Choosing a new bathroom suite can be one of the most challenging decisions you'll make when remodelling a bathroom, because there is a huge range of styles and materials to choose from. With bathtubs, one major question regards the materials. Cast iron tubs have been around for centuries and are still popular, but modern advances in plastics make acrylic baths an alternative to seriously consider.
Acrylic bathtubs are substantially cheaper than cast iron tubs, sometimes by as much as half. There are no ways around this fact; if you are refitting the bathroom on a budget, acrylic may be your only choice.
Both materials provide unique challenges. Cast iron tubs are very heavy, so if you're remodelling an upstairs bathroom, getting the tub up there will require several people and a lot of hard work. Be sure your upstairs floor can support the tub, by the way. Acrylic is lighter but sometimes comes with shower walls and other fixtures attached, so manoeuvring an acrylic tub indoors can be a challenge, too. It is also important to think about getting the old bathtub out. If it has been there for a while, chances are it is iron and will be difficult to get out and dispose of. Old acrylic baths can be cut up in situ and are easy to throw away.
Acrylic baths can crack, and iron baths can chip. If treated carefully, acrylic baths will require little maintenance and are easier to clean -- but they are a little brittle; it will not take much to end up with an ugly crack across the bath. Cast iron tubs will chip, but when they chip they can be re-coated with enamel, This, however, is a dirty and expensive task as it requires specialist respiratory equipment and harsh chemicals.
Due to their strength, cast iron baths will last longer. But there is a question whether the additional cost of buying one will outweigh how long it lasts.
The reason cast iron was such a popular material for tubs was because it will keep the bath water hot longer. Although an empty cast iron tub is cold to the touch, once hot water is in the tub the metal will heat up quickly and maintain the temperature better than acrylic.