Whole-house auto-control

Modern airtight Japanese homes increasingly run on a single ordinary residential AC unit that serves the whole house through ducted vents (“central HVAC” — Mitsui Home’s Smart Breeze One is a common Japanese example). The trick of the design is that it’s not an oversized industrial unit, just a regular household AC — the high insulation and ducting are what extend its reach. The problem unawair was originally built to solve lives in exactly this setup: the AC’s built-in thermometer reads the air right next to itself (often inside a dedicated HVAC room or the ceiling space), so the rest of the house drifts hot or cold even when the AC thinks it’s done. Distributing several thermometers across the living rooms and averaging them as the “representative house temperature” smooths that bias.

Who it’s for

• Detached homes with Mitsui’s Smart Breeze One or any “single residential AC + ducts to every room” central-air setup
• The AC body lives in a dedicated HVAC room or in the ceiling space — you can’t reach it from the hallway with a remote
• The AC’s own sensor is in the airflow path, so it disagrees with how the house actually feels
• You don’t need fine per-room control — the goal is “the house sits in a comfortable band overall”
• Comfortable running 24/7 without large swings in electricity cost

What you need

	Recommended	Why
IR transmit hub (in the HVAC room)	SwitchBot Hub Mini (or Hub 2 / Hub 3)	Sends IR to the AC + relays the meters’ Bluetooth to the cloud
Thermometers (2–3+, in living spaces)	SwitchBot Meter or Meter Pro	Distributed sensing → averaged “house temperature”
AC	Smart Breeze One or any residential-IR-controllable central unit	The control target
Subscription	Solo plan (¥500/month, 1 automated area)	One area covers it

SwitchBot is the strong recommendation here because you can add cheap standalone thermometers freely. SwitchBot Meters (~¥1,500–3,000 each) sit under any SwitchBot Hub, and unawair averages all of them as the “house temperature.” The scaling-out of distributed thermometers is what makes this use case actually work.

Nature Remo, by contrast, has a built-in thermometer in each unit but no standalone-thermometer SKU — you’d need a second vendor anyway to grow the sensor fleet, so the simpler answer is to start with SwitchBot.

Real-world example (the developer’s own home)

The setup that triggered unawair’s development is Smart Breeze One + a hybrid of Nature Remo and SwitchBot Hub + a small fleet of SwitchBot Meters across the living spaces. The Nature Remo handles IR transmission to the AC in the HVAC room; the SwitchBot Hub acts as the Bluetooth bridge for the SwitchBot Meters (which can’t reach the cloud on their own and need a Hub to relay readings).

Register both vendors with unawair, point one area at all of them, and unawair averages the meters across both vendors for the decision and dispatches the IR command through Nature Remo.

The road to unawair (March 2021)

The idea behind unawair started 5 years ago when the developer first installed a Nature Remo at home and could finally see every room’s temperature on one screen. That personal-use dashboard is essentially what was generalized into the SaaS you see today.

Day the Nature Remo went in at home ↗

The personal home dashboard that became unawair's prototype ↗

Placement tips

The IR transmit hub goes inside the HVAC room — with Smart Breeze One the AC body is in a dedicated utility room separated from the living space, so the hub has to live in there for IR line-of-sight.

• Place the thermometers in the rooms people actually use (living room, bedroom, study, kid’s room). The HVAC room itself usually gets none.
• Average 2–3 thermometers for a stable house-wide reading. A single thermometer is too sensitive to one room’s window being open or sunlight hitting one spot.
• If the hub in the HVAC room has a built-in thermometer (Hub 2 / Hub 3 / Nature Remo mini 2), that reading sits in the airflow path — bind it with the “Near AC” role in unawair so it gets logged but excluded from the control decision.

Setup walkthrough

1. Connect the integrations: if you’re running Nature Remo + SwitchBot, connect both. Register the hub + thermometers + AC in each vendor’s app first → Connect SwitchBot / Connect Nature Remo
2. Create one area: name it “Whole house” or similar, with:
   • Thermometers: the distributed ones as Indoor, the sensor inside the HVAC room as Near AC
   • AC: the Smart Breeze One unit (registered via Nature Remo)
   • → Create an area
3. Comfort range: 22°C – 26°C is a typical starting band. Tighter ranges work fine in well-insulated homes.
4. Manual run once from the dashboard to verify the AC responds.
5. Subscribe to Solo (one area is enough).
6. Switch Auto apply ON.

Why this works

Central HVAC systems like Smart Breeze One put the AC body in a utility room separated from the living spaces. The AC’s own thermometer reads the air around itself, so it shuts off as soon as that spot hits the setpoint — even when the ducts haven’t yet brought the rest of the house up (or down) to comfortable. By the time the rooms catch up, the AC has already overshot in the other direction.

Driving the decision off the average across distributed thermometers stops that. The averaged reading moves more slowly than any single point, so the AC doesn’t whip-react to a window being opened, sunlight hitting one room, or someone walking into a previously empty room — it just lets the whole house settle into the band.

Variant: separate AC in each room

If every room has its own AC and you want them driven independently with per-room comfort ranges, the layout changes (one hub per room, one area per room, Pro plan recommended). See Per-room auto-control for that scenario.

Next steps

• Integration — start by registering the hub and thermometers on the vendor side
• Create an area — multi-thermometer role assignment (Indoor / Near AC)
• Supported hardware — the recommended bundle for the “central HVAC” setup