🔌 How Does an Immersion Heater Work?
Expert insights from A&C Heating and Plumbing Ltd – London | Call 0779 559 5757
🔎 What Is an Immersion Heater?
An immersion heater is an electric heating element installed inside a hot water cylinder. It heats water directly, much like a kettle, and provides hot water independently of your central heating system.
Immersion heaters are commonly found in properties without gas boilers, or as a backup water heating option in homes that use solar or combi systems.
⚙️ How Does It Actually Work?
Immersion heaters are connected to your home’s electric circuit. When powered on, electricity flows through the element inside the hot water tank, warming the surrounding water. Most units come with:
- A thermostat to control the water temperature
- A timer to set operation hours and reduce energy waste
- Insulation jackets to keep water warm longer
Water is heated from the bottom up, and once it reaches the set temperature, the thermostat shuts the element off automatically.
💡 You can still use an immersion heater even if your boiler is broken — that’s why many homeowners treat it as a reliable backup system.
🧰 Benefits of an Immersion Heater
- ✅ Works independently of gas or boiler system
- ✅ Ideal for homes with solar thermal systems
- ✅ Simple electric setup
- ✅ Emergency backup if your boiler fails
- ✅ Can be connected to off-peak electricity for savings
🚫 Common Immersion Heater Problems
- Limescale buildup on the heating element
- Faulty thermostats causing overheating
- Blown fuses or tripped switches
- Noisy operation due to sediment
🔧 We offer fast and affordable immersion heater repairs
🆚 Immersion Heaters vs. Other Heating Systems
| Feature | Immersion Heater | Gas Boiler | Combi Boiler |
|---|---|---|---|
| Energy Source | Electricity | Gas | Gas + Water |
| Water Storage | Requires cylinder | Optional | No cylinder |
| Backup Capability | ✅ Yes | ❌ No | ❌ No |
| Ideal For | Flats, backup | Full heating | Instant hot water |
🔗 Discover more about solar thermal integration
💡 How to Use an Immersion Heater Efficiently
- ✅ Only turn it on when needed (use a timer!)
- ✅ Keep the cylinder insulated
- ✅ Set the thermostat to ~55–60°C
- ✅ Schedule periodic servicing to avoid limescale buildup
📍 Servicing & Repair Across North & West London
At A&C Heating and Plumbing Ltd, we specialise in immersion heater installation, repair, and upgrades across:
- Ealing
- Islington
- Harrow
- Willesden
- Camden
📞 Call us on 0779 559 5757 or request a free quote online
❓ Frequently Asked Questions
Can I use my immersion heater without the boiler?
Yes! That’s one of its main advantages — it works independently and is ideal as a backup.
Is it expensive to run an immersion heater?
It can be if left on continuously. Use a timer and off-peak electricity to keep costs low.
How long does it take to heat the water?
On average, 1–2 hours depending on the cylinder size and water temperature.
📞 Need Help With Your Immersion Heater?
Whether it’s not working, heating slowly or tripping your fuse board — we’re here to help.
👉 Call 0779 559 5757
👉 Or book immersion heater repair online