Every house has a boiler but not all boilers are equal. What type of boiler do I have is a question you may be asking yourself if you are thinking of a boiler replacement.
Domestic boilers come in three different types.
- Combi boilers
- System boilers
- Regular boilers
Combination boilers or combi boilers as they are more commonly known. Account for more than half of new boiler installations each year in the UK. Combi boilers are a combination of two boilers. A single unit that provides the heat for both your hot water and your heating. No need for any hot water storage cylinders or tanks in the loft. They heat the water straight from the mains whenever demand at the taps. This means you have unlimited hot water whenever you may need it.
- Compact choice no need for tanks or cylinders
- Unlimited instant hot water when you need it
- Water delivered from mains
- Ideal for small to medium properties
System boilers. A system boiler heats your radiators and also the stored hot water and fed from the mains. System boilers are somewhere between a combi boiler and a regular boiler. They have components built into the boiler itself such as pump and expansion vessel. If you have a hot water cylinder but no tank in your loft then chances are you have a system boiler.
- Suitable for larger properties with a bigger demand for hot water
- Can use many outlets at the same time
- No need for a cold water tank in the loft
- Built-in components such as pump and expansion vessel
Regular boilers, conventional or heat only as they are also known. Fed by two tanks situated in the roof space. One of these, the cold water storage tank draws cold in from the mains. The other, smaller tank feeds the boiler system. Also manages the expansion during the heating up of the water. Many older systems designed in this way. A regular boiler is a good option if it is a like for like swap on an older system. Old radiators and pipework may not withstand the added pressures of a sealed system. A regular boiler is also a good solution if the water pressure is low, pumps etc
- Suitable for larger homes with higher demands
- Good choice on an older system as a like for like swap, minimal alterations
- Back up immersion heater
Usually, a replacement boiler will be a like for like swap. But is this the right thing to do?
If you have an average-sized house with 1-2 bathrooms, then a combi would be a good choice.
If you have a larger house with 2+ bathrooms. Then a System boiler with unvented hot water storage would be the best option.
If you live in an older house with an old heating system, you may be better with a regular or heat-only boiler. This is because the old pipes and radiators have never been exposed to pressurised water. And may develop leaks down the line. This is unless you’re planning on modernising the heating system altogether. Eg. back boiler and copper cylinder upgrade to combi
When choosing which boiler brand to use there may be a number of decisions guiding this decision. Such as reputation, reliability, cost, length of warranty and cost of spares.
The boiler brands we offer through our website are;
- Worcester Bosch
If you would like us to quote for a boiler that is not on our website then give us a call or drop us an email.
To find out what the users of Which had to say about boiler brands then here is their survey results.
A condensing boiler has all the same components as a non-condensing boiler. The difference is the amount of heat that can be used from the same amount of fuel burnt.
- If your boiler was installed after 2005, chances are it is a condensing model.
- The boiler manual will have it in the name of the product or there will be HE after it.
- If the flue is made of plastic and steam is visible during operation
- There should also be a white plastic pipe coming from underneath the boiler leading to a drain.
This is important information for two main reasons
- If your boiler is undersized then it ill struggle to meet your home heating requirements
- If your boiler is oversized then you could be wasting money on two counts, energy bills, and the installation costs.
It is a good idea to take into consideration any future plans at this stage. Eg. extensions, extra bathrooms etc. as you want a boiler that will cope with the added demand
What size combi boiler do I need?
Pretty much every combi boiler on the market will be adequate on the heating side of things. The important thing with a combi boiler is the hot water performance. This is where a proper home survey needs to be carried out.
As a rough guide to combi boiler sizing;
- A very rough guide for combi boiler sizing.
- Smaller properties such as apartments or small houses. With up to 10 radiators will require a 24-27kw combi.
- Medium to large properties with 3-4 bedrooms an *ensuite shower room. And the main bathroom with 10-15 radiators will require a 28-34kw combi.
- Large properties with up to 20 radiators and *two bathrooms a 35-42kw combi would be required.
* a combi will struggle to run two showers at the same time. In this instance a system boiler. With un-vented hot water storage would be worth considering.
What size system or regular boiler do I need?
When sizing a system boiler or regular boiler the main thing to consider is the number of radiators on the system.
As a rule of thumb, we allow 1.5kW per radiator.
So if you have 15 radiators 1.5 x 15 = 22.5 kW
This is just a rough guide and some times its better to do a whole house heat loss calculation. This allows us to work out how many KW each room will need.
What is a magnetic filter?
A magnetic filter, when installed on the return pipework to the boiler. Has the job of catching any suspended debris in the system water. Before it is drawn into the boiler and recirculated around the radiators.
Last year the British standard was updated and now stipulates that every new boiler should have a system filter installed. Some manufactures won’t offer extended guarantees without a filter.
Why do I need a flush?
Heating systems are made up of steel radiators and copper or plastic pipework. The steel radiators filled with water are prone to corrosion. A poorly designed system or lack of protection can lead to a badly sludged system.
The sludge is made up of metal particles, Magnetite. The sludge accumulates in the radiators and limits heat output and circulation. The sludge will also collect in the Boiler or heating pump and can lead to failure. If you think your heating system is suffering from a sludge build-up. See our article on Magnacleanse power flushing.
The telltale signs your heating system is in poor condition are
- Cold spots in your radiators, especially along the bottom
- Noisy radiators and boiler
- Some radiators take longer to heat up
- House takes longer to warm up
- When you bleed your radiators the water is black
If this is the case then your system would benefit from a flush.
Timers and programmers
Timers and programmers have three settings
- Boiler turns on and off at set times
Timers and programmers give you the ability to set certain time periods for the boiler to be on. A timer like this won’t regulate the temperature, so for that you need a room thermostat.
A room thermostat measures the air temperature and tells the boiler when it is warm enough, switching the boiler off. In the same way, if the room drops below the desired temperature. The boiler is then fired up again to maintain the level of comfort.
Programmable room thermostat
A programmable room thermostat is a combination of a timer and a stat all in one. This allows you to set the time periods and the temperature from the same device
A smart thermostat is an internet-connected device. That allows you to remotely control your heating system from elsewhere. Eg. on your way home from work. They also connect to any smart home systems you may have eg. Amazon Echo, Google Home and Apple HomeKit.