Do Cast Iron Bathtubs Retain Heat For Longer?
When discussing the merits of different bathtub materials, one claim consistently comes to the forefront: cast iron bathtubs retain heat for longer. But is this just a long-held belief, or is there science to back it up? The answer is a resounding yes, and it all comes down to a principle called thermal mass.
Understanding Thermal Mass
Thermal mass is the ability of a material to absorb, store, and release heat. Dense, heavy materials have a high thermal mass, while lightweight, less dense materials have a low thermal mass.
A cast iron bath is incredibly dense and heavy. When you fill it with hot water, the iron itself begins to slowly absorb the heat. This is why the tub might feel cool to the touch initially. However, once the iron is saturated with heat, it holds onto that energy for a very long time. It then begins to radiate the heat back into the water, effectively acting like a radiator itself and keeping the water at a consistent, comfortable temperature.
How Does This Compare to Other Materials?
Acrylic: Acrylic is a type of plastic and has a low thermal mass. It is a poor conductor of heat, which is why it feels warm to the touch almost immediately. It doesn't draw heat out of the water quickly, but it also doesn't store and radiate it back. The water will cool down at a more standard rate, primarily through evaporation from the surface.
Steel: Enameled steel baths are thin and have a low thermal mass. They heat up quickly but also lose that heat just as fast, often feeling cool and drawing warmth away from the water.
The Real-World Experience
The science translates into a noticeably more luxurious bathing experience. With a cast iron bath, you can indulge in a long, relaxing soak without the water turning tepid. There's no need to keep trickling in more hot water to maintain the temperature. This not only enhances your comfort but also saves water and energy in the long run.
So, the belief is true. If the idea of a long, uninterrupted, and blissfully warm bath appeals to you, then the superior heat retention of a cast iron bath makes it the undeniable best choice. Explore our range, from the compact Dryden Small to the grand Byron, to find your perfect heat-retaining centrepiece.