There are many different types of boilers and central heating systems available on the market and it can sometimes be difficult to decide which type is best suited for your home.
Here are a few things to think about when deciding which boiler is the right one for you.
What Is a Boiler?
A boiler is essentially a furnace, generally fuelled by gas or oil. Renewable fuels such as wood pellets/chippings or solar are also becoming increasingly popular. The boiler operates using combustion, burning carbon-based fuel with oxygen, in order to produce heat. The exhaust fumes of carbon dioxide escape through the flue (a type of chimney). The boiler heats water, which is then moved by an electrically powered pump into radiators and to your taps.
How Do Boilers Heat Your Home?
A domestic gas boiler consists of a sealed combustion chamber, in which a valve allows small jets of gas to be released into the chamber and an electric ignition system then sets them alight. These jets of gas fire onto a heat exchanger, that plays onto a pipe carrying cold water. The heat exchanger allows heat from one medium to pass to the other without the two mediums ever coming into direct contact with each other.
The heated water is pumped through into a radiator, which comprises of a copper pipe that bends around several times inside its metal covering (the outside of the radiator). The large surface area of a radiator enables it to efficiently heat the room. Traditional radiators are either on or off, there is no way of controlling the temperature, whereas thermostatic radiators allow you to control the temperature in the room.
In order to regulate the temperature in any home, a thermostat can be installed. This is an electronic programmer attached to the heating system, which can be programmed to switch on automatically at certain times of the day, such as first thing in the morning or half an hour before you arrive home from work to make sure the house is warm. Wall thermostats regulate the room temperature; when it rises above a certain level, the thermostat will automatically switch the circuit off and it will also switch it back on when the room gets too cold.
Different Types of Boilers
The 3 most common types of boiler include the conventional, system and combi. Newer boilers will also use condensing technology.
These are the most traditional type of boiler; they heat hot water in a large cylinder which is then used for the hot taps and they also send heated water to the radiators to heat the home.
- Conventional boilers are generally better suited to larger homes with more than one bathroom, as you can run multiple hot taps at the same time, provided that there is sufficient hot water in the cylinder.
- An immersion heater can be fitted into the boiler, for use in the case of the boiler breaking down.
- Extra space is required for the 2 separate tanks; 1 for hot water and 1 for cold water. They are usually stored in the loft.
- There is a limited capacity of hot water; once it has run out you will have to wait for it to heat up again.
- Programmable controls are essential to ensure the water is heated for when it is needed.
System boilers operate in a very similar manner to the conventional boiler; water is heated and stored in a hot water cylinder.
- The system boiler has many of the parts needed for the conventional heater already built in, therefore installation is easier.
- There is no need for an extra separate tank.
- The tank can be stored in an airing cupboard instead of the loft.
- Multiple hot taps can be used at the same time in different bathrooms.
- Hot water is of limited capacity.
These are probably the most popular type of boiler and are well suited to smaller homes and flats, supplying limitless hot water on demand. When the hot water tap is turned on, a valve is opened that lets the water escape through a network of pipes back to the boiler. The boiler then detects that the valve has been opened and instantly fires up to heat the water. Combi boilers also heat the radiators.
- Hot water is limitless and supplied on demand.
- This can be more economical as you only heat the water you use.
- No need for a separate hot and cold water cylinder and no need for extra storage space.
- Hot water can only be used in one place at any time.
- If you are using the taps in the bathroom and the kitchen at the same time, the flow of water may be considerably reduced.
- Central heating will be paused when using hot taps.
Boilers that rely purely on combustion often lose a lot of heat through the flue, via the exhaust gases. This is wasted energy. A combination condensing boiler is a more complex system whereby the flue gases (waste exhaust) pass through a heat exchanger that warms the cold water returning from the radiators. Newer boilers usually incorporate condensing technology, making them far more energy efficient. Older boilers – those over 15 years old – will not use condensing technology and therefore will not be as efficient.
Different fuel types
The most commonly used fuel for boilers is natural gas. A gas boiler operates as previously described above.
This works in a similar manner to gas. An oil-fired boiler heats the water, providing hot water for the taps as well as for the radiators throughout the home. The oil supply is stored in a tank which has to be delivered. Both heat-only and combination, condensing boilers are available on the market. Most oil boilers use kerosene or 28 second fuel as it is also known, as this is a lighter and cleaner fuel and the most commonly used in UK homes. It is also less likely to form crystals that stop it flowing in cold weather. Crystals will only begin to start forming when temperatures drop to around -39c. An alternative to kerosene is gas oil, also known as 35 second fuel or red diesel. This is a much heavier oil generally and a boiler would have to be configured specifically for it. This is fairly uncommon for modern boilers.
- An efficient source of energy.
- Oil prices on the market may fluctuate.
A biomass heating system is also classed as carbon neutral, renewable energy. Biomass fuel generally comes in the form of wood pellets or logs; these emit the same amount of carbon dioxide that was absorbed while the plant was growing. Wood pellets, chips or logs are burnt in the boiler to heat the water and provide central heating.
- Lower price.
- Lower carbon footprint.
- Possibility of financial support from the renewable heat incentive.
- Higher maintenance; some have self-cleaning systems to clean out the ashes but others have to be swept out manually at regular intervals.
- A flue that meets regulations for wood-burning appliances must be installed.
- Sooty deposits can build up inside the flue.
- The boiler is larger than its oil/gas counterparts and requires more space. Extra space is also required to store the fuel.
- Wood has to be seasoned before it can be burned.
- Planning permission may be needed to install a biomass boiler.
Solar thermal systems
Solar panels – also known as collectors – are fitted to the roof to collect heat from the sun, to heat water stored in a cylinder, intended for domestic use. The 2 types of solar panels include evacuated tubes and flat plate collectors. A boiler or immersion heater is usually used as a back up to further heat the water if needed.
- Once installed, energy costs are considerably reduced as the sun is free!
- Lower carbon footprint.
- You will need somewhere that receives direct sunlight for the main part of the day. In the cold months you won’t get much energy from the solar panels.
- Your current boiler system might not be compatible with solar water heating – if this is the case you will need a new boiler.
You will now have some understanding of the different types of boilers and which would be right for your home. Browse the range of boilers at Huws Gray online today, or phone one of our branches for further advice from the experts.