It is possible to replace your cast iron bath with a new one made of the same material, but more modern in styling. However, these baths are expensive and very heavy indeed. Carrying one into the bathroom and fitting it requires considerable strength (you’d need at least one strong helper) as well as care.
There are other snags about enamelled cast iron baths. They normally have a slippery base that can make them dangerous to use — particularly by the very young and the elderly, though some are available with a non-slip surface. Furthermore, the material of which they are made rapidly conducts the heat away from the water and while this didn’t matter too much in the days when energy was plentiful and cheap, large amounts of hot water cost rather more today. Replacing A Bath - The Alternatives One economical alternative is an enamelled pressed steel bath. This is lighter and cheaper than enamelled cast iron but can be more easily damaged in storage or installation. For do-it-yourself installation a plastic bath is the obvious choice. These are made of acrylic plastic sheet, sometimes reinforced with glass fiber. They are available in a number of attractive colours and, as the colour extends right through the material of which they are made, any surface scratches can be easily polished out. They are light in weight and one man can quite easily carry one upstairs for installation. The plastic of which they are made is a poor conductor of heat which means that they are both comfortable and economical to use. Many of them have a non-slip base to make them safe. But plastic baths do have their snags. They are easily damaged by extreme heat. You should be beware of using a blow torch in proximity to one and a lighted cigarette should never be rested, even momentarily, on the rim. A fault of early plastic baths was their tendency to creak and sag when filled with hot water and, sometimes, when you got into them. This has now been overcome by the manufacturers who provide substantial frames or cradles for support; but these frames must be assembled and fixed exactly as recommended. A combined plastic waste and overflow assembly is likely to be the choice nowadays for any bath, and is obligatory with a plastic bath. If a rigid metal trap is used with a plastic bath, the material of the bath could be damaged as hot water causes unequal expansion.