Lowered SRAM usage, improved using: http://arduino.cc/en/Reference/PROGMEM

From:
text   data    bss    dec    hexfilename
19858   1050    489  21397   5395Arduino_Thermostat.cpp.elf

To:
text   data    bss    dec    hexfilename
21086    248    569  21903   558fArduino_Thermostat.cpp.elf