleeping bag insulation is crushed flat underneath you, so the pad does nearly all the work below you. On the ASTM F3340 scale most brands now use, an average sleeper on a tent floor wants about R 2.5 at this temperature.
| Sleeping on | Warm sleeper | Average | Cold sleeper |
|---|---|---|---|
| Tent floor | R 2 | R 2.5 | R 3.5 |
| Cot | R 3 | R 3.5 | R 4.5 |
| Car cargo floor | R 2.5 | R 3 | R 4 |
| Air mattress | R 3 | R 3.5 | R 4.5 |
Car camping pads for 40F nights
Where a listing states its R-value we show pads that meet this target; otherwise the thick car camping pads in the catalog, so check each listing's stated figure.
- TaskStar 4" Self Inflating Sleeping Pad for Camping with Pillow$49.99Check priceSpec sheet
LLUAII Self Inflating Sleeping Pad with Electric Pump$70.99Check priceSpec sheet
Hikenture 4" Thick Self Inflating Sleeping Pad$85.49Check priceSpec sheet
Hikenture 4" Thick Self Inflating Sleeping Pad with Electric Pump$109.99Check priceSpec sheet
What else keeps you warm at 40F?
Around 40F, cots and air mattresses start to feel cold from below. Add a foam pad or a wool blanket on top of either, wear a dry base layer and a hat to bed, and eat something before sleeping.
Cots and air mattresses
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Frequently asked questions
Is an air mattress warm enough at 40F?
Not on its own. A standard air mattress insulates at roughly R 1 or less, and at 40F you want about R 3.5 under you. Lay a foam or self-inflating pad on top of the mattress, under your sleeping bag, to close the gap.
What sleeping bag rating do I need for 40F?
Choose a bag whose comfort rating, or lower limit if that is all the maker lists, is about 30F, roughly 10 degrees under the expected low. The pad and the bag work as a system: a warm bag on a thin pad still sleeps cold, because the insulation underneath you is crushed flat.
Can I stack pads to reach R 2.5?
Yes. R-values add, so a closed-cell foam pad around R 2 under a self-inflating pad around R 1 reaches about R 2.5. Put the foam on the bottom to protect the inflatable from punctures.
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Used only to send the list. You can also read every setup free on this site.Researched guidance, not professional advice. Figures are published specifications or clearly labelled conventions; check your own gear's manual and your campground's rules.