Boilers Explained

Combi boilers don’t use water tanks. They instead heat water as it runs from the street mains into homes. When a hot water tap is turned on, the boiler fires up and the water is heated as it runs from the street mains and into household pipes. The water pressure generated to taps and shower heads is high because it feeds straight from the mains.

Water Pressure

Combi boiler systems take water in directly from the main so the pressure is stronger than conventional or heat-only boilers, which use hot and cold water tanks built into lofts. Water feeds down through the pipes and into the taps and shower heads. The water pressure of conventional boilers is weaker because it’s limited to what gravity can generate.

Save Energy

Conventional water boilers automatically heat water up twice per day, once in the morning and once at night, which wastes energy.

Twice the Work

Combi boilers do two jobs at once: They provide central heating and water on demand. Once the hot water tank in conventional units runs out, the boiler needs time to heat more hot water.

Save Money

Conventional boiler systems require more maintenance that combi boilers require because they have two units and water tanks. Combi boilers have only one unit, which cuts maintenance costs in half and speeds up installation.

Save Space

Conventional boiler systems occupy floor and wall space with large water tanks and long, complicated, pipe networks. Combi boiler units are easily mounted onto walls or floors and can fit into tighter areas. They are ideal for small houses and apartments.

Simpler Installation

Combi boilers cost less to install than conventional boiler systems because they require less pipework and don’t need to be connected to external water tanks.

Combi boilers don’t produce enough hot water to run multiple showers at once. Larger homes with multiple bathrooms require conventional boiler systems with water tanks that can support multiple showers at once.

Unlike conventional systems, combi boilers are susceptible to hard water​, or water containing high amounts of the minerals magnesium and calcium. Hard water creates many household problems, including:

• pipe clogging from scale deposits
• Faster wearing of appliances

Lastly, because the water supply is heated straight from the mains, it relies on the mains water pressure to move the water around your home. If you have poor water pressure in your area, then a combi boiler might struggle to keep enough pressure in your system to move water around it.

The overall cost of a combi boiler is equal to the sum of the supply costs and installation costs. The total amount depends on the brand, model, and any heating system component parts installed.

The cost of replacing an old combi boiler with a new one is lower than the cost of converting from a conventional boiler because no pipeworks need to be fitted and no storage tanks need to be removed.

The best time to install a combi boiler system is in the spring or summer. Plumbers and electricians command higher rates in the cold months because their services in higher demand. Installation during general refurbishments is also a good idea, as pipework may require tearing up floors and carpets.