The eight sleep bed is a popular self-cooling bed. Sleeping on a colder surface not only feels great but often improves sleep as well. This post discusses a cheaper homemade option that I use instead.

Why I didn’t Buy an Eight Sleep

Although many of my friends are happy eight sleep customers, I was put off by the product due to the now-mandatory paired subscription ($200/yr with purchase, annually paired only, can cancel after but lose features), the excessive marketing featuring strange futuristic animations with terms like ‘AI simulations’ and ‘sleep autopilot’, constant paid referral links (similar to products like AG1 which succeed only due to this), and the high price point of $3,000-$4,000+.

As of 2025 Eight Sleep purports to be working on a “personal Sleep Agent, running infinite nightly scenarios before they happen” and “thousands of Longevity Twins simulating potential health outcomes based on your data”. I don’t understand what either of these sentences mean, so I cannot make claims about them, but if these features sound enticing to you then you may not be the intended audience for this post.

I already have a mattress that I like, so I don’t feel the need to replace it. I also inherently dislike the thought of paying a subscription to sleep, and the proprietary nature of the data and cloud app certainly don’t help the case (although I found one user who reversed it).

Popular Alternatives

Here are a few categories of products in the space:

• Eight Sleep: $2400 to $7600 depending on options (full mattress)

• Chilipad: $574 to $1300 depending on options (mattress topper only)

• BedJet 3: $429 to $949 (mattress topper only, pretty loud)

• Random Chinese Amazon items: $140-$300 (topper + evaporative cooler, generally not good products)

• Cooling gel mattress pads: $90 (does not actually cool – just a high-ventilation material)

Current Solution

Here is my current setup, inspired fully by this tweet:

1. Low-quality cooling system with a topper: Adamson B10 Gray Bed Cooling System ($140)
2. Replace the above low-quality evaporative cooler with a Poafamx Fish Tank Cooler ($180)
3. A stronger pump ($15) and small extension tubes ($9)
4. A small cooler which allows me to get the temperature extra low before bed ($18)
5. A Smart plug in order to turn the system on and off from my phone ($20)

The total came out to $382 (without counting 5% off via Amazon) although you could reduce this by at least 15% by purchasing from AliExpress (or much more if you properly source from Alibaba). It’s also possible to save on step one by finding only the mattress topper, but I didn’t want to look through Alibaba for this.

This setup is 1/8th the cost of an eight sleep so I named it the 1/8th sleep.

How It Works

At first glance it may seem complicated to buy six items, but it’s actually a simple setup. The first item comes with a mattress topper which you can run water through (the low-quality cooling unit it came with was not used). It was placed under the first layer of sheets, making it difficult to notice and aesthetically nonmodifying.

Next you need a way to continuously pump water through the mattress topper, which the pump and cooler are used for (you could just have a pump but the cooler gives you a water reservoir which simplifies the process and allows for more control).

Lastly you need to cool the water, which the fish tank cooler is for (water flows into it and comes out cooler).

The extension tubes were purchased so that I could move the setup out of my bedroom entirely both to reduce noise (which was already low – the equivalent of a desktop PC fan) and to ensure any heat output went elsewhere. I placed the tubes near a baseboard and put them under the corner of a door, making it hard to notice I’ve modified my bed at all.

The smart plug allows me to perform a single tap on my phone to turn the system on or off.

As an added bonus you can put ice (or something even colder like dry ice) in the cooler if you’d like to sleep on an extra-cold surface.

The eight sleep bed comes with a sleep tracking app, although I have no reason to believe it is better than a whoop or oura. I use an Oura ring to track my sleep and software which pulls from Oura’s API in order to integrate it with the rest of my personal health data. If you’re interested in sleep tracking you may also like Andrej Karpathy’s post comparing the Oura ring, Whoop, and Apple watch.

Tradeoffs Made

All systems come with trade-offs. Here are some for the 1/8th sleep:

Pros:

• Significantly cheaper
• Ability to excessively lower temperature via ice/dry ice
• Ability to further modify the system, e.g. move the cooler out of the room, upgrade only the cooler, cover an arbitrary part of the bed
• Can be paired with any mattress – users may keep their existing beds
• You don’t have to pay a subscription to sleep

Cons:

• Less aesthetic (This can be improved with a bit of effort – I may 3d-print an optimally-sized encasement)
• No ability to heat the mattress (I live in San Francisco, so don’t want this)
• No fine-grained temperature controls via a phone app (I always set it as low as it will cool regardless)
• No built-in sleep tracking (I use an Oura ring which I find to be much better)
• Easier to incorrectly set up: if you don’t tighten tube connectors you could cause a water leak. If you attempt a setup like this it must be thoroughly tested before applying it to your bed!
• The mattress topper linked for this setup is for a twin bed, although you could purchase two or find a larger one
• Eight sleep loses thousands of dollars in potential revenue (contested – many argue this is a pro)

Conclusion

This was initially an experimental setup but I’ve happily used it on and off for around a year now with no issues (having the pump/cooler outside of my room is particularly nice). I’d still refrain from suggesting it to anyone without an experimental/DIY mindset, but this post was just made out of genuine interest and contains no referral links, so you can decide on your own. Sleep is perhaps the most important thing to optimize in your life, so it’s worth thinking about how you can improve it regardless!

Special thanks to everyone who responded to the initial tweet on the topic, especially this response which inspired this setup.

Read another random post / Back to my homepage