The IRremoteESP8266 project supports a large number of air conditioner IR protocols. Perhaps one is similar to your A/C.
https://github.com/crankyoldgit/IRrcemoteESP8266/blob/master/SupportedProtocols.md
For example, some A/C use 88 bit codes (8 bits/byte * 11 bytes). Then 2 more bytes for 16 bit CRC/checksum equals a total of 13 bytes.