Give me a step by step guide to replicate: The 1/8th Sleep
Posted on October 12, 2024
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.


A 12℉ difference between the bed surface and the surrounding air. Some ice was used in the cooler prior to the image as measuring surface temperature is challenging with the pictured thermometer.
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), the excessive marketing featuring futuristic animations with terms like ‘intelligence’ and ‘autopilot’, constant paid referral links and name dropping of Huberman et al, and the high price points of $3,000 total and $366 for the addition of two pillows and a bed sheet.

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:

Low-quality cooling system with a topper: Adamson B10 Gray Bed Cooling System ($140)
Replace the above low-quality evaporative cooler with a Poafamx Fish Tank Cooler ($180)
A stronger pump ($15) and small extension tubes ($9)
A small cooler which allows me to get the temperature extra low before bed ($18)
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).


An image of the cooler used – I keep it set to as low as it will go which will usually be around 12℉ lower than the air temperature.
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, oura, or apple watch. I use an apple watch to track my sleep which has the benefits of requiring no subscription and of allowing me to export and control my data (Claude wrote me a full script to parse my apple health data with just minutes of work

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
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 Apple watch)
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 setup is experimental and has only been used for one week. While I’m happy with the results thus far, I wouldn’t suggest it to anyone without an experimental/DIY mindset. This post was made not because the setup is optimal but simply because it seems better to post this than to post nothing at all. This post contains zero referral links.