TL;DR: Choose cast iron if you want a solid, long-lasting period bath and your floor can take the weight; choose acrylic if you need a lighter, cheaper bath or a shape cast iron doesn't come in.
- Weight: a cast iron bath is well over 100kg empty and can put 400kg+ on the floor when full, so the floor needs checking. Acrylic is roughly 20kg to 40kg.
- Warmth: acrylic feels warm straight away; cast iron takes some heat at first, then holds it. Both make a comfortable bath.
- Durability: cast iron enamel resists scratches but can chip (chips can be repaired); acrylic can scratch, but light marks often polish out.
- Cost: our acrylic freestanding baths start at £1,184 and cast iron at £2,995, and acrylic is cheaper to fit.
- Style: cast iron for classic roll tops and slippers; acrylic for shower, corner and unusual shapes. Both can be painted.
Choosing between a cast iron vs acrylic bath is one of the first big decisions in a bathroom renovation. Both will hold water and both can look good, but they behave very differently once they are in your home. They differ in weight, in how they feel to the touch, in how they age and in what they cost to buy and fit.
We supply both cast iron and acrylic baths, so this is a straight comparison, including the situations where each one makes more sense.
Cast iron vs acrylic bath at a glance
| Cast iron | Acrylic | |
|---|---|---|
| Material | Cast iron shell with a hard vitreous enamel inside | Acrylic sheet, usually reinforced underneath with resin and glass fibre |
| Weight (empty) | Heavy: well over 100kg for a typical freestanding bath | Light: roughly 20kg to 40kg for a standard 1700mm bath |
| Feel | Cool to the touch at first, very solid | Warm to the touch straight away, can flex slightly if poorly supported |
| Surface | Very hard and scratch resistant, but can chip if something heavy is dropped | Softer, can scratch, but light scratches can often be polished out |
| Style | Classic roll tops, slippers and double-ended shapes; outside can be painted | Huge range of shapes, including shower baths and corner baths |
| Cost | Higher to buy and to fit | Lower to buy and to fit |
Heat retention: which keeps the water warm?
This is where most comparisons oversimplify. Acrylic is a natural insulator, so it feels warm the moment you touch it and it does a good job of keeping bath water warm.
Cast iron works differently. It is a dense metal with a lot of mass, so when you first run the bath some of the heat from the water goes into warming the bath itself. Once it is up to temperature, that mass holds warmth steadily and the bath feels reassuringly solid. A simple trick is to run the hot tap first for a minute or two to take the chill off before filling.
In practice, both types make a warm, comfortable bath. The difference is more about feel than physics: acrylic is warm to the touch, cast iron is heavy and still.
Weight and floor loading
This is the practical question that matters most with cast iron. As an example, the Imperial Waldorf single-ended cast iron bath weighs 132kg empty and holds 225 litres. A litre of water weighs about a kilo, so once it is full and someone is in it, the floor could be carrying well over 400kg, concentrated through four feet.
Most sound timber floors can take that, but it needs checking rather than assuming. Before ordering a cast iron bath for an upstairs bathroom, your fitter should check:
- Joist size, span and direction relative to where the bath will sit.
- Notches and holes cut into joists over the years for pipes and cables, which are common in older houses.
- The condition of the floor, including any rot or previous water damage near the old bath or WC.
- Spreading the load, for example with a suitable board under the feet, and whether a structural engineer should take a look.
Getting it up the stairs is part of the plan too. A cast iron bath needs several people to carry and position it, which is one reason fitting costs more than for acrylic.
An acrylic bath weighs a fraction of this, which is its biggest advantage in a small upstairs bathroom with a weak or heavily notched floor.
Durability and how they age
Cast iron baths are famously long-lived. Reclaimed Victorian cast iron baths are still in use today. The enamel is very hard, so everyday use and cleaning will not scratch it the way they can scratch acrylic. The weak point is impact: drop something heavy and the enamel can chip. Small chips can be repaired and a worn bath can be re-enamelled by a specialist.
Being hand cast, a cast iron bath can show small ripples, dimples or specks in the enamel. Imperial describes these as part of the character of the material rather than faults.
Acrylic is softer. It can pick up scratches and dull over time, although light marks can often be polished out. A well-made, well-supported acrylic bath will give years of service. A thin or poorly supported one can flex under weight, which puts strain on the sealant around the edges.
Whichever you choose, clean it with non-abrasive products. Scouring pads and harsh cleaners will damage either surface.
Cast iron vs acrylic bath prices
Acrylic is the budget-friendly option, both to buy and to install. Here is how our freestanding baths compare, including VAT at the time of writing:
| Acrylic freestanding | Cast iron freestanding | |
|---|---|---|
| Starting price | £1,184 (Una) | £2,995 (Waldorf) |
| Typical price | £1,500 to £2,100 | £4,000 to £8,000 |
| Slipper bath example | Dora double ended slipper, from £1,840 | Ritz 1700 slipper, from £3,995 |
| Fitting | Lighter and quicker to fit | Needs several people and a floor check |
A standard panelled acrylic bath costs far less again, from £261. Freestanding baths also usually need freestanding or wall-mounted taps, an exposed waste and possibly flooring that runs right under the bath, all of which add to the total.
The fairest way to compare is on the whole job rather than the bath alone, which is why every quote we give is itemised.
Style: where cast iron comes into its own
If you want a traditional roll top, a high-backed slipper or a double-ended bath with a proper weight to it, cast iron is the real thing. Imperial cast iron baths are supplied primed and ready to paint, so the outside can be any colour you like, and a RAL colour painting service is available. Feet come in Chrome, Polished Nickel, Brushed Nickel, Brass plated, Gold, Cast iron or White enamelled, so you can match them to your taps.
Popular choices include the Westminster cast iron freestanding bath and the Radcliffe cast iron bath. For something more contemporary, the Radison with a polished aluminium skirt gives a cast iron bath a metallic finish. You can see the full range in our baths collection and our guide to the best cast iron baths, and pair it with a freestanding bath shower mixer in a matching finish. Our guide to bathroom tap finishes explains how to choose one.
Acrylic wins on shape variety. If you need a shower bath, a corner bath or a very specific size to fit an awkward room, acrylic may be the practical answer. Our own Tilelyte Bath Collection of acrylic baths includes roll top, slipper, boat, textured, fluted and back-to-wall designs, and every one can be hand-painted to order in almost any colour.
Are acrylic baths good?
Yes. A good acrylic bath is warm to the touch, light enough for any floor, and comes in almost any shape, and with care it will last for many years. Quality varies, so look for thick sanitary-grade acrylic that is reinforced underneath, and a bath that is properly supported so it doesn't flex. Our Tilelyte Bath Collection baths are 5mm sanitary-grade acrylic, and Carron's Carronite is a reinforced acrylic with a 40-year warranty. See our acrylic baths and our acrylic freestanding baths guide.
Why we offer both
We supply cast iron and composite baths from Imperial Bathrooms, a UK maker, alongside our own Tilelyte Bath Collection of acrylic baths. Cast iron suits you if you want a bath that feels solid, suits a period home and will last for decades. Acrylic suits lighter floors, tighter budgets and anyone who wants a textured or fluted design. Both can be painted to suit the room. If your floor, budget or layout points one way, it is better to know before you set your heart on a particular bath.
Frequently asked questions
Is cast iron better than acrylic?
Not in every way. Cast iron is harder-wearing, feels more solid and lasts for decades, but it is heavy and costs more. Acrylic is lighter, warmer to the touch, cheaper and comes in more shapes. Choose by your floor, budget and the style you want.
Is a cast iron bath too heavy for an upstairs bathroom?
Usually not, as long as the floor is sound. Joist size, span, condition and any old notches need checking before you order, and the load may need spreading under the feet.
Does a cast iron bath keep water warmer than acrylic?
Not dramatically. Cast iron takes some heat from the water at first, then holds warmth well. Acrylic insulates and feels warm straight away. Both make a comfortable bath.
Can I paint a cast iron bath?
Yes. Imperial cast iron baths come primed and ready to paint in any colour, with a RAL colour painting service available if you would rather not do it yourself.
Can chipped enamel be repaired?
Yes. Small chips can be repaired and a tired bath can be re-enamelled by a specialist, which is one reason cast iron baths last so long.
Book a free consultation
If you are torn between cast iron and acrylic, come and talk it through. Every project starts with a free one-to-one consultation, where we look at your room, your floor and your budget, followed by a clear, itemised quote. Visit our showroom at 32 Manor Park Rd, Birmingham B36 0DJ (Tuesday to Saturday, 9am to 5pm), call 0121 794 2553 or book your free consultation online.