No-Install Smart Control for Rental ACs
Renters photograph a standard AC and its remote to add no-install scheduling and temperature control, with confirmation that each command actually took effect.
After a renter photographs the indoor AC unit and its remote, a small IR-and-temperature sensing sticker identifies the remote’s buttons and commonly used modes. The app first asks the user to test power, cooling, and temperature changes on the original remote. It maps a command only after confirming the unit responds, rather than assuming similar-looking remotes are the same model.
Users can set a bedtime temperature, choose when to switch the AC off after leaving, or start it only when the room exceeds a chosen temperature. When it sends an IR command, the device does not simply report “sent.” It watches the next few minutes of temperature changes and operating sound, then reports that the AC started, may not have received the command, or cannot be confirmed because the environmental change was insufficient.
A simple timeline on the home screen shows plans, completed actions, and unconfirmed states. If the AC does not respond, the app stops retrying, tells the user to use the original remote, and retains the previous settings. The sensing sticker can be removed and taken along when moving, without touching in-wall wiring or the landlord’s account.
The first version supports split AC units with IR remotes and covers only schedules, target temperatures, and execution confirmation. It does not modify the unit, support central air conditioning, or take autonomous control when identification fails.
Why now
On July 30, a rental AC retrofit post ranked 15th on Hacker News, with 98 points and 80 comments. S1 It makes renters more likely to notice that, even without touching in-wall wiring, automated control still needs to confirm whether the AC actually carried out the command.
Target user
The core user is a renter with an IR-controlled split AC in the bedroom. They want to set temperatures before bed, when leaving home, or during an unexpected late workday, but cannot alter wiring or connect to a landlord-managed system. Their biggest fear is a remote command that appears successful, only to find the AC never started when they return. Hardware they can take when moving lowers both installation commitment and deposit concerns.
Minimal entry point
The hardware can use an ESP32 with IR transmit-and-receive capability, a small temperature sensor, and a MEMS microphone. Existing ESP32 libraries can transmit and receive multiple AC IR protocols and store raw pulses. S2 Pairing starts with photos to organize the buttons, then asks users to test each one. The first version learns only power, cooling, and temperature adjustment rather than building a full model database. Confirmation begins with rules that compare pre- and post-command temperature slopes and sound features. If neither signal is sufficient, it returns only “unable to confirm” and does not retry. Audio features are extracted on-device, with no raw recordings uploaded.
Punching above its weight
Reach the first users through rental housing, mini-split AC, and Home Assistant communities. Show a removable installation in use and publish a confirmation timeline from an IR command that was missed. Then offer a compatibility sign-up page where users can submit photos of their AC and remote. Each newly verified remote can become a searchable model page and build organic traffic for the next wave of users.
Competitors & gaps
- SwitchBot Hub 2Google
- SwitchBot Hub 2 already controls IR appliances and uses temperature and humidity, schedules, scenes, and geofencing for automation. S3 Users can also connect other SwitchBot devices, giving it a more complete universal-remote and smart-home ecosystem. Its public page also mentions air-conditioner state sync, so users will naturally expect the basics of control to be mature. S3 The opening is that its page does not say it verifies, after every command, whether the physical AC responded by combining the temperature curve with operating sound. What renters worry about is seeing “on” while away without knowing whether the IR signal was blocked or missed. This product needs to clearly distinguish sent, confirmed, and unconfirmed. When confirmation fails, it should also stop retransmitting so the reported state does not drift further from reality. Its installation should emphasize that it can be removed and taken along, rather than growing into a whole-home hub.
- Sensibo Air ProGoogle
- Sensibo Air Pro is designed for air conditioners and heat pumps with remotes, and already offers IR reception, temperature and humidity sensing, schedules, and a range of smart-home integrations. S4 Its compatibility coverage and maturity are clearly stronger, and users can complete routine control without understanding IR codes. Its official materials also specify a line-of-sight requirement, showing that IR placement remains a practical installation constraint. S4 The gap is that its public materials do not say it verifies each command using operating sound and subsequent temperature changes. It is more like a full smart AC controller, whereas this product can put low-commitment installation for renters first. Pairing retains only commands validated by pressing the original remote, reducing mistaken matches between similar remotes. A failed status should directly tell the user to use the original remote, rather than letting the app’s virtual state continue to pose as the device’s state.
How it makes money
Sell a temperature-sensing sticker and IR controller as a per-room kit. Scheduling, temperature control, and local execution records are unlocked once with the hardware. Optional remote history storage can be offered as a subscription without affecting core control.
The case against
Temperature changes are usually delayed, so it is hard to prove in a short period that the AC has started. Fans, street noise, or other appliances can also be mistaken for a running compressor. A false confirmation could lead users away from home to believe their room is cooling, and that loss of trust would directly hurt retention. The microphone also raises privacy concerns, making local processing essential. Differences in IR protocols and remote state machines across brands will increase compatibility testing and return costs. Even slight errors in sticker placement can affect temperature readings and audio capture. If the product cannot clearly explain an unconfirmed result, its differentiator could instead become a customer-support burden.