Most mattress companies offer cooling mattresses as it's clear that heating up while you sleep hurts sleep quality. Mattresses offer lots of options to help prevent the buildup of body heat. But the reality of foam mattresses is that when foam is compressed, it reflects body heat back to your body. So some common options are to use cooling fabrics, gel in the foam, and a hybrid design. A hybrid mattress has foam on top of an innerspring core. Innerspring mattresses don't heat up because body heat releases into the air inside the mattress. But the issue with innerspring mattresses is that they tend to be less soft. So if you add a foam top to an innerspring mattress, you can achieve some balance between softness for comfort and firmness for support.

One of the few innovative mattresses is Purple mattress, as they use an elastic polymer grid that creates spaces for the heat to escape into. Many people love their Purple mattresses, which are medium to firm.

What's great about Eight Sleep and Sleepme (formerly Chilisleep, makers of the ChiliPad) is that they have cooled water running through tubes in a pad that sits on top of a mattress. So if you like your extra-firm or plush mattress, just put the pad on top to control the temperature, regardless of your mattress.

This is the system's best feature and is way better than anything available on the market for cool sleep. The temperature has a range of 55° to 110°.

First, you answer questions about your sleep in the app, and then the system tracks your sleep for seven days to fine-tune your temperature. When you go into deep sleep, it drops the temperature slightly. When you go into REM, it raises slightly. In the latter part of the night, the temperature gradually rises. And it allows you to wake up to a warmer temperature (or vibration, both, or none).

The Autopilot also takes into consideration the weather and room temperature. If it's warmer than normal outside and in your bedroom, the Autopilot will drop the temperature of the cover.

You can have two separate temperatures for you and your partner via the app.

I was disappointed that it took almost a month for my mattress and Pod 3 cover to arrive. They did communicate with me well via email regarding the delay.

The delivery came in 2 boxes, and everything was packed very well. I was out of the country when everything was delivered, and I messaged my neighbor to pick up one of the boxes. When the second box arrived I didn't message him and the cardboard box sat outside for a few days, and it rained a lot. The box had partly disintegrated but the mattress inside was untouched.

The instruction book tells you on the first page to download the app. The app walks you through how to connect the hub to wifi then to the cover, zipping the cover, setting up the hub, etc.

The app does a great job of walking you through every step. The directions are clear and there are gifs that show you exactly how to do what the text says.

The manual directs you to install the app and the app directs you through the installation process. The app did an amazing job up to the point that you need to add water and hydrogen peroxide, then it become unclear.

I was unaware that I had to go back to the paper manual to know the ratio of water to hydrogen peroxide. I was also unaware that a King mattress needs to be primed three times. Priming is the process where you add water and let the hub circulate it through the tubes. The app told me to prime and didn't tell me to do it again. The first night on my mattress was a dud-there was no temperature change. The next day I called support and they told me that the app said that I needed to prime it three times. I paid a lot of attention to the app, and I didn't see it. If it does say it, it needs to be more prominent. The Eight Sleep customer service agent was a little blamey and critical.

This is the view of the back of the hub where you attach the connectors. You can see the fan which is really quiet.

I used the Chilipad Cube for 5 years and the noise was too loud. I kept the Cube under my bed to help reduce the sound, but it was still a lot louder than white noise. At around 15" tall the hub is too tall to put under the bed, but you don't need to as it's quiet.

This white light at the bottom is a status indicator. 9 different colors let you know what is happening, such as cooling, warming, disconnected from wifi, tube unplugged, etc.

The first night of sleep, the light was bright. I'm pretty sensitive to light, and I know that light exposure signals the brain that it's daytime, so I just threw a shirt in front of it. The next day I was playing with the app and discovered that you could change the brightness of this light.

I think this is a good feature, but it would be good to include in the instructions how to dim this light. Some people buying this mattress are dealing with sleep issues; it's reasonable that the setup gives the user the best chance of good sleep.

I used the Cube from Sleepme for years, the Dock Pro from Sleepme for three weeks, and Eight Sleep for two months. Here are my conclusions:

• The Cube is WAY better than nothing, it was a lifesaver for me as I sleep hot, but I can't use innerspring mattresses because of my back issues (innerspring mattresses sleep cooler but aren't super soft. However...
• The Cube is too loud, and it's annoying that you have to refill the water every 5 or 6 days. Many times I woke up really hot because the unit had shut off due to having no water.
• It's also annoying and another cost to add the Chilisleep system cleaner to the water every so often.
• The Dock Pro from Sleepme is more expensive but much quieter and a superior product to the Sleepme Cube, but it still needs to be filled up every six days.
• I couldn't get the sleep tracker from Sleepme to connect to wifi. I read a lot of reviews, and it gets poorly reviewed. Being unable to connect to wifi was one of many common problems.
• The cube didn't have an app; the app with the Dock Pro is ok; it has a lot of limitations.
• The Eight Sleep system is quieter than even the Dock Pro (and the Dock Pro is quiet and an excellent white noise).
• Eight Sleep adjusts the temperature throughout the night and was designed by a sleep scientist.
• I haven't had to fill up my Eight Sleep yet, and it's been eight weeks, and I've read of people having to fill it after 18 months!
• The Eight Sleep app is pretty good, though far from perfect.
• Eight Sleep gives you the option to wake up to the bed vibrating, heating up, both, or none.
• The installation of the Eight Sleep mattress was a dream up to the point that I had to add water; then, it completely fell apart.
• I had some terrible experiences with Sleepme, to the point that I won't be surprised if I hear that they're going out of business. Eight Sleep has been pretty good for customer service.

Eight Sleep gives you the option of buying the mattress with the cover or buying a cover that you attach to your current mattress. Though prices change all the time, to give a comparison, a Queen Pod 3 cover only right now is $2,245, and the mattress with the cover is $3,295. If you buy the Pod 2, which fits 10"-11" mattresses, it's $1,845.

If you buy the cover only (which they call the Pod 3 grid), you have a 30-day trial. If you buy the Pod 3 mattress with the cover, you have a 100-day trial.

Through the app you can have different temperatures for you and your partner, as well as "away mode" for when one of you is absent.

I tested this once by turning one side to 55° and the other to 110°. It works very well.

The Pod Mattress is a 4/10 for firmness, which made it a medium-firm. Medium-firm mattresses are generally good for all types of sleepers: side, back, and stomach. Even if they use the softest foam available, because there's a cover that's zipped around (or over) the mattress, this will create a bit of a firmer mattress, because the cover will prevent you from sinking in as it's attached on all sides. The tubes in the cover also add a little bit to the firmness.

Because of my back issues, I need a really soft mattress, and this isn't a plush mattress. I told customer service that I needed something softer, and they told me to unzip 2 or 3 sides of the mattress on the very bottom (not the zipper that attaches to the pod cover). It helped a little. I added a foam pad under the cover, and I've decided that I will return the Pod 3 mattress and order a plush mattress, then order the Eight Sleep cover. But I think the firmness of the mattress will appeal to a large percentage of people.

Every morning the app will generate a sleep report with some useful information. I like that you don't have to wear a smartwatch to get the info, but the app doesn't always give accurate information. For example, one night, I got up early and worked for a couple of hours, and then went back to bed for three hours. The app was giving me a "Pay Attention" warning in red letters, telling me that I had only slept for 4.5 hours. I think the app sensed that I got out of bed, and it automatically generated a sleep report.

One time I got in bed and could not fall asleep for 45 minutes, but it told me I was asleep. To be fair, apps can only read some basic biometrics if you're moving. If you want to see brain activity, which is how you can see how much you sleep, you need to connect electrodes to your head. Being a sleep nerd, I have looked into this; it's expensive and inconvenient.

So the app is far better than nothing and above average compared to the other sleep apps I've used.

There are two options for the monthly membership: Pro ($15) and Plus ($24). Each membership gives you two accounts per mattress with automatic temperature adjustments, vibration, and thermal alarms, automatic software updates, and health and sleep reports. The only benefit of the Plus over the Pro is the extended warranty.

If you cancel the membership, you won't have the autopilot that changes the temperature as you go through different phases of sleep, nor the vibration and thermal alarm, sleep reports, or software updates. If you're already sleeping well, you may not need all these extras, but if you're trying to improve your sleep, it could be helpful.

The membership is required for the first 12 months and then can be canceled. I'm not a fan of this monthly fee. I don't see other apps, such as an Apple watch, that require a monthly fee. It feels like a money grab.

I was happy that it didn't take too long to talk to a live person about my problems with the installation. She fixed the issue, but she did mention that the temperature in my bedroom the previous night was 71° as one of the reasons why I felt it was hot. That had nothing to do with the mattress not cooling down.

When I told her that I didn't see a message in the app that told me I needed to prime the unit 3 times, she told me the message was there. I was paying attention, and I didn't see it. It could have been my fault, but the way she told me was a little arrogant.

She solved my problem but I think Eight Sleep could be a little more selective with the customer service agents.

Reviews for Eight Sleep are often glowing. You have to consider that they're good marketers, and they have a lot of influencers doing reviews, but there's no denying that their tech is on another level.

Their closest competitor is Chilisleep/Sleepme, and here's how I would rate them based on budget. If you're limited on budget and you need to sleep cooler, the Dock Pro from Sleepme is a good product that will get you to the sleep temperature you need. But if Eight Sleep fits in your budget, it's a far better product.

I'm a sleep coach who is very sensitive to temperature; this is the best product by far. I've tested a lot of mattresses, and for the foreseeable future, this is the setup I will be using. As I mentioned before, I need a softer mattress, so I'll use a plush mattress with the Eight Sleep cover, and I look forward to improvements in the product and the app.

Here are the answers to our most frequently asked questions about the Eight Sleep system.