Withings vs Radar: Under-Mattress or Above?

Two Ways to Track Sleep Without Touching You

If you've decided you don't want to wear anything to bed — no ring, no watch, no strap — you're left with two fundamentally different contactless philosophies:

1. Measure through the mattress. A thin sensor pad under the mattress feels the tiny mechanical forces your body produces — heartbeat, breathing motion, position shifts. This is the Withings Sleep Analyzer approach, and it's the mainstream one.
2. Sense through the air. A small radar unit — in Komori's case mounted above the bed — reads position and movement directly, through blankets, without touching you or the bed.

They sound interchangeable. They are not. They measure different physical phenomena, produce different data, and fail in different ways. Disclosure up front: I'm the founder of Komori Care, which is building a radar-based monitor that is not yet shipping — Kickstarter is planned for Q1 2027. The Withings pad is a product you can buy today, and where it's the better answer, I'll say so.

What the Pad Actually Measures

The Sleep Analyzer is a pneumatic sensor: your heartbeat and breathing create pressure changes it reads through the mattress. From that signal, Withings derives heart rate, breathing rate, snoring episodes, and sleep cycles, presented in one of the better consumer health apps. In Europe it carries a CE marking for sleep apnea detection; in the US it's marketed as a wellness device. It costs around $130 and has no subscription.

Its genuine strengths:

• Cardio-respiratory trends today. If nightly heart-rate and breathing-rate trends are the data you want, the pad delivers them now, at consumer accuracy, for very little money.
• Zero habit change. Install once under the mattress and forget it exists.
• A decade of maturity. Proven product, stable app, established brand.

Its structural blind spots — not flaws, physics:

• Position is invisible. A pressure signal through a mattress can't reliably tell your back from your side. If sleep position is what you care about, a pad can't see it.
• The mattress is part of the sensor. Signal quality depends on what's between you and the pad; a thick or heavily damped mattress attenuates what reaches it.
• Two people, one signal. Under-mattress pads struggle to cleanly separate partners sharing a bed — a weakness across the whole category, as we noted in the full contactless comparison.
• The room is invisible. The pad knows nothing about temperature, humidity, CO2, light, or noise — the environment your sleep happens in.

What Radar Actually Sees

A 60 GHz radar sensor emits low-power radio waves and reads the reflections — through blankets, in complete darkness, with no camera and no contact. We've written a plain-English explainer on how radar sleep sensing works, but the short version: radar sees geometry and motion. Where a pad infers your night from pressure, radar observes it — where you are, how you're oriented, when you move, whether the bed is occupied.

Radar-derived heart-rate and breathing-rate systems do exist at clinical accuracy — inside regulated medical channels. They aren't consumer products, and no consumer radar device should claim otherwise.

What radar sensing is genuinely good at, in consumer terms:

• Position. Distinguishing orientation through a blanket is exactly the kind of geometry problem radar is built for.
• Presence and movement. In-bed versus out-of-bed, restless versus still, without mattress dependency.
• Nothing touches anything. No pad to position, no interaction with the mattress, no contact with the sleeper.

And its honest limits: consumer radar doesn't give you the cardio-respiratory trend lines a pad gives you today, and the category is younger — fewer shipping products, less accumulated validation.

Head to Head

That fourth column matters: Komori's capabilities are design intent for a pre-launch product, not verified consumer claims. Komori is a General Wellness device with no FDA clearance. It is not a medical device and is not intended to diagnose, treat, prevent, or cure any condition.

How to Actually Choose

Buy the Withings pad if: you want heart-rate and breathing-rate trends, you want them today, and you want the cheapest competent contactless option from an established brand. For most people asking "should I get a contactless tracker right now," this is the answer, and it would be silly of me to pretend otherwise.

Wait for radar — or join a waitlist — if: the questions you actually have are about position, restlessness, bed exits, and the bedroom environment itself, and staging-and-scores tracking has never told you anything you could act on. That's the gap the radar category exists to fill, and it's the one Komori is being built for.

Both is not a crazy answer. A pad and a radar sensor don't compete for the same physical signal. One reads your cardio-respiratory rhythm; the other reads your night's geometry. Some households will genuinely want both views.

The Honest Bottom Line

The Withings Sleep Analyzer is the best product in its form factor and the safest contactless purchase of 2026. It also cannot see the things the pad physically cannot see: your position, your movements in context, your room. Radar can — and the consumer radar category is only now arriving to prove it.

Buy for the question you're actually asking. If it's "how is my heart doing overnight," the pad answers it today. If it's "what is actually happening in my bed and my bedroom all night," that's the question we started Komori to answer.

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Komori Care is a contactless sleep monitor in development — radar + ambient sensing, no wearable, no camera. Kickstarter launching Q1 2027. Join the waitlist to get notified when we ship.