Short definition

Residential bathtubs come in four main materials: enameled cast iron, pressed steel, acrylic, and fiberglass-reinforced plastic. They differ on weight, durability, heat retention, noise, and cost. Cast iron lasts a lifetime; acrylic dominates modern remodels; pressed steel and fiberglass live mostly in budget and rental construction.

What it is

The four-way comparison:

  • Enameled cast iron — 250 to 500-plus pounds. Most durable, retains heat, quietest under running water. Genuinely a lifetime fixture. Hardest to install (you’ll need help moving it). $700 to $4,000+.
  • Pressed steel (enameled) — 60 to 100 pounds. Inexpensive, but conducts heat away from the bath water (cools fast) and rings noisily during fill. $200 to $700.
  • Acrylic with fiberglass backing — 60 to 80 pounds. Durable enough, warm to touch, comfortable, available in every shape and size. Most popular modern residential choice. $400 to $2,500.
  • Fiberglass-reinforced plastic (FRP / gel-coat) — 30 to 60 pounds. Cheap; gel-coat surface dulls and crazes after 5 to 10 years. Common in rentals and budget construction. $200 to $500.

Any of these can be configured as alcove (three-walled), apron (skirted, drop-in over framing), or freestanding.

Why it matters to a homeowner

Material choice locks in trade-offs you’ll live with for decades.

If you have a pre-1950 WA home with the original cast-iron tub still in place, refinishing typically beats replacing — the tub is worth keeping for character, sound damping, and the demolition cost of removing 350 pounds of cast iron is real (most contractors break the tub apart with a sledgehammer rather than carry it out intact).

For a modern remodel, acrylic is the default for the secondary bath; cast iron earns its premium in the primary bath of a luxury remodel where you’ll feel the heat retention and quiet operation every day.

For a rental property or budget remodel, pressed steel or fiberglass keeps you under $1,000 on the tub itself — accept the shorter service life and louder fill.

For a heavy-use family that wants one tub to outlast the kids, cast iron is the only material that genuinely doesn’t have a service life.

Common failure modes

  • Cast iron — chipped enamel from a dropped bottle exposes iron, which rusts. Refinish or accept the cosmetic spot.
  • Pressed steel — same chip-and-rust failure mode but worse: thinner enamel, faster substrate corrosion.
  • Acrylic — surface scratches; most polish out. Harsh cleaners discolor over time.
  • Fiberglass — gel-coat dulls, crazes, develops a chalky feel after 5 to 10 years. Resurfacing extends life modestly; replacement is usually the right call.

Common variants

  • All four materials work as alcove, drop-in, or freestanding tubs.
  • “Whirlpool” or “air-jet” features can be added to any material — a separate axis from the basic material choice.
  • Resurfacing (also called reglazing) applies to all materials, but is most economical and longest-lasting on cast iron.