Steel vs Aluminium vs Cast Iron Radiators
Comparing radiator materials for UK homes — heat output, weight, response time, cost, aesthetics and compatibility with heat pumps.
Side-by-Side Comparison
| Property | Steel Panel | Aluminium | Cast Iron |
|---|---|---|---|
| Heat-up time | 10-15 minutes | 5-8 minutes | 30-45 minutes |
| Cool-down time | 15-20 minutes | 10-12 minutes | 45-90 minutes |
| Output per section (W) | 120-160 (per panel) | 180-220 | 40-80 (larger sections) |
| Weight (600x1000mm) | 15-25 kg | 8-14 kg | 40-70 kg |
| Water content | Moderate | Low | High |
| Cost (600x1000mm) | £60-150 | £120-300 | £300-800 |
| Heat pump suitability | Good (if oversized) | Excellent | Poor |
| Lifespan | 15-25 years | 20-30 years | 50-100+ years |
| Aesthetics | Standard/modern | Contemporary | Heritage/period |
Pros and Cons
Steel Panel Radiators
Pros
- + Cheapest option by far
- + Huge range of sizes available
- + Widely stocked at merchants
- + Good heat output for the price
- + Easy to install and replace
Cons
- - Susceptible to corrosion
- - Standard appearance
- - Shorter lifespan
- - Moderate heat-up time
- - Limited low-temp performance
Aluminium Radiators
Pros
- + Fastest heat-up time
- + Best output per kg
- + Lightest — easy to wall-mount
- + Ideal for heat pump systems
- + Modern, sleek designs
Cons
- - More expensive than steel
- - pH sensitive (galvanic corrosion)
- - Cools quickly when system off
- - Cannot mix freely with other metals
- - Less availability at UK merchants
Cast Iron Radiators
Pros
- + Outstanding lifespan (100+ years)
- + Retains heat long after system off
- + Beautiful period aesthetics
- + Extremely robust and durable
- + High radiant heat (comfortable)
Cons
- - Very expensive
- - Extremely heavy (wall mounting difficult)
- - Very slow to heat up
- - High water volume (inefficient cycling)
- - Not suitable for heat pumps
UK Cost Comparison (2026 Prices)
For heating a typical 3-bedroom house (8 radiators, mixed sizes):
| Cost Element | Steel Panel | Aluminium | Cast Iron |
|---|---|---|---|
| 8 radiators (supply) | £500-1,000 | £1,000-2,200 | £2,400-6,000 |
| Valves & TRVs | £120-200 | £120-200 | £200-400 |
| Installation labour | £600-1,000 | £600-1,000 | £800-1,400 |
| Total | £1,220-2,200 | £1,720-3,400 | £3,400-7,800 |
When to Choose Each
Choose Steel When
- Budget is the priority
- Standard gas boiler system
- Quick replacement needed
- Rental or investment property
Choose Aluminium When
- Heat pump system
- Fast response needed
- Lightweight wall mounting
- Energy efficiency is key
Choose Cast Iron When
- Period property restoration
- Heritage aesthetic required
- Long heat retention wanted
- Lifetime product investment
Related Calculators
- Radiator Sizing Calculator — calculate radiator output needed for each room
- Radiator BTU Calculator — convert between watts and BTU for radiator selection
How We Calculate This
Frequently Asked Questions
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Last updated: April 2026
All calculations are estimates. Verify with your supplier.