How to Choose the Right Size or Watt Heating Element for Your Heated Towel Rail
Last updated: January 2026
Choosing the right wattage element is the most important decision when converting your towel rail to electric or dual fuel. Too small and your towels won't dry properly. Too large and you'll waste energy. This guide makes it simple.
⚡ Quick Answer
Multiply your towel rail's water volume (litres) by 30 to get the recommended wattage. For example: 10 litres × 30 = 300W element. Don't know your volume? Use our volume calculator.
📊 Element Wattage Guide
| Towel Rail Size | Water Volume | Recommended Wattage | Heat-Up Time |
|---|---|---|---|
| Small (up to 600mm) | 3-6 litres | 150W | ~30 mins |
| Medium (600-1000mm) | 6-12 litres | 300W | ~40 mins |
| Large (1000-1400mm) | 12-20 litres | 600W | ~45 mins |
| Extra Large (1400mm+) | 20+ litres | 800-1200W | ~50 mins |
💡 These are guidelines - use the volume calculation for accurate sizing
🔌 Choose Your Element Type
Standard Element
From £24.99
- Simple on/off operation
- Fixed temperature (~60°C)
- Requires separate timer
- Best for: Guest bathrooms
Thermostatic Element
From £54.99
- Adjustable temperature dial
- Built-in thermostat (30-60°C)
- Auto cut-off saves energy
- Best for: Main bathrooms
WiFi Smart Element
From £79.95
- Phone app control
- Weekly schedules
- Alexa & Google compatible
- Best for: Smart homes
⚠️ Common Mistakes to Avoid
- Oversizing the element – A 600W element in a small rail wastes electricity and can overheat
- Undersizing the element – A 150W element in a large rail will never get properly warm
- Forgetting the inhibitor – Always add corrosion inhibitor to prevent rust
- Overfilling – Fill to 90% capacity only (leave expansion room)
🎯 What's Your Main Purpose?
Just Warming Towels?
A lower wattage (150-300W) is fine. Your towels will be warm and dry without heating the room significantly. Great if you have other heating in the bathroom.
Heating the Bathroom Too?
Go higher (400-600W+). If your towel rail is the primary heat source, you'll need enough output to warm the whole room. Consider room size in your calculation.
🔥 Consider Dual Fuel
Want the best of both worlds? A dual fuel setup lets you use central heating in winter and switch to electric in summer — warm towels year-round without running your boiler.
Explore Dual Fuel Options →❓ Frequently Asked Questions
Can I use a higher wattage element than recommended?
Yes, but it's wasteful. The element will cycle on/off more frequently, and you'll use more electricity than needed. Stick to the recommended wattage for best efficiency.
How do I know my towel rail's water volume?
Check the product specifications or use our volume calculator. You'll need the width, height, and number of bars.
Do I need an electrician to install?
Yes. Electric heating elements must be installed by a qualified electrician and connected to a fused spur. This is a legal requirement in the UK.
What's the running cost?
A 300W element running 2 hours/day costs approximately £5-6 per month (at 30p/kWh). WiFi elements with timers help reduce costs by only heating when needed.
Still Not Sure Which Element You Need?
Our team can recommend the perfect element for your towel rail
