My girlfriend and I both replaced our mattresses this fall. Because we have different sizes of mattresses and different preferences, and neither of our first picks worked for us, I ended up trying out almost all of the popular online mattresses. I also spent some time learning about mattresses before making my second pick, so this post will be a guide to how to pick a mattress, with some specific advice regarding the mattresses we tried.
Price
We looked at mattresses in the $700 to $1500 range for a queen and $500 to $1200 range for a full. Nothing cheaper than that really interested me, but in my opinion, there's no reason to spend more than about $900 on a mattress (even less if you don't like memory foam).
If these are outside of your price range, you can find cheap barely-used mattresses on Craigslist (just make sure they've been used with a mattress protector and inspect them carefully!). The only reason I didn't buy mine on Craigslist was that I had no idea what I wanted.
Foam vs. springs and temperatures
This post is mostly about foam mattresses because latex or other bouncy foams are more comfortable and more durable than spring mattresses. Springs create pressure points and require overly-complicated construction to counteract that (pillow tops). The only benefit of spring mattresses is that they can retain heat less.
From what I've seen, memory foam retains the most heat, latex less, and springs even less than that. Other things that effect heat are softness (if you sink in more, you'll be insulated more) and channels added for airflow. Some foams are designed with "cooling gel", but I can't tell the difference.
If you get really hot at night and have already done the obvious fixes (use a lighter blanket and use an air conditioner), you might want to consider a spring mattress or a foam/spring hybrid. If you already have heat issues with your bed, you probably don't want a memory foam mattress (but might be fine with latex).
Mattress layers
Foam mattresses are built in layers, with the top layer generally being soft, followed by a slightly more firm layer, followed by a hard support layer (to prevent sagging).
Since the top layers (the "comfort layers") are what you interact with most, you should care the most about that part. You should just ignore the composition of the support layer, since you won't ever feel it in a good mattress. In my experience, a good mattress should have at least 3" of foam in the comfort layers, and depending on the softness, your BMI, and the size of your hips, you might want it to be even thicker to avoid "bottoming out" and feeling the support layer. Most good mattresses have at least 4" of foam in the comfort layers and some companies (like Sleep Science) do 6"+ comfort layers.
For example, the Helix Sleep mattress has 2" of bouncy foam, 2.4" of springs and 6" of support foam. The problem is that the spring layer feels like little metal springs, so you're effectively sleeping on 2" of bouncy foam. This mattress is customizable, so it's possible it would be better in other configurations.
My girlfriend had similar problems with the Leesa, which has 2" of soft bouncy foam and 2" of memory foam. I thought it was comfortable, but it hurt her hips when she slept on her side. The mattress she eventually picked has 4" of latex in the top two layers, and I suspect it works better for her because they are more supportive (although still very soft feeling).
Bouncy / springy
This is the kind of mattress most people are familiar with, and probably what most people will want. If you're familiar with a spring mattress, imagine that but with the ultimate pillow top where you can't feel the springs at all.
If you want this kind of mattress, my favorite is the Leesa, which has 2" of bouncy (non-latex) foam followed by 2" of memory foam (technically a hybrid; see below). My girlfriend prefers the "#BestMattressEver" from Brooklyn Bedding, which has 4" latex in the top two layers. Be warned her "#BestMattressEver" full mattress was slightly smaller than any of the other fulls we tried.
You can also find extremely cheap mattresses on Amazon with 3" of latex in the top layer(s), but I have no experience with them.
High density (Tempur-pedic-style) memory foam
This type of mattress initally feels hard, but quickly conforms to your body as it warms up. Some people describe it as awful quicksand-feeling, and some people think it's the greatest material of all time. Memory foam tends to be hotter than springs or latex, and the "cooling gel" memory foams are a joke. If you don't love the feel of memory foam, you'll probably be happier with a bouncy foam.
Memory foam is measured by density (the weight of one cubic foot of foam), and there's a complicated relationship between foam density and firmness. Higher density memory foams tend to be higher quality and more firm. Because of how memory foam works, "more firm" doesn't necessarily mean "hard" though, since a higher density memory foam will still conform to your body. Tempur-pedic uses 5 lb memory foam, and in my experience, it makes a big difference. 3 lb memory foams tend to be too soft, and don't contour as well.
If you want this kind of mattress, I recommend buying your mattress from Costco. They sometimes sell Tempur-pedics for around $1500, so the $50 membership is nothing compared to the $2000 price difference. They didn't have any Tempur-pedics in stock when I bought my mattress, so I got a Sleep Science Ara (also Costco-only), which was $600 cheaper and has excellent materials (6.6" of 5 lb memory foam in the top two layers).
I haven't slept on it yet, but my parents have the eLuxurySupply mattress in their guest bedroom, and my initial impression was that it's surprisingly-decent for a $450-650 mattress. I'm skeptical because it's only 3" of 3 lb memory foam, but my girlfriend's (one night) experience was that it was surprisingly comfortable for her, although she's not a fan of the memory foam feel.
If this is your first memory foam mattress, you should buy from a company that allows returns, since they're expensive and most people don't like them. Be aware that mattress stores frequently only offer exchanges, and some companies (like Tempur-pedic) won't refund shipping costs.
Hybrids
You can buy a mattress with a combination of memory foam, bouncy foam and/or springs. The top layer is really the only thing you'll feel, but these can significantly effect how hot the mattress feels.
The Helix Sleep mattress is a bouncy foam/spring hybrid. It sleeps cool and the top layer is very nice, but I thought the springs were uncomfortable. It's customizable to a certain extent, so it's hard to say if my experience is common.
The Leesa is an bouncy foam/memory foam hybrid, but I'm not sure what the point of the memory foam is. It feels similar to a pure latex mattress.
Hard low-density foams
If you like the feel of extremely hard mattresses (sleeping-on-the-floor hard), Tuft and Needle has a well-made, very hard foam mattress. This is not memory foam so it won't conform to your body. I used this as my primary mattress for a while, and while it was a huge step up from my ancient spring mattress, it was way too hard for me.
Mattress protectors
Most mattress warranties require that you use a mattress protector, and keeping your mattress in good condition will allow you sell it for more on Craiglist if you decide to get rid of it. One thing that surprised us was that different mattress protectors significantly altered the feel of our mattresses.
Unfortunately, most reviews of mattress protectors are comparing them to either nothing, or a mattress topper. Very few people compare mattress protectors to each other. I've previously used random $30 mattress protectors from Amazon (like Protect-A-Bed) and they all feel the same and made my mattresses feel a lot worse. This time, I took a chance on a Malouf Sleep Tite mattress protector and I can't recommend it enough. It's so thin it's translucent, and it when it's on a mattress, it feels like it's not there at all. Don't buy it directly from Malouf though, since Amazon sells them for a lot cheaper.
Toppers
Toppers are awful and I don't recommend any of them. Buy your bed from a company that allows returns instead. The only time a topper would be good is if you have a well-made non-sinking mattress which is way too hard (like a Tuft and Needle), and you can't return it or buy a new mattress. In that situation, I would buy the Serta 4" 4 lb memory foam topper or a 3" or thicker latex topper. Tempur-pedic also makes a 3" topper which is probably good, but it's $300, I've never tried it, and they don't accept returns.
Summary
Follow this flowchart (edit: made much nicer by Kiley Graim!), and if you run into problems:
- Visit a mattress store to figure out what you like.
- Make sure you buy from a company with a good return policy!