Retrofit Wi-Fi is possible only when the indoor model has an official adapter or a port the manufacturer still supports. Many older splits have neither. A plug-in infrared gadget or a smart plug is not the same as integrated control of mode, setpoint and fault codes. Send the model code from the rating plate and ask whether that code has an adapter. Do not buy a dongle on a promise that every old unit can take one. Adding the adapter does not change F-gas rules if the refrigerant circuit is opened, and it does not change Planning Portal duties for the outdoor unit.
The rating plate, not the name on the remote
Manufacturers sell Wi-Fi modules for particular indoor series and production years. The module plugs into a socket on the board or the display. If the series was built without that socket, there is no official retrofit. Read the code on the indoor rating plate, not the name on the remote. The remote often covers a family. The plate is the machine. Age is a clue, not proof.
An official adapter in that brand's app
The installer fits the manufacturer's adapter, connects it to the house Wi-Fi, and shows mode, setpoint and a simple schedule in that brand's app. Ask whose app it is and whether it needs a subscription. Ask what happens to an existing wired controller if you add the module.
Replacement indoors when the plate has no port
If the plate shows no supported adapter, the honest answer is a replacement indoor unit, or living with the remote. Replacement is an F-gas job. A Wi-Fi module on its own should not involve the refrigerant. Outdoor siting rules in England stay on the Planning Portal either way. Do not open the refrigerant circuit for a Wi-Fi job.
Frequently asked questions
Can any old split get Wi-Fi?
No. Only if that model has an official adapter or port. Many older units have neither. The rating-plate code is the check.
Is an infrared smart remote the same thing?
No. An infrared blaster stuck opposite the unit can pretend to be the remote if the line of sight is clear and the codes match. It fails when the sun heats it, when someone puts a book in the way, or when the code set is wrong. It will not read fault codes from the board. It is not integrated control.
Does fitting a dongle require an F-gas engineer?
Opening the refrigerant circuit does. Plugging in a supported adapter usually does not. If the answer is a new indoor unit, that install does.
Can a smart plug be the controller?
No. A smart plug that cuts mains power is a poor controller. Splits are not designed to be power-cycled as their thermostat, and killing the supply can lose settings and interrupt a defrost. Neither an infrared gadget nor a smart plug becomes official because a listing said universal.
Does a newer fascia from the same brand prove the old unit has a port?
No. A newer fascia in the same brand name is not evidence that a ten-year-old unit can take the new dongle. The indoor model code on the rating plate is the check.
Core buying guides
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Related guides
Sources and further reading
How this guide was prepared
This guide was written by the Local AC Installers Editorial Team. We compare official guidance, legislation and established consumer information, separate general information from project-specific advice, and show publication dates and sources. We do not accept installer accreditation claims at face value.