New Combi Boiler Installation In North London

Boiler Installation & Advice

If you are looking for a New Combi Boiler installation before the winter, we at MML Plumbing can help you choose the right Combi Boiler that fits perfectly in your home.


If your old boiler is not performing as it used to, this will be a guide about what to look out for before a Combi Boiler installation.


We will cover:

  • All you need to know about a Combi Boiler
  • 5 big advantages of a Combi Boiler
  • The right size boiler to your property
  • The installation cost of a new Combi Boiler
  • Make your decision
  • The Most Important thing YOU have to do next

All you need to know about a Combi Boiler

So what is a Combi Boiler or Combination Boiler?


A Combi Boiler only heats when there is a demand. This means you won’t be storing and heating water in a water tank and wasting money heating up the water even when you’re not using it.


A Combi Boiler will give you hot water instantly, without the need for heating up a hot water cylinder.


A Combi Boiler will prioritise hot water. This means that if someone wants to use the shower when the heating is on, the boiler will focus the attention on the shower. After the demand for hot water has finished, the Combination Boiler will switch back to heating mode.


If you want to install a new Combination Boiler, the good news is that it is cheaper to install compared to a system boiler with a storage tank, and the labour will cost less too.


If you have an old system or regular boiler you still can upgrade for a new Combination Boiler! All we have to do is to remove the old hot water cylinder and change the pipework.


If you have more than 2 bathroom and people are using constantly, in this case, you need a system boiler. You can’t use a Combination Boiler with multiple bathrooms because the boiler can’t cope with the hot water demand.

5 big advantages of a Combi Boiler!

1. It is more efficient:

With a new Combi Boiler installation you can save up to £400 a year on your heating bills!


2. It is Cheaper:

Combi Boilers are not as complicated as traditional heating systems. This means that your new boiler installation cost will be lower compared to the installation of a system boiler. In the long run, it’s also easier to find parts for the boiler too.


3. A Combi Boiler will give you instant hot water:

No more waiting for hot water. A Combi Boiler doesn’t have to heat up a water tank, and because of this you can have an unlimited hot water supply. You also don’t have to worry about legionella bacteria in the water tank, which can grow if the water temperatures in your cylinder drops bellow 50 Celsius. In this case all you have to do is to heat up your water above 60 Celsius to kill all the legionella bacteria.


4. It is compact:

There is no more water tank, so with a new boiler installation or system upgrade you save a lot of space. A Combi Boiler can fit in a kitchen cupboard. It’s ideal for homes where there is limited space. You save a lot of space, because there is no more cold-water feed tank in the loft and no more hot water tank in the air in cupboard.


5. Higher water pressure:

After your new Combi Boiler installation you can enjoy a better shower with higher water pressure. The Combi Boiler is fed directly from the mains. Also you are less likely to have an airlock in the system.

The right size boiler for your property

Now that you know you have to install a new Combi Boiler, we have to determine what size will perform best in your home.


What we have to consider is the square footage of your property, how many bedrooms you have, the number of radiators you have, the hot water demand and of course how many people live in the house.


Before a new boiler installation, it is very important for us to find out all the answers for the questions above.


The chart bellow give you some ideas what size of Combination Boiler you need:

Property Type



Boiler Size

1-3 bedrooms 1 Up to 10 24kw-27kw
2-4 bedrooms 2 Up to 15 28kw-34kw
3-5 bedrooms 3 Up to 20 35kw-42kw

The installation cost of a New Combi Boiler

A new Combi Boiler installation can vary in cost. You can’t compare your neighbours installation to the cost of your installation. Every new boiler installation it’s different. The location of the boiler, running the pipe, pipe sizing, running a new gas pipe, vary for each installation.

No one job is the same. Contact us and we will give you a fixed prices. Estimate is free of charge.


When we come out for a free estimate, we will check even the smallest details, like a small 15mm gas pipe under the floorboard that may need to be increased by size at least to 22mm so the new Combi Boiler can function properly.


And at the end of the free estimate we can provide a fixed price for your new Combi Boiler installation.


In some cases we have to do a few additional jobs so the new boiler can work properly and be up to the gas safe regulation.

These works are:

  • An undersized gas pipe that needs to be re-running. If not, the old gas pipe can not supply enough gas to your boiler. Undersize gas pipe can cause the boiler flame go out when you turn on the cooker while the boiler is running. This can classify as immediate dangerous situation (ID)!
  • We have to repair the plasterboard, ceiling, and brickwork.
  • You have to relocate the boiler in different room or to the loft.
  • If you put the boiler in the loft this need to be sealed and frost protection need to be installed. 

Make your decision!

When it comes down to install a new Combi Boiler, there are varied opinions throughout which boiler to choose.


Most leading brands like Baxi, Vaillant, Worchester Bosch, Ideal, Potterton have good quality boilers. The most important thing and differences in the brands is the warranty that they offer, and the type of materials used to build the Combi Boiler.


At MML Plumbing we install only quality Combi Boilers. We give you advice about the best boiler for your home, thinking about the future, so you can get a long parts and labour warranty from the manufacturer. When we install a new Combi Boiler, we normally choose a boiler with a 5-7-10 year parts and labour warranty.

The Most Important thing YOU have to do next!

  • Find a gas safe registered company like MML Plumbing.
  • We can give you advice and estimate for any new boiler installation.
  • We give you peace of mind that your new boiler will comply with the new building regulations.
  • We self-certify the new boiler
  • We notify Gas Safety about the installation.
  • Gas Safety will notify to the Local Authority.
  • And a Building Regulation Compliance Certificate will be sent out to you within 2 weeks.


After you receive the Building Regulation Notification Number, you have to write this number to the benchmark commissioning checklist, that you will find on the back of the boiler installation manual. Our gas engineers will advise you where can you find the benchmark page.


If you still have more questions about a new Combi Boiler installation, don’t hesitate to reach out to us for a free estimate at 02083550840

or by e-mail [email protected]


We are based in Barnet, covering North London and 20 miles to north from our address 103 Ribblesdale avenue, n11 3aw.