Why should I have my boiler serviced each year?

For your boiler to work safely & economically, all boiler manufacturers recommend that the appliance is serviced each year by a competent person (GAS SAFE registered).

Gas Safety – Top 10 Tips

Gas Safety Tips from Thames Valley Boilercare

1. Always check that an engineer is Gas Safe registered.

It is against the law for anyone to do work on gas appliances in the United Kingdom, Isle of Man or Guernsey unless they are on the Gas Safe Register.  Always check that an engineer is Gas Safe registered before you let them work in your home on the Gas Safe Register website or by calling 0800 408 5500.

2. Registered gas engineers will have a Gas Safe ID card.

The Gas Safe ID card looks like this:

Gas Safety - Gas Safe Register ID card

There are different kinds of registration – for example, someone may be registered to work on your boiler or pipework, but they might not be qualified to install a gas fire. You can check what kind of work they are qualified to do on the back of their card.

3. It’s illegal for someone who works for a Gas Safe-registered business to do private work.

Hiring someone who normally works for a reputable firm, but is doing some extra work ‘on the side’ isn’t the good idea it might seem – it’s actually illegal.

4. Report anyone who you suspect of working on gas illegally.

If you think someone is working on gas illegally, report them to the Gas Safe Register and they will investigate their work.

5. Nominate your gas work for an inspection.

If you’ve had gas work done in the last six months, you can nominate it for a free gas safety inspection from Gas Safe to make sure it’s up to scratch.

6. If you move house, get your appliances tested.

If you move into a new home, don’t assume the appliances are safe – get everything checked by a Gas Safe registered engineer.

7. Know the symptoms of carbon monoxide poisoning.

Know the symptoms of carbon monoxide poisoning – it could save your life:

  • headaches
  • dizziness
  • nausea
  • breathlessness
  • collapse or loss of consciousness
  • symptoms which disappear or get better when you leave home and come back when you return
  • other people (and animals) experiencing the same symptoms at the same time

8. Know what to do if you suspect carbon monoxide poisoning.

Know what to do if you suspect carbon monoxide poisoning:

  • get fresh air immediately – open the doors and windows
  • turn off any gas appliances and turn the gas off at the meter
  • extinguish naked flames
  • leave the house
  • see your doctor immediately or go to hospital – let them know that you suspect carbon monoxide poisoning
  • call the Gas Emergency Helpline on 0800 111 999 if you think there’s any danger

9. Check for warning signs that your appliances may not be working properly.

Check for warning signs that your appliances may not be working properly:

  • the flame on your gas cooker should be crisp and blue. Lazy yellow or orange flames mean you need to get your cooker checked
  • you may see soot or black marks or staining around or on gas appliances
  • your pilot lights may go out frequently
  • you may see increased condensation inside your windows

10. Get an audible carbon monoxide alarm.

Get an audible carbon monoxide alarm. You can’t taste, smell or see carbon monoxide, so an alarm is a good way to protect yourself.  Carbon monoxide alarms look like a smoke alarm and are easy to install and should cost under £20.  Make sure the alarm you buy has a British or European approval mark on it, such as a Kitemark.

Boiler Types

Whatever type of boiler you’re thinking of buying or if you just want to find out more about the one you have, our boiler guide will help.

There are three main Boiler Types: combi, system and conventional. buy cialis tablets. Combi boilers

Combination boilers – more commonly known as combi boilers – are the most popular kind in the UK and provide heat and hot water with no need for water tanks or cylinders.


  • you get unlimited heat and hot water when you need it.
  • there’s no need for a tank in your loft.
  • they don’t take up much space.


The water pressure might be reduced if you need hot water from more than one tap at a time.

Suitable for

Almost any home, but best for homes where lots of people won’t need lots of hot water at the same time.


System boilers

System boilers – also known as sealed system – come with a water cylinder (which usually sits in an airing cupboard) and no water tank.


  • there’s no need for a tank in your loft.
  • you can get hot water from multiple taps at the same time.


  • you don’t get hot water instantly.
  • the hot water can run out and you’ll have to wait for it to reheat.
  • you need to find room for the cylinder somewhere.


Suitable for

Homes which need to have hot water in more than one place at the same time.


Conventional boilers

Conventional boilers – also known as open vent or regular boilers – have both a cylinder and a tank.


You can get hot water from multiple taps at the same time.


  • the hot water can run out and you’ll have to wait for it to reheat.
  • you need to find room for the cylinder and the tank.


Suitable for

Homes which need to have hot water in more than one place at the same time.

Condensing boilers

Condensing boilers aren’t strictly a boiler type – instead it’s an attribute your boiler can have, e.g. you can have a condensing combi boiler or a condensing conventional boiler.

Condensing boilers are very energy efficient because they capture some of the heat which would escape from the flue of a non-condensing boiler and re-use it.  This means they get more heat from the same amount of fuel, which will save you money on your heating bills.

All new gas boilers have had to be condensing since 2005 (although in exceptional circumstances non-condensing boilers are allowed).

Energy-efficient boilers

All new boilers are energy-efficient – since 2010 all new boilers must be A-rated for energy efficiency, or at least 88% efficient.

The energy efficiency rating system for boilers is called SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK).  All boilers are assessed and given a rating to help you pick a boiler that is energy-efficient, or see how efficient your existing boiler is.

What’s the real cost of a new boiler?

How long will it take to make back the cost of a new boiler in savings

A new boiler is not cheap. The cost of a new boiler can be anywhere upwards of £1800 when you include installation, so it’s important to get all the facts before you make a decision. Here we look at whether or not it’s worth replacing your old boiler and how long it will take for the investment to pay for itself.If you decide to install a new boiler in place of an old energy-inefficient one you can expect to save some money on your gas bills.

If you opted for a new boiler with 90% efficiency costing £1800, here’s how much you could expect to save on a typical gas bill and how long it would take to pay for itself:


Efficiency of your old boiler

Annual saving on your gas bill in %

Annual saving on your gas bill in £

How long it will take for your boiler to pay for itself




7.6 years




9 years




11.4 years




14.8 years




22.8 years

Calculations based on a home with gas-powered central heating, using an average 17252 kWh gas p/a at a cost of £666 p/a.

A new boiler could also add to the value of your home, so take this into consideration when you’re adding up the costs.

When to get a new boiler

  • If your boiler is beyond the point where it’s cost-efficient to repair it. If you’ve called out a qualified engineer to look at your boiler and they’ve told you that it’s at the point of no return then it’s time to make the investment in a new one.
  • If your boiler doesn’t give you the control over your heating that you need – for example if the controls or timer aren’t very flexible, or there isn’t a thermostat – a new boiler might be a good option when it comes to helping to cut your heating bills. In some circumstance, you might be able to get away with just installing new controls.
  • If your system has a ‘dry cycle’. A dry cycle is a feature found on older boilers which means that if the heating is on, but your home is already at the temperature set by the thermostat, it won’t switch off, but instead will send the heat to an ‘overflow radiator’ (usually in the bathroom). This can be a real energy waster, because you’re heating your home when you don’t need to be.
  • If your boiler has a continuous pilot light. (This is the flame you can see burning through a small window on the front of some boilers.) This is a common feature on older boilers and it’s a real waste of gas.
  • If your boiler is on the floor rather than on the wall, it is likely to be older and much less energy-efficient.
  • If your boiler is G-rated for energy efficiency it’s a good idea to replace it. You can find out the energy efficiency rating of your boiler at .
  • If you want to sell your house or you’re renovating your home a new boiler could add to its value.


Things to do before you buy a new boiler

  • Have your boiler serviced. A service will make sure that it’s running properly and can eliminate lots of problems. Read our boiler maintenance tips for some simple measures you can take yourself to help your boiler run better.

A new boiler is a big investment, so it can take a while to make your money back in savings. Here are a few cheaper measures that you could take to cut your heating bill:

Central Heating Systems

Thinking about new central heating systems, or just want more information on the one you have? Read this guide. Your central heating system plays an important role in your home – keeping you supplied with the heat and hot water that make life so much more comfortable. But what systems are available and how do they work?


What types of central heating systems are available?

Central heating is a way of providing warmth in your home from, as the name suggests, one central source. Central heating systems broadly fall into one of the following types:

  • ‘wet systems’ involving a boiler/heat exchanger and radiators
  • warm air system
  • storage heaters



How does a wet central heating system work?

With a ‘wet system’ hot water circulates through a system of pipes that connect to the radiators throughout a house. At the centre of the system, a boiler burns a fuel – or sometimes there is a ‘heat exchanger’ and this heats the water that feeds the network of pipes. ‘Wet systems’ are the most popular form of heating system in the UK.

Radiators, despite their name, do not just give off radiant heat, in fact they deliver most of their heat through convection; air warmed by the radiator naturally rises, and cool air falls relative to it, as a result the warmed air circulates and the ‘space’ in a room is warmed.

The pipework may also be connected to a hot water cylinder (tank), which will provide a supply of hot water for bathing and washing.



What type of fuel is used in a boiler?

The most common fuel used in boilers is natural gas, followed by heating oil, and occasionally liquid petroleum gas ( LPG ). Although rare, some boilers burn coal (usually in the form of coal pellets) or biomass (usually in the form of wood chips). Electric boilers are also available.

New gas (and oil) boilers have to be of around 90% efficiency or higher (an A or B energy efficiency rating) and generally use condensing technology to achieve this. If your boiler is more than fifteen years old, you may want to consider replacing it with a new energy-efficient one.



What is the difference between a combi boiler and a conventional boiler?

As well as taking care of your heating needs, combi boilers provide instant hot water. They have the advantage of freeing up space in a home, because there’s no need for a hot water cylinder (tank) like there is with a conventional boiler.

In most cases, heating water instantly is more energy-efficient than ‘stored’ hot water systems. However, the flow of hot water is slower than if it was coming from a cylinder, so a bath will take longer to run. Some combi boilers can in any case also heat water in a cylinder.

Modern boilers generally no longer have tanks in the loft to ‘pressurise’ the system through gravity. Instead they are sealed systems, and typically only require manual topping up from the mains water supply when the internal pressure has dropped (usually because of tiny leaks). This is a simple operation that takes a few seconds, and involves opening a valve on a pipe below the boiler.



My home is heated via a district heating system, how does this work?

In some areas, notably Nottingham, a centralised district heating source will deliver hot water via a series of underground pipes to a number of homes simultaneously, removing the need for a domestic boiler. This mains hot water then circulates around the pipes within the home to provide heating and hot water. The attraction of this type of system is its energy efficiency and low carbon footprint, and for the consumer it means lower energy bills.



I’ve heard that ground source heat pumps are environmentally friendly, but will they lower my energy bills?

A ground source heat pump works on the same principle that fridges and air conditioning systems work on – making one place cooler while making another place warmer – or the other way around. If you consider how warm the back of a fridge gets, while the inside of it gets cold, then you begin to get an idea of how this system works.

Ground source heat pumps, fuelled by electricity, work by making the earth outside a home colder, by running a refrigerant fluid through pipes that are buried in a trench or a borehole, while delivering warmth at the heat exchanger indoors. That heat is transferred to the water running through the pipes inside a house to warm radiators and provide hot water.

Ground source heat pumps typically reach temperatures of around 50°C, which is significantly lower than with a boiler, which can reach a temperature as high 90°C (although it’s recommended that you set the temperature lower than this). So, you will need to run a heat pump for longer to achieve the same level of comfort, and it tends to work better with underfloor heating, rather than radiators. Although much more expensive to install, they can be as cheap to run as gas central heating. they are a good option to consider if you live off the gas network.



How does a warm air system work?

Warm air systems were sometimes installed in the sixties and seventies in the UK, but continue to be popular in North America. Air is heated by a boiler, typically fuelled with natural gas, and fed via ducts to rooms around the home. The warm air enters the room via a floor or wall vent.

In commercial buildings, variations on warm air systems are still in widespread use, although they typically also serve as a cooling (air conditioning) system.

In most homes, warm air systems have been replaced with ‘wet’ systems, which are generally more comfortable and efficient.


How does a storage heating system work?

The principle of a storage heater is that it contains bricks capable of storing large amounts of heat. These are heated overnight using the off-peak electricity on Economy 7 and, on Economy 10 tariffs, during two shorter periods during the day. This heat is then gradually released the following day.

Storage heating systems, although consisting primarily of individual storage heaters, typically rely on a separate wiring system within the home for cheaper off-peak (Economy 7 or Economy 10) electricity, so can still to some extent be described as a ‘centralised’ system. The same wiring typically will also be used to heat a hot water cistern (tank).

A storage heater normally has at least two controls, one for controlling how much electricity is used, which will determine how much heat is generated for storage, and another for controlling how much heat is released. This means that if you’re out during the day, you can delay the release of the heat until you return in the evening. More advanced storage heaters also have thermostatic controls.

Unlike older storage heaters, which took up a lot of space, modern ones use bricks with much greater heat storage capability, and are far more streamlined.

In some cases, storage heaters can also serve as direct electric heaters, providing heat directly from electricity without going through the storage stage. Typically they will use peak rate electricity for this. Often homes that rely on storage heaters will also have separate electric heaters to supplement heating needs; again peak rate electricity will be used to top up in this way.