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Buying a New Boiler: What to Consider?

A boiler is the heart of a home’s central heating system and supplies heat to all the radiators and hot water to the taps. It works by burning gas to heat water before feeding it to the central heating system.

There are many factors and options to consider when choosing which boiler is best suited to your requirements and your home. The type of property and usage are the key factors, but you will also need to consider the site of the boiler and your budget. The last thing you want is a boiler that doesn’t suit your home.

What kinds of boilers are available?

Boilers come in all shapes and sizes, but which one is right for you?

Combi boilers:

  • Most likely to suit all households.
  • Ability to control both your central heating and hot water just from one unit.
  • Compact size, making it a good option for smaller properties.
  • No loft space needed in your home.
  • Installation can end up cheaper because there is less pipework involved.
  • Provides a constant flow of hot water from the mains.

System boilers:

  • Most suited to homes with more than one bathroom.
  • Doesn’t need a loft tank, which saves space.
  • No feed or expansion cistern makes them more efficient.
  • Offer a constant supply of hot water to any number of taps.

Conventional boilers:

  • Perfect for homes where a lot of hot water is used at the same time.
  • Suitable for large households with two or more bathrooms.
  • Requires a cold water storage tank in the loft as well as a hot water tank.

The most common boiler sizes:

24-25kw – suitable for flats and houses with 2-3 bedrooms, with up to 10 radiators.
28-30kw – suitable for 3-4 bedroom properties with up to 15 radiators.
33-35kw – suitable for large houses with up to 20 radiators.
40kw+ – suitable for larger properties with more than 20 radiators.

If you live in a small home with only one bathroom, or live on your own or with only one other person, a standard combi boiler without a hot water tank will usually be the best choice.

How long boiler does installation take?

In general, boiler installation may only take a day, assuming your chosen model is available. If it’s not an emergency boiler replacement, then try to replace your boiler before it gets too cold as there will be more availability.

When should I consider buying a new boiler?

Unless you’re upgrading your boiler before a problem occurs, it’s likely you’ll be replacing an existing one because it’s not functioning correctly.

However, if you’re experiencing technical issues with your boiler, speak to one of our engineers who will be able to check it for you and see if it can be repaired. If this is not the case our engineers will be able to recommend the best type of boiler to replace it with, taking into consideration the size of your home and budget. Call us on 0114 272 2586.


Which Size of Boiler Should I Choose?

Fitting the right boiler for your home is extremely important, you need to find a boiler that is just right for your home. A boiler that is too small will not be able to heat your home adequately or produce enough hot water. A boiler that is too big will produce more heat than needed which will increase bills, waste energy and produce unnecessary emissions.

Neither is a great way to live, so how do you find the solution?

How to calculate the right size boiler for your home.

The size of a boiler, also known as output, is measured in kW. This means, the higher the number the better the supply of hot water, but this doesn’t mean you should be buying the highest output available. Generally, boilers range from 24kW to 42kW in size.

There are a few things to consider when choosing the right size boiler for your home:

Current boiler size

It’s a good idea to know the size of your current boiler but don’t assume you need to stick with the same size going forward. Several things may have changed since it was installed such as the household’s water demands, the level of insulation or the addition of an extra bathroom. Or you may have plans for the near future such as loft conversion or an extension.

If your home is regularly running out of hot water, it could mean that your current size of boiler is not up to the task and you need to think bigger. However, if your boiler is more than 8 years old, it may just be a case of inefficiency rather than a lack of capacity.

Size of your home

Usually the more radiators and bathrooms you have the higher the output of your boiler will be. You should also be aware of the size of the area that you are trying to heat. It is worth taking into consideration that an electric shower doesn’t reply on a boiler for hot water so doesn’t need to be included in any calculations.

For example, if you were interested in having a Combi boiler fitted, here is a rough sizing guide:
24-27kW – small house (1-2 bedroom) or flat, up to 10 radiators, 1 bathroom
28-34kW – medium house (3-4 bedroom), up to 15 radiators, 1-2 bathrooms
35-42kW – large house (4 or more bedrooms), up to 20 radiators, 2 or more bathrooms

Hot water demand

Most replacement boilers that are fitted are Combi boilers, which heat water on demand so there’s no waiting around for the water to heat up. However, this does mean that you need to give some thought as to how much hot water your household gets through on average per day. If you have lots of showers, baths or sinks running at the same time then a Combi boiler may struggle to cope with the demand.

How else can I make my home as cosy as possible?


If your home isn’t insulted fully there could be a risk that you are losing a lot of heating through the roof, walls, floors or windows. To help give your heating system the best chance to do its job, you should think about investing in more efficient insulation techniques.

Smart Controls

Controlling your boiler has become easier than ever and it’s now possible to adjust the temperature of your home from any location via smartphones or tablets allowing you to reduce the amount of energy you waste. Some can even automatically compensate for the weather outside.

Annual boiler servicing

To make sure your boiler is running at its best for as long as possible, it’s important to get it serviced by a professional on an annual basis. This allows for problems to be caught early before they develop into long term damage.

Speak to a professional

Our friendly and fully qualified engineers will be able to advise you on the right size boiler to suit your lifestyle and your household.
Contact us today on 0114 272 2586.

Guide to Bleeding Radiators

You may have had the central heating on low once or twice over the summer but most people tend not to have the heating at full pelt until winter time. It’s more than likely that if there is a fault in your heating system you won’t notice it when the weather is warm because you aren’t using it as much. Even if you don’t need the heating on, it’s advised to fire it up once a month to prevent a buildup of sludge or corrosion and to make sure everything is still in working order.


If there’s a problem with your system, it’s best to give it a test now, at the end of summer before you start to rely on it. Here’s how to check that your radiators are working properly, and how to bleed your radiators if needed.

How to tell if your radiator needs bleeding. 

Put your central heating system on and turn on all the radiators. If the radiator has a cold patch towards the top or isn’t warming up at all, it’s a sign that it needs bleeding. The cold areas are happening because of trapped air in the radiator, which needs to come out in order for it to work effectively. Air enters your heating system whenever fresh water is added, so whenever you use water, air enters the radiator. If you use a lot of water, you may need to bleed your radiators more often.


Air rises, so it’s more likely that the radiators upstairs will need bleeding. But if you have a radiator that’s cold on the bottom floor, it’s best to bleed all your radiators.

How to bleed your radiator.

  1. Switch your central heating system off. You don’t want to burn yourself, water will come out the radiator so it absolutely has to be cool for your own safety.  More air may be sucked in if the system is still on.
  2. Get a towel, a radiator key and a container to catch the water. If you aren’t sure what a radiator key is, they look like this;
If you can’t find one in your house, you can buy them from hardware shops or you could perhaps borrow one from a neighbour.


  1. Find the bleed screw on the radiator, it’ll be on the side of the radiator at the top. It looks like this.

  1. Put your container under the bleed screw to catch any water that comes out.
  2. Use the radiator key to turn the bleed screw anti clockwise. You should hear a hissing sound as the air comes out. Use the cloth to stop any water spraying out.
  3. Wait till the hissing air sound stops and water starts trickling out instead.
  4. Reseal the bleed screw with your radiator key turning it clockwise.
  5. If you’re doing all the radiators in the house, start downstairs beginning with the radiator that’s the furthest away from the boiler. Then do the upstairs ones, again starting with the one farthest from the boiler.
  6. Switch the heating back on, check that the area around the bleed screw is not leaking. Make sure that there are no more cold areas and the radiators are working properly.
  7. Bleeding your radiators can lower your boiler pressure, so check that the pressure gauge on your boiler is normal. Here’s what to do if your boiler is losing pressure.
If your system still isn’t working properly:
We can help. 1st Call Gas are on hand to service, repair or do maintenance on your boiler and central heating system. Our maintenance monthly packages start from just £7 a month. Call 0114 272 2586 for more information.

Why You Should Consider Underfloor Heating

Underfloor heating is a great way to keep your home warm. It is a highly effective and efficient method of heating your home, whether it be a new build, renovation or single area. It allows you to create a minimalist look, making more space for paintings, shelf units or even picture windows.
If you’re considering investing in any underfloor heating system, one of our friendly and experienced fitters at 1st Call Gas who will be able to give you a quote and explain the best way to get started.

Why should I consider underfloor heating?

It’s much more aesthetically pleasing.

A room with underfloor heating means no radiators, which gives you an opportunity to really experiment with interior design and the layout of your room. Ever been trying to arrange your room and not been able to put your sofa or bed where you wanted it because the radiator is in the way? If you’re working with a small space like a terraced house, underfloor heating can solve a lot of issues.

Underfloor heating can be installed below stone, tile, wood or carpeted floors (as long as the carpet isn’t too thick – a 1.5 tog is generally considered a maximum suitable thickness). So the world is your oyster when it comes to design. It can also enhance your homes selling price. Underfloor heating has a reputation for being state of the art and high spec, it could attract buyers looking for a luxurious property.

It’s energy efficient.

A suitably sized unit can heat a larger area than an individual radiator. It also works at a lower temperature, so it could reduce your heating bills. If you have open windows or a draughty room, the floor will still stay warm, underfloor heating evenly distributes heat around the room. So while you have the initial cost of installation, in the long run it could pay for itself.

It’s amazingly cosy.

A room with underfloor heating is so much more comfortable. The whole room is evenly warm, there are no hot/cold patches of the room like there can be with radiators. The floor being warm and cosy means that you can walk around barefoot all year round (you won’t want to wear slippers anymore). This is particularly welcoming in the bathroom when you step out of your bath or shower. Imagine sleeping in a bedroom which has the heat coming from under your bed instead of the opposite end of the room – very nice!

If you do have a stone, tiled or wooden floor then underfloor heating will take the chilliness of the hard surface away and make it much more pleasant.

What is involved with underfloor heating?

The cost of installing the underfloor heating system will depend on many factors, including whether you choose an electric or water-based system, the number of rooms you want to heat, whether you’re fitting a new-build, extension or an older building and what kind of flooring you have.

  • Electric systems – Electric underfloor heating involves a series of electric wires installed under or within the floor, which is quite a simple process and doesn’t add much thickness to the floor. This means it can be easily installed into existing bathrooms, bedrooms or kitchens. Because the system is electric, it is not linked to your boiler and will affect your electricity bills not your gas bills.
  • Water-based systems – A water based underfloor heating system has a series of water pipes running under the floor which are connected to your boiler. This system is ideally suited to be installed during a new build construction because it does add thickness to the floor. The price of installing a ‘wet’ system can vary, depending on factors like whether the room you’re heating is on the ground floor, or how close it is to the boiler.

When you invest in a new underfloor heating system, it’s ideal to make sure you also have good insulation in your house so that you know your heat is not being wasted.

We’re fully qualified to advise you on which underfloor heating system to get and what the possibilities are. You may wish to heat a certain area of a room or your whole house! If you’d like to find out more about this particular service then please call us on 0114 272 2586

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