For many UK households immersion heaters are an essential part of daily life. But how much do they actually cost to run? And more importantly, how can you reduce those costs without compromising comfort?
This guide from Backer Electric explores the real running costs of immersion heaters, the factors that affect energy usage, and practical ways to improve efficiency and save money.
What Is an Immersion Heater?
An immersion heater is an electric heating element installed inside a hot water cylinder. It heats water using resistive heating—electricity flows through the element, generating heat that warms the surrounding water. These systems are ideal for homes without access to gas and are compatible with renewable energy setups like solar PV.
Key Components:
- Heating Element: Made from copper, Incoloy, or titanium—chosen based on water hardness.
- Thermostat: Controls water temperature and includes a safety cut-off.
- Head: Designed to fit standard tank fittings.
Immersion heaters are easy to install, versatile, and a popular choice for energy-conscious households.
Running Costs: What to Expect
The cost of running an immersion heater depends on its power rating and usage duration. Most domestic units are rated at 3kW.
Example Calculation:
If electricity costs £0.29 per kWh:
3kW × 1 hour × £0.29 = £0.87 per hour
Using hot water for 3 hours daily would cost approximately £2.61 per day.
Typical Usage Patterns:
- Heating water once or twice daily
- Reheating based on household size and demand
- Controlled via timers or thermostats
What Affects Energy Consumption?
Several factors influence how much energy your immersion heater uses:
- Tank Size: Larger tanks require more energy to heat.
- Thermostat Setting: Higher temperatures increase electricity use.
- Insulation: Poor insulation leads to heat loss and frequent reheating.
- Usage Habits: Long showers or frequent hot water use drive up costs.
- Tariffs: Off-peak tariffs like Economy 7 can significantly reduce expenses.
Tips to Reduce Running Costs
Use a Timer
Set your immersion heater to run during off-peak hours (such as overnight on Economy 7). This can reduce energy bills by up to 50% when used alongside other efficient appliances.
Insulate Your Tank
Lagging your hot water tank and pipes helps retain heat, reducing the need for reheating. Backer Heatrod offers tank jackets and insulation solutions - contact us to learn more.
Set an Efficient Thermostat Temperature
Keep your thermostat between 55°C and 60°C. This range ensures safety, prevents bacterial growth, and avoids unnecessary energy use.
Regular Maintenance
In hard water areas, limescale build-up can reduce efficiency. Routine descaling and thermostat checks help maintain optimal performance.
Immersion Heaters vs. Other Heating Options
Immersion Heater vs. Gas Boiler
- Installation Cost: Lower for immersion heaters—no gas infrastructure needed.
- Carbon Impact: Reduced, especially when powered by renewable electricity.
- Suitability: Ideal for off-grid homes or as a backup system.
Immersion Heater vs. Solar Water Heating
- Solar systems can preheat water, reducing immersion heater usage.
- PV diverters allow excess solar energy to be stored as hot water.
- Long-term savings and environmental benefits are substantial.
Combining immersion heaters with solar PV offers one of the most sustainable ways to manage your household energy.
Need Expert Advice?
Unsure if your immersion heater is running efficiently? Interested in upgrades or integrating solar power?
Speak to a Backer Electric technical specialist for tailored advice on improving your hot water system.
Visit www.backer.co.uk to learn more or get in touch.