Blogs
Disadvantages of having a combination boiler in a four bedroom property
Thursday 16th January 2025
Carl O'Boyle BSc MRICS FCIOB MFPWS
1. Limited Hot Water Supply
• Issue: Combi boilers provide hot water on demand, meaning they can only heat one tap or shower at a time.
• Effect: In a larger household, with multiple bathrooms, this can lead to issues if more than one person needs hot water simultaneously.
2. Reduced Water Pressure for Multiple Outlets
• Issue: While combi boilers generally deliver good mains water pressure to a single outlet, the pressure can drop significantly when multiple outlets are in use.
• Effect: This can result in poor performance when using two or more showers or taps at the same time.
3. No Hot Water Backup
• Issue: Combi boilers do not store hot water. If the boiler fails, there is no backup supply of hot water.
• Effect: With a traditional system, a hot water cylinder provides stored hot water, giving temporary relief during a boiler failure.
4. High Demand Incompatibility
• Issue: For larger properties with higher hot water demand (multiple bathrooms or large bathtubs), combi boilers may struggle to keep up with the demand.
• Effect: A system with a hot water cylinder is better suited to handle simultaneous high-demand usage.
5. Boiler Size and Power Output Requirements
• Issue: A combi boiler must be powerful enough to heat both the central heating and provide instant hot water. In larger properties, this requires a higher kW-rated boiler, which can be less efficient when only heating is required.
• Effect: Traditional systems with a separate cylinder can have a lower-rated boiler for heating, improving efficiency and performance.
6. Incompatibility with Some Heating Systems
• Issue: Combi boilers are not compatible with solar thermal systems that rely on hot water storage.
• Effect: If you plan to install a renewable energy system, a traditional boiler with a cylinder is more suitable.
7. Potential for Delayed Hot Water Delivery
• Issue: Since combi boilers heat water on demand, there can be a delay in delivering hot water, especially if the boiler is far from the tap or shower.
• Effect: With a hot water cylinder, hot water is ready to be delivered immediately.
8. No Option for Immersion Heater Backup
• Issue: Traditional systems allow an immersion heater to be used as a backup source of hot water in case of boiler failure. Combi boilers do not offer this option.
• Effect: This increases reliance on the boiler for both heating and hot water.
Summary
In a four-bedroom property, particularly with multiple bathrooms and a high demand for hot water, the disadvantages of a combi boiler include limited hot water supply, reduced performance when multiple outlets are in use, and the lack of backup options. A traditional boiler with a cylinder is better suited for such homes, offering improved reliability, water pressure, and capacity for high-demand scenarios.
Would you like help calculating the cost of switching to a traditional system?
