Tyson's favourite colour is red, but most of the larger items he buys - such as a bed (okay technically the bed sheets are blue, the bed is metal) and the carpet - tend to be blue.
He does this on purpose. By making the larger objects blue it means he can buy more red, smaller, objects - like clothes, mugs, pillow, et cetrera - and still have a good/clean colour contrast in the room; which is important, due to the sometimes overwhelming colours brought into his vision by his Synesthesia.