Kelvin OnePreorders open. Ships March 2027.
Warmth, by the degree.
A thermostat that learns when you wake, leave and come home, then heats the house for exactly that. One ring, one glass face, nothing to program.
01The object
Turn the ring. That's the manual.
- 01 / 04
A ring you can feel click.
Machined from one billet of recycled aluminum, then spun-brushed in a circle so light runs around it. It turns with soft detents, half a degree each.
120detents, ½° per click
- 02 / 04
Glass, curved like a lens.
A domed cover glass over a round display that is bright enough for a sunny hallway and dims to almost nothing at night.
2.7 inround, 480 × 480 pixels
- 03 / 04
Barely off the wall.
Shallow enough to sit beside a light switch without looking like a gadget. The trim plate covers the paint scars your old thermostat left behind.
26 mmdeep, 84 mm across, 182 g
- 04 / 04
It glows the way it feels.
Walk up and the face wakes: ice blue while it cools or saves, ember while it warms the house. Walk away and it goes dark in eight seconds.
3 mpresence range, no camera, no mic
02Learns your rhythm
A week of you. Then it just knows.
For the first seven days, turn it whenever you feel like it. Kelvin notes when you wake, when the last phone leaves and when someone turns for home, then writes the schedule you'd never get around to writing.
6:10am
WakeWarming to 69° so the kitchen is warm by 6:10.
- 6:10 amWakeWarm by 69°
- 8:45 amLast phone leavesEases to 61°
- 4:50 pmTurning for homeBack to 70°
- 10:15 pmLights outSleeps at 65°
Week 1
9times you reached for the ring.
Week 2
2once for a cold snap, once for guests.
Week 3
0You forgot it was there. That's the idea.
03The app
Every room, under one thumb.
The app opens on the only two things that matter: how warm it is, and how warm it's going. Everything else is one swipe away.
- 01
Away, without asking
When the last phone leaves, Kelvin eases to 61°. When the first one turns for home, it starts warming, timed to the commute.
- 02
Rooms that report in
Add Room Sensors and Kelvin heats the room you're in, not the hallway it hangs in. Bedrooms at night, the office by day.
- 03
Peak hours, handled
When time-of-use rates peak from 4 to 9 pm, Kelvin pre-warms at 3 and coasts through. Approve it once, save all winter.
04Energy
It pays for itself by the second winter.
Heating is about half of a California home's energy bill. Kelvin spends less of it on empty rooms, sleeping houses and the hour before you actually get home.
23%
less energy spent on heating, measured across 412 homes in Alameda County from November to March.
- $184
saved in a year by the average home on a gas furnace
- 16months
to earn back the $249, sooner with a utility rebate
- 0.8t CO₂
kept out of the air by each home, each year
Kelvin pilot, 412 homes in Alameda County, November 2025 to March 2026, compared with each home's previous winter and adjusted for weather. Your savings depend on your home, your system and your winters.
05Materials
Made like a watch, not a gadget.
No gloss, no blinking lights, no logo on the front. Four materials, each chosen to look better in year ten than in week one.
- Ring
- Recycled 6061 aluminum, machined from solid and spun-brushed in 1,200 passes.
- 41 g
- Face
- Domed cover glass with an anti-glare coat, so you read 68°, not your hallway light.
- 0.7 mm
- Base
- Mineral-filled polymer in warm white. It unclips, so a repair is a screwdriver, not a landfill.
- No glue
- Mount
- One screw, a magnetic plate and a spirit level built into the trim.
- 1 screw
Choose a finish
Shown at about three times life size, in Aluminum.
06Tech specs
Every number, in one place.
| Size and weight | 84 mm across, 26 mm deep, 182 g21 mm off the wall with the optional slim plate |
|---|---|
| Display | 2.7 in round, 480 × 480 pixels, 178 ppiWakes at 3 m, dims to 2 nits in a dark hallway |
| Ring | Recycled 6061 aluminum, 120 detents, half a degree per click |
| Sensors | Temperature (±0.2 °F), humidity (±2%), 60 GHz presence radar, ambient light |
| Connectivity | Wi-Fi 6 (2.4 and 5 GHz), Thread border router, Matter 1.3, Bluetooth LE 5.3 for setup |
| Works with | Gas, oil and electric furnaces, heat pumps with aux heat, boilers and radiant floors, central air. Up to two stages of heat and cooling.About 95% of 24 V systems. Not for 120 or 240 V baseboard heaters. |
| Power | 24 V C-wire, or the Power Bridge in the box for homes without one |
| Privacy | Learning runs on the thermostat, not in the cloud. No camera, no microphone. Clear your history from the ring itself. |
| In the box | Kelvin One, base, trim plate, Power Bridge, four screws, wire labels and a 20-minute install card |
| Warranty | Three years. Repairs and parts offered for ten. |
Kelvin One in AluminumDrag to turn
08Questions
Answered by the people who wired it.
Will it work with my system?
If your thermostat runs on 24 volts, almost certainly: furnaces, heat pumps, boilers and most central air. Send a photo of your current wiring when you reserve and an engineer in Oakland will confirm within a day.
I don't have a C-wire.
Every Kelvin ships with a Power Bridge. It clips in at your furnace and powers the thermostat over the wires you already have. No new wire through the wall.
Does it need the cloud?
No. Schedules, learning and Away all run on the thermostat. The app talks to it over your home network; the cloud only relays commands when you're out.
Who installs it?
Most people do it in about 20 minutes with the card in the box. In the Bay Area our own crew installs it free through March 2027.
What if I don't love it?
Live with it for 100 nights. If it isn't for you, send it back in the same box for a full refund, and we'll leave your old thermostat working.