Will your towel warmer be replacing a radiator?
You should try and choose a towel warmer of a similar width to the replaced radiator. A wider towel warmer will require re-plumbing, although a narrower towel can usually be adapted to fit using valve tails.
Do you want your towel warmer to work independently of your central heating system?
You can fit an electric conversion kit, together with a hardwired On/Off switch outside the bathroom. Or you could fit a thermostatic switch, which regulates the rail’s temperature in accordance with the bathroom’s temperature.
Better still, both kinds of electric kit come with a T Piece, which will give you extra flexibility. When switched on, it will heat your towel warmer using the central heating, and when switched off, your towel warmer is heated by the element.
A white towel warmer gives out slightly more heat than an identically sized chrome towel warmer.