I guess so, either SPIFFS or the new FS.
What type of aircon system is it?
I’ve done quite a bit of research into IR, Aircon protocols ad 433MHz protocols and you’ll quickly discover that 90% of the raw data for most aircon systems is padding, repetition or static data. Once you understand the protocol then it’s usually 3 or 4 bytes of data that change per function. After that it’s easy to assemble your data string from these components and send them, with preamble and repetition as necessary,to activate the functions you require.
Also, even though my aircon has a recognised protocol that doesn’t need to be sent as raw data, I actually only use a handful of coides. What I do is to set the aircon to maximum cooling (in summer) then monitor the room temperature using a remote sensor. When it has reached the target temperature then I set the aircon to minimum cooling, so that it goes into idle mode.
More details here:
Pete.