Bed Cooling Systems: Eight Sleep, Chilipad and More

Home » Bed Cooling Systems: Eight Sleep, Chilipad and Smart Sleep

A bed that cools or heats itself changes how you sleep rather than only measuring it. This hub gathers everything on the5krunner about water-cooled bed systems: Eight Sleep, which I have slept on for more than three years, Chilipad, Somnus Lab, Orion and Qimora, plus the under-mattress sleep trackers that came before them.

Which system to buy

Start with Eight Sleep alternatives: bed cooling systems compared. Where you live decides most of the choice. Chilipad 2.0 and Orion are sold only in the US, and Qimora only in the UK and Europe. Somnus Lab sells in the UK and Europe and takes US pre-orders, and Eight Sleep sells everywhere.

How the systems differ

All five work the same way. A bedside unit cools or heats water and pumps it through a thin layer on top of your mattress, and each side of the bed can be set separately. The differences that matter are tracking, subscription and range.

Tracking. Eight Sleep and Somnus Lab measure heart rate, HRV, breathing and sleep stages from the bed, so there is nothing to wear. Orion sells tracking as a paid extra. Chilipad and Qimora do not track sleep, so pair them with a watch or ring if you want the data.
Subscription. Only Eight Sleep needs one. Its Autopilot membership adds about $1,000 or £1,000 over five years, and it is also what changes the temperature automatically through the night.
Range. Chilipad 2.0 runs hottest, up to 46°C, and Orion coldest, down to 10°C. Qimora cools relative to the room, up to 8°C below it, so it struggles more in a hot bedroom.
Living with it. Every system has a bedside unit that hums a little and a water tank that needs topping up every few months.

Why temperature matters for recovery

Your core temperature has to fall for deep sleep to start, and hard training, a warm room or menopause can all get in the way. In a study of 54 people, Eight Sleep found sleeping heart rate fell and HRV rose by 7% with the Pod switched on, and a menopause study found more deep sleep in women over 45. Both were funded by the company, so treat them as a promising start rather than proof. My own experience is in Athlete’s sweaty sleep: cured.

Reviews and buying guides

Eight Sleep alternatives: bed cooling systems compared
Eight Sleep Pod 6: all you need to know
Eight Sleep Pod 5 review
ChiliPad 2.0 review
ChiliPad 2.0 vs ChiliPad 1.0

Current discounts

Specifications

Chilipad specifications: Chilipad 2.0 and Chilipad 1.0
Eight Sleep specifications: Pod 6, Pod 5, Pod 4 and Pod 3

Features and research

Sleep trackers without cooling

If you only want the data, an under-mattress sensor or a wearable is far cheaper than a cooling system.

Quick answers

Which bed cooling system needs no subscription?
Chilipad 2.0, Somnus Lab, Orion and Qimora all work fully without one. Eight Sleep needs an Autopilot membership.

Which bed cooling systems track sleep?
Eight Sleep and Somnus Lab track heart rate, HRV, breathing and sleep stages from the bed. Orion offers tracking as a paid extra, and Chilipad and Qimora do not track sleep.

Which bed cooling systems are sold in the UK?
Eight Sleep, Somnus Lab and Qimora sell in the UK. Chilipad and Orion are sold only in the US.

Does a cooler bed help athletes recover?
A falling core temperature helps deep sleep start, and Eight Sleep’s own studies found higher HRV and more deep sleep with cooling on. The studies were company-funded, so the evidence is promising rather than settled.

Explore the full resource library

This site covers endurance sport technology across a range of dedicated reference sections. Each one collects the most relevant articles, tests, and analysis on its topic in one place.

Buyer guides

Best sports watch: tested recommendations by sport and athlete type (triathlon, running, marathon, cycling, hiking, and women)
Best Garmin watch: Forerunner versus Fenix by series, sport, and budget
Best wearables: fitness trackers, recovery trackers, heart rate monitors, running power meters, and female athlete tech
Best cycling products: computers, smart trainers, indoor cycling apps, power meters, and cycling heart rate monitors
Buying guides: every upgrade guide and product comparison in one place, by brand, for owners deciding whether to move to the newest model
Gear I use: the watches, bikes, sensors, fuel and sleep kit tfk actually trains and races with, and what his partner uses

Brand and product guides

Amazfit: the full Amazfit range from Balance to Cheetah to T-Rex, accuracy tests, HYROX partnership, and Zepp Health analysis
Apple Watch: athlete-first coverage of Apple Watch across running, cycling, and triathlon
COROS: watches, features, and firmware across the full COROS range
Garmin: the company, the platform and the full range, and the starting point for choosing across every Garmin product line
Garmin Edge: bike computers from entry-level navigation to flagship endurance and mountain biking
Bike computers: Garmin, Wahoo, Hammerhead, COROS and the value brands compared
Bryton: the Rider range compared, from basic GPS units to the S810 with maps
Garmin Fenix: every model, feature, and firmware development for Garmin's flagship outdoor watch
Garmin Fenix 8 Series: which variant to buy, upgrade advice, accuracy data, and the full Fenix 8 review and firmware coverage
Garmin Forerunner: the full Forerunner line covered from entry level to triathlon flagship
Garmin Instinct: rugged GPS watches for endurance and adventure athletes
Garmin Features Explained: how Garmin's metrics work, from Training Load and Body Battery to Race Predictor and HRV Status
Garmin Connect IQ charts: the most popular watch faces, apps, data fields and music services on the Connect IQ Store, updated monthly
Google Fitbit: Fitbit Edge, Fitbit Air, Google Health, Pixel Watch and the Wear OS platform
Magene: which Magene bike computer to buy, from the C506 to the C706, with tested verdicts
Polar: watches, sensors, Polar Flow and training science across the full Polar range
Runna: coach-written running plans that adapt as you train
Suunto: Race, Vertical, Run and the SuuntoPlus ecosystem
Strava: features, privacy, segments, and how Strava fits into a serious training setup
Ride with GPS: route planning, navigation and how it works alongside Strava
Wahoo: KICKR trainers, ELEMNT bike computers, and the Wahoo ecosystem
WHOOP: strain, recovery, sleep and the full WHOOP ecosystem

Specifications database

Full Specifications Database: detailed spec sheets, battery life, sensor lists and generation-on-generation comparisons for current Garmin, COROS, Amazfit, Samsung, Google Fitbit, Huawei, Polar, Suunto, Wahoo and Apple Watch models

Glossary

Sports Technology Glossary: non-branded terminology across running, cycling, swimming, triathlon, hiking, strength training, HYROX, sensors, ecosystems, and brands

Sport and topic guides

Running Watches: how to choose by discipline (road racing, trail, track, beginner, and multisport)
Triathlon and Multisport Technology: watches, sensors, and race-day tools for swimmers, cyclists, and runners
HYROX: training science, race analysis, and technology for the functional fitness race format
parkrun: technology, training, and performance for the weekly 5K
Hiking Technology: navigation, safety, and trail tech for walkers and hikers
Heart Rate Monitoring: optical sensors, chest straps, accuracy comparisons, and how to set training zones
Optical Sensors (PPG): the 40 things a wrist optical sensor could measure, from heart rate to glucose, ranked by evidence
GPS Accuracy: how satellite systems perform across brands, terrains, and conditions
Sports Watch Battery Life: battery claims, real-world tests, and how to manage battery life across Garmin, Apple, Amazfit and COROS
Recovery Trackers: WHOOP, Oura, and the science of readiness scoring
Bed Cooling Systems: Eight Sleep, Chilipad, Somnus Lab, Orion and Qimora compared, with reviews, specs and current discounts
Muscle Oxygen Sensors: SmO2 and NIRS explained, Train Red and Moxy compared, and the category from BSX and Humon to Garmin and WHOOP
Female Athlete Tech: wearables, physiology, and performance for female endurance athletes, covering cycle-synced training, RED-S, HR accuracy, and VO2max
Sports Science: peer-reviewed research on HRV, VO2max, lactate threshold, running power, wearable accuracy, and supplementation
Testing Methodology: how this site tests GPS accuracy, heart rate, battery life, and other performance claims

Content series

Release Radar: confirmed launches, leaks, and rumours across Garmin, Apple, COROS, Polar, Suunto, and Wahoo
Deep Dive Feature Files: weekly firmware feature updates across all brands (bug fixes excluded)
Fix Files: weekly firmware bug fix tracking across all brands

Small things I always use

Garmin 90-degree charging adapter: Charges your Garmin with any USB-C cable. Essential when travelling. I use one.
Body Glide: The blue anti-chafing stick swimmers and runners carry. I use it.
Speedo earplugs: Fewer ear infections and no cold-water dizziness. I use them.
Dryrobe Advance: My winter changing robe for open-water swims. I use one. A cheaper option is the AONYIYI changing robe.
Maurten: Race fuel that stays easy on the stomach. I use them.
Beet It Sport nitrate shots: Beetroot shots I take in the days before a race. I use them.
Garmin charging puck: The quickest way to top up before a session. I use one.
Injinji: Toe socks that stop rubbing, so you run more. I use them.
Ultimate toe protectors: Stop black toenails on long runs. They work. I use them.
Compressport R2 v2 calf sleeves: My calf sleeves of choice. I use them.
Cellucor C4: My pre-workout before hard sessions.
TPU tubes: Schwalbe Aerothan, Tubolito and Pirelli SmarTube. Light, tiny spares. I use all three.
G8 insoles: Adjustable arches, perfect position. I use them.
Cycplus Cube: A 97g electric pump that gets a road tyre rideable in two minutes. I carry one. 5% off with code THE5KRUNNER.

Health, recovery and sleep

Kineon MOVE+: Red and infrared light for sore knees, Achilles and other joints after hard training. I use it.
FreeStyle Libre 3 Plus: Shows how my blood sugar responds to diet. Occasional use.
hDrop: Measures my sweat loss in summer and indoors. I use it.
Fourth Frontier Zone: Checks my heart under load in hard sessions.
Oura Ring 5: My partner’s recovery tracker of choice.
Eight Sleep: A cooling mattress cover my partner and I use nightly.

Watches and sensors

Polar H10: My daily driver for waking HRV.
Polar Verity Sense: My backup arm-worn HR sensor.
Nomad bedside charger: Charges my iPhone and Apple Watch overnight. I use it, and many of their bands.
Train.Red: The best muscle oxygen sensor I’ve used. Occasional use.
Tymewear: Accurate heart rate and reliable ventilatory zones. I use it to pace endurance rides over an hour.
Garmin Forerunner 970: A pro-grade triathlon watch. I use this.
Apple Watch Ultra 4: My daily smartwatch. No phone needed on rides.

On the bike

Continental GP5000 for everyday riding, and Aero 111 on the front for special occasions. I use both.
Helmets: Specialized S-Works Evade 3 for road riding, and Rudy Project Wing for TT-style races. I use both.
Ravemen FR300: A front light that mounts under your Garmin or Wahoo. I use one.
Ravemen FR1000: The light and the computer mount in one unit, so nothing else goes on the bars. Better than mine.
Ravemen FR1500SE: 1,500 lumens hanging under your Garmin, for proper night rides.
Ravemen FR1100SE: 1,100 lumens under your Garmin, and up to 46 hours on slow flash.
Ravemen FR500: A brighter FR300 with the same mount.
Wahoo TRACKR Radar: I use it on one bike and Varia on the other. They perform the same.
Garmin Varia RTL515: Radar that warns you of cars from behind. I use this model.
Wahoo ELEMNT Roam 3: The bike computer that’s easy to use. I use mine on most rides.
Favero Assioma Pro RS2: Accurate power pedals that swap easily between bikes. I use this model.

Home and indoor training

NPE Runn: Makes my basic treadmill smart, sending more accurate speed and distance to my watch and Zwift. I use it.
Google Wifi: Keeps Zwift connected in my pain cave. I use it.
Apple TV 4K: Zwift on the big screen. I use two.
Google Nest Doorbell (wired, 2nd gen): My video doorbell, running in both Google Home and Apple Home via Starling. I use it.

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