Hot Bed

I'm working in Philadelphia this summer and it is starting to get pretty hot out. When I got home from work it was in about 90% out. When I got in the van the first thing I did was open the roof vent and turn on my 12v portable fan to get the hot air moving out of the van. When I'm in town I keep the fan going 24/7. I was out of town last 3 days so van was locked up tight. 

Once the sun started going down the temps start to drop fairly quickly. I was at a Target so I parked in the back and had the back doors and slider open for a while thinking this would help air it out quickly and dissipate  the heat. This seemed to be working ok. After a little while I closed it up and was ready to find my spot for the night. But I also noticed that as soon as I closed the door it felt hotter then I thought it should. All the interior parts felt cool to the touch. Nothing seemed to be holding the heat in... Until I leaned on my bed to reach something. 

Thats when I realized I could feel the heat radiating off of my memory foam mattress. Wow!!! It was holding the heat in. I never really noticed until today. I always thought that some of the interior was holding onto the days heat. But the bed was sucking up the heat like a sponge and holding onto it. Has anyone else noticed this with their setup?

I ended up taking the comforter and blanket off. I usually just sleep on top so my bed is pretty much always made. When I put my hand under the comforter I was shocked at how warm the bed was. Once the covers were off I left the doors open for  a bit to let it air out and it did take some of the heat with it. Just another thing learned during life on the road. Something I never thought about in a regular sticks and bricks place.

That's very interesting. I know some people prefer a warm bed. I prefer a cool bed. In fact, I move around during the night and switch pillows when things get warm. I can't stand the heat. That would really make things difficult for me if I was experiencing what you were.

Good info, I know now to not buy memorie foam.

Memory foam, especially a few years back, was notorious for being hot in the summer. Not just the material, but also the fact that it folds itself around you a little bit as you sink into it, can make for a hot sleep.

These days many companies make all sorts of different layered combinations of different types and densities of foams and gels, many of which advertise how their particular combination helps their mattress keep cooler.

Unfortunately, those mattresses tend to be a bit more expensive than today's decent-quality but inexpensive straight-out foam mattresses. However, prices have plunged so far on foam and gel mattresses that a somewhat pricier gel/foam mix today costs what the cheapest simpler foam mattresses used to cost. And also, there are endless variations of mattress toppers that can help prevent stored heat from reaching your body or, contrarily, your mattress.

I'd like to suggest you get something like a moisture barrier to help, too. I'm thinking of the kind of heavy cloth and plastic-prong material used underneath a mattress to help circulate air below it so as to prevent mold and fungal growth there. Foam mattresses get that VERY easily as the temperature varies and creates condensation down below. It might also help dissipate some heat. I got the Aire-Flow material from Mattress Insider. Several companies sell what looks like the same or extremely similar item under different names. At ten bucks a foot, it cost me a hundred bucks for enough to go under a queen size bed. Gotta cut it to size, unfortunately.

I have both (good Lord you should have seen the fungus/mold under my first foam mattress!!!) a moisture barrier underneath and a dual-layer mattress topper on the top. The latter is also extremely helpful in preventing an accidental spill from getting down into your foam mattress, where you damn sure don't want it to live forever.

I know those two suggestions won't change the thermal mass that a big foam mattress has, unfortunately. But they may help your perceived level of comfort when lying on top of it, and do other things for you as well.

Heat capacity is related to mass, the heavier something is the more heat it will hold. Perhaps you are getting radiated heat coming up from the pavement?

I like the purple mattress but they are way too expensive https://purple.com/mattresses?devic...Gnvi8B3yRQ8tHdd0ImrLcVdummxeQkWRoCWCwQAvD_BwE

I tried a memory foam mattress and I only lasted 2 nights.  I sunk in and it was very difficult to turn over and it was hot even thought it was winter.  I put my inner spring mattress back and will not use memory foam again.  I took the memory foam mattress to out local homeless community and they were very happy and it made me happy to give it to someone who would enjoy it.

I bought a memory foam mattress and have experienced feeling very hot at night, even on cool nights with the windows wide open - using the same bedding and blankets i did with older style innerspring mattresses. Until i read this thread i thought it was me. I’m glad this came up now because i am looking for a narrow twin mattress to outfit a van i am looking at purchasing.

I saw this on Amazon that looks like it may serve my needs but i thought i would get some input on this or any other mattress that the folks here could recommend.

https://www.amazon.com/Zinus-Spring-Mattress-Narrow-Replacement/dp/B074Q6T8NS

closeanuf and Matlida's mate, what you describe does NOT pertain to all foam mattresses, at least not anymore.

If you sink in, you got one that was not firm enough. This is no different from being careful to get one that's firm enough when you're buying an innerspring mattress. Unfortunately, you can usually go to a store and lie down on an innerspring mattress to test it out in person, but can rarely do that for foam beds as most are sold through the mail or rolled up in a box that they can't be stuffed back into. So it usually is a lot more of a gamble when buying a foam or foam/gel mattress. That's why it's very important to read reviews before buying, the more the better.

I had the same experience on foam beds before, the sinking in stuff and the feeling super hot stuff (I am very heat-sensitive indeed), so I feel your pain!

For the latest one I got, I read a lot of reviews. Here it is:

https://www.amazon.com/gp/product/B005A4OO80/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

As one reviewer said, "The mattress is just a touch softer than I would like - I have slept on a firmer Ikea memory foam mattress for many years. But it does not feel like it's trying to swallow you whole, like the memory foam mattresses of yore." He describes it overall as medium-firm, and some describe it as firm. At any rate, I don't sink in even though I put a 3-inch mattress topper on it.

And it's been in the 90's lately, and my top blanket has remained cool to the touch even though the head of my bed is smack up against the front wall of my trailer, which takes the sun all afternoon.

The real test will be longevity, as foam doesn't always stay firm.

I took one of the cheap nylon summer sleeping bags from Walmart and stuffed the memory foam matress inside it and sewed the zipper areas tighter to make the matress compress a little firmer and sleep on the silky outside of the sleeping bag. You could probably use something like thin cardboard or reflex to make it even firmer. Just the silky nylon and alittle firmer matress worked for me. I like it better than my thermorest!