Electric or gas water heater: a practical comparison
Updated: 9/17/2026
Electric and gas water heaters can both be suitable, but the choice depends on the property and demand. Compare the whole system, not just the appliance price. Instantaneous heaters also have a flow limit: they do not deliver unlimited hot water per minute.
Connections and installation
An electric heater requires an electrical installation with suitable capacity and protection. Gas requires a suitable gas connection, combustion system and flue. An existing shared chimney may restrict model choice, so check the conditions before purchase.
Purchase and running costs
Request comparable quotations including the appliance, installation, necessary alterations and removal. Estimate running costs using current tariffs, your demand profile and the particular model's specifications. There is no general guarantee that one option will always be cheaper by a given percentage.
Hot-water supply and efficiency
A tank has a limited stored supply and takes time to reheat. An instantaneous model is limited by power and the difference between incoming and outgoing water temperatures. Compare energy labels for the same demand profile and the ability to supply several outlets simultaneously.
Safety and maintenance
Both systems need correct installation and maintenance. Electric heaters have electrical and pressure-related risks; gas additionally requires attention to combustion and flue gases. Set service intervals according to the manufacturer and responsible services. A CO alarm does not replace servicing.
Quick comparison
| Question | Electric | Gas |
|---|---|---|
| Infrastructure needed | Suitable electrical connection | Gas and suitable flue system |
| Water available | Depends on tank or power | Depends on model and flow |
| Running costs | Tariff and consumption | Tariff, consumption and efficiency |
| Maintenance | According to model and instructions | Appliance servicing and flue checks |
Environment and final choice
An electric appliance's impact depends on energy sources and consumption; gas has direct combustion emissions. Consider other technically feasible solutions if renewing the whole system. Professional assessment of connections, demand and maintenance is a better basis for choosing than declaring a universal winner.
