Instead of storing raw codes, you could also try using pronto codes for some of your IR devices. The pronto codes will take up less space than the longer raw codes.
First, the long form Pronto codes and the irRemote library raw buffer both use 2 byte values to store on and off times, so they should in most cases be approximately the same length (Pronto codes have 8 bytes of additional header). (Of course if you stored Pronto codes in hex format they'd be much longer).
And in order to use irRemote to send the pulses, it will need the raw buffer values in its expected format.
I suspect one could translate stored Pronto codes into raw values in the sensuator node before calling the library, but if the Pronto code is no shorter, why not simply store the raw codes instead?
It might even be possible to modify the irRemote library to send values using timing directly from PROGMEM, and not even need the RAM to buffer the raw codes (when only sending).