What are Combi (Combination) Boilers?
Combination boilers, often called combi boilers, are an increasingly popular choice for home heating and hot water. They combine both functions into one compact unit, eliminating the need for a separate hot water cylinder or cold water storage tank. Unlike older systems, combi boilers provide hot water on demand and don’t require pre-heating, making them more efficient and space-saving.
FAQs
The three main types of boilers are:
- Combi Boilers: Provide hot water on demand and don’t require a separate water tank.
- System Boilers: Have a built-in water storage tank, making them suitable for homes with high hot water demand.
- Conventional Boilers (Regular Boilers): Include a separate water tank in the loft and a hot water cylinder, suitable for larger homes with multiple bathrooms.
Combi boilers are best suited for homes with limited space and moderate hot water demand. They are perfect for small to medium-sized homes with one bathroom, but may not be the best option for larger properties with multiple bathrooms, where system boilers could be a better choice.
Boiler size is determined by kilowatt (kW) output. A higher kW rating means the boiler can meet greater demands for heating and hot water. Here’s a quick guide to combi boiler sizing:
- 2-Bedroom House: 26 kW for one bath, 29 kW for two.
- 3-Bedroom House: 29 kW for one bath, 35 kW for two.
- 4-5 Bedroom House: 35 kW for homes with multiple bathrooms.
Combi boilers draw water directly from the mains. When hot water is needed, gas is burned in the boiler to heat the water via a heat exchanger. When your thermostat detects a temperature drop, the boiler kicks in to heat your home, switching off when the set temperature is reached to save energy. However, combi boilers can only heat water for taps or the central heating system at one time.
A well-maintained combi boiler can last 10-15 years. Higher-quality models often come with longer warranties, which can indicate their durability. Although cheaper boilers may seem like a bargain, they can require frequent repairs, making them costlier in the long run.
The installation time for combi boilers varies, with simple replacements taking around 4-6 hours, while conversions from older systems can take 2-3 days. UK regulations mandate that gas boilers must have at least 92% ErP efficiency and include at least one energy-saving feature.
