What are the pros and cons of a combi boiler?

This is a question I get asked a lot when helping customers choose the right boiler for their property.
Hopefully this article will help to make the facts a bit clearer so you can understand the pros and cons of a combi boiler installation before making a decision.
Many people I go and see will say to me right from the off ‘I would like a combi boiler please’ without really understanding the negative aspects of a combi verses other choices that may be available.

Combi Boiler Pros ✔

☻      A Combi boiler in most cases removes the requirement for a cold water storage tank in the loft. This is because the previously stored cold water services from the tank are converted onto the mains supply dramatically increasing the pressure to taps and showers in the house.

☻      Removing the water tank also frees up space in the loft for storage or a conversion leaving you with whats called a dry loft. No water services in the loft reduces the risk of water tanks or pipework leaking through the ceiling in future so provides peace of mind!

☻  As part of a combi boiler conversion the hot water cylinder is also usually removed, freeing up a handy storage space.

☻ A combi boiler provides hot water on demand, in other words when the hot tap is turned on the boiler will fire and send hot water to the tap. In theory you should only be paying for the hot water you use and need. With a traditional hot water system the boiler heats the cylinder and the stored water sits there until it is drawn off, so there is always the risk of water being heated unnecessarily, if not exhausted before it cools down.

☻ A combi boiler also increases the hot water pressure to all taps and showers, which once combined with the increased cold water pressure is a big perk of removing your tank fed system. Showers will automatically become power showers, compared to a standard non pumped traditional system and taps miraculously come to life!

☻ Due to the cold water main now being the primary source to all taps, you can now drink it! Very handy in the night should you wish to grab a drink of water and your bathroom is closer to your bedroom than the kitchen.


Combi Boiler Cons ✘

☹   Combi Boilers can only provide a limited volume of hot water to taps and showers, therefore unsuitable for properties with more than two bathrooms. If a combi boiler for instance, can deliver 18 litres per minute, which is about the maximum performance achievable right now, the 18 litres per minute has to be shared between what ever is being drawn off it. For example, with this boiler you could run two showers, each one achieving 9 litres per minute flow rate. If you were for instance running a bath, all of the performance (18 litres per minute) would be required to run that bath in a sensible amount of time. 

☹ Combi boilers and mains water systems in general are totally reliant on the pressure and flow rate to the house. It needs to be adequate enough to cope with all the cold water and hot water running from the same supply. The classic mistake we see, many plumbers do not check this first and install combination boilers in houses which should never have had the cold water storage tank removed in the first place due to low mains water flow rate. So, if you have 12 litres per minute coming into your property and your combi boiler is sized to heat 12 litres per minute, as soon as someone else turns on another tap in the house or a washing machine, it will starve the combi boiler of water. If this happens and you are in the shower, it will just trickle out for a while or stop completely until full pressure is restored to the shower. 

Here is the simple test we do on a site survey to check you have adequate flow rate to your house. 

☹ Combi boilers do not have a back up, so in the event that the boiler breaks, in most cases you will lose both heating and hot water until the boiler is repaired.

Bringing your hot water and heating into one nice neat box does have its downsides. Some clients negate this by also Installing an electric shower which does not need the boiler to provide hot water and will work independently. 

☹ Hot water will take a long time to reach taps or showers when hot water draw offs are a considerable distance away from the combi boiler.

This can be  frustrating and wastes water on a grand scale! TIP-Look at the proposed location for the combi boiler and then the furthest tap away from the boiler location. If for example you are thinking of Installing combi boiler on on the ground floor of a town house and there is  a bathroom on the 2nd floor you will experience this problem and worth avoiding . This is the reason why hot water cylinders are usually sited in the central of  property to distribute hot water quickly to the taps.

☹ Combi boilers are much more prone to scaling up as the plate heat exchanger fitted to this type of boiler have very narrow water ways. This can be addressed by fitting  water softeners and magnetic system filters on the heating side. A clean combi boiler is a happy boiler!

☹ Modern combi boilers do not have as long a life span as a traditional system and they can become inefficient to repair near the end of their life. The best advice is to get the longest manufacturers warranty you can at the outset and keep the boiler regularly maintained with an annual boiler service. A good quality combination boiler depending on the amount of use should last 10 to 12 years.

I hope this article has been informative and although this post was not meant as an advert we would of course welcome anybody who is thinking of upgrading their boiler to contact us via the contact page or give us a call on 0800 2851920.

The purpose of this article is to educate and provide honest advice based on the facts and 25 years in the business. If you feel it has done that please LIKE AND SHARE the article from our Facebook page.

Thank you, Dean 



Commercial Boiler Installation Greenhithe

We were approached at the end of last year by Belmont Healthcare who own and manage residential care homes throughout the south of England.

They are very good at looking after patients suffering from dementia or other brain related illnesses and specialize in turning around failing care homes.

Our first project with them was to design and install a new boiler system to replace the aging Keston boilers which had past their sell by date on Greenhithe site.

They also had many other issues related to radiators not heating fully and not having proper control of the heating zones.

We removed this mess and replaced with two Vaillant ecoTEC boilers mated to Vaillant’s plate heat exchanger. This provides separation from the aging heating system and avoids any debris in the radiators entering the boilers and causing reliability issues.

We then used Vaillant VRC 700 along side VR70 and VR71 control modules which wire into all the existing heating and hot water zones to provide total control and automation of all zones.

The weather compensation cleverly detects when the outside temperature is warmer and the controller reduces the flow temperature of the boilers according, saving hundreds of pounds every year on gas!

This is a very basic Vaillant boiler commercial setup, however it was just what the client was looking for in this instance as cost of installation was also a big factor in us winning the job.

We are now surveying two other care homes on the south coast for Belmont Healthcare and looking for smart ways we can save the client big money on fuel bills on those sites as well!



This is what we do in a nut shell, look for cunning ways to save energy and in turn save you money!

If you have any sort of installation where you feel you are paying over the top on your fuel bills I’m sure there is a way we can assist, please give us a call today.


Combination Boiler With 13 Year Warranty!

For the first time ever a boiler manufacturer is offering an incredible 13 year warranty

Alpha boilers have very generously increased the warranty on the E-Tec range from 10 to 13 years.

What’s the catch?

There isn’t one really.

The only stipulations are that:

  • The boiler is fitted with Alpha’s premier filter kit. (which protects the boiler from debris ingress)
  • The boiler is serviced every year. (by a qualified gas safe operative who is trained to work on Alpha boilers)

If you are replacing your aging combination boiler like for like you should budget between £2000 and £2500 for a direct upgrade.

This would include flue, upgraded controller and flushing the radiators.

Register your interest through our contact form or call us on 0800 2851920

Is The Nest IQ Camera For Me?

The answer really depends on possible siting opportunities.

The Nest IQ camera works best if it’s mounted facing people walking towards your property. 

The facial recognition function learns quicker if the camera can zoom onto faces front on.

Once it has recognized certain family members you can turn off the notifications and only have unfamiliar faces sending you alerts.









The key thing about the installation?

Having the power supply in close proximity to where the camera is ideally positioned.

When pricing to install Nest IQ cameras I do often find a socket close by.

However, getting the cable neat without the use of something to disguise it is more challenging.

We are Nest Pro installers at Cloverleaf.

If you are in any doubt about whether any of the Nest products are for you please don’t hesitate to call us!

All our advice is free and impartial!

If we do not feel you’ll receive value for money and get the full benefit of the Nest product you are thinking about we will be honest and tell you.

We pride ourselves on giving the right advice.

Use our contact form here for help.


Commercial Boiler Servicing Orpington

We have recently been charged with the responsibility of looking after the commercial boilers at Kevington Hall in Orpington.

This year we have carried out the appropriate servicing to nurse them through the winter months as the cold weather is nearly upon us.

We do not want to disrupt the occupants as the cold weather arrives so holding back on overhauling the plant room and boilers until Spring 2019.

We are working with the client to give Kevington Hall the most efficient system boiler system and controls out there.

The plant room will look very different once we have done our refurbishment work. Watch this space.


For all commercial boilers, upgrades or servicing inquiries, please call us now or send us through a call back request via the contact page.

We have successfully designed and installed commercial boilers in schools, churches and business premises around Orpington and other places in the London and Kent area.


Boiler Plus Legislation: New standards for domestic boiler installations

From 6th April 2018 the legislation around heating manufacture and installation in the UK is changing, and there are some big changes.

These changes have been named Boiler Plus and are being introduced by the Department for Business, Energy and Industrial Strategy (BEIS). They address the energy efficiency of heating systems and have raised the bar for both manufacturers and installers.

  • Gas boiler performance: space heating efficiency of the new boiler no less than ErP 92%
  • Time and temperature control required for all gas and oil boiler installations
  • Combi boiler installations must also include one of the following: Weather compensation, Load compensation, Flue Gas Heat Recovery, Smart controls.


The most notable change applies to the minimum performance standard for domestic gas boilers in England. The minimum efficiency level of all boilers manufactured and installed will be set ar 92% ErP. The main motivation behind the change is to phase out inefficient boilers and reduce carbon emissions in line with targets set by the EU. It forms just part of a wider plan known as the Government’s Clean Growth Strategy which aims to combat climate change and provide UK homes with greater comfort and lower energy bills.

What will happen to homeowners and installers who do not comply?

Installers who fail to install boilers in line with these new Building Regulations will be breaking the law and could be prosecuted by Building Control. The Gas Safe Register can also refer safety concerns to the HSE (Health and Safety Executive). Invoicing a customer for work which they claim to be legal but is not is also to be considered fraudulent under Trading Standards.

Homeowners who knowingly allow non-compliant work to be carried out could also face prosecution and fines of up to £5,000.

What is FGHR? A Flue Gas Heat Recovery (FGHR) is a device designed to improve energy efficiency of the boiler by recycling the heat from the flue gases which would usually be lost into the atmosphere. Instead this heat is used it to preheat domestic hot water.

What is weather compensation? Weather compensation devices enable the boiler to read the outside temperature via a sensor so that the boiler can adjust the temperature of your heating accordingly.

What is load compensation? Load compensation measures the response of the heating system and adjusts the flow temperature based on what is needed to reduce fuel consumption.

Why are these changes being introduced?

This legislation is designed to help the UK meet the targets by 2020. More than £2.5 billion of Government funding was designated towards lowering carbon emissions for the period 2015 – 2021.

Greg Clark, Business and Energy Secretary, said:

“This Government has put clean growth at the heart of its Industrial Strategy to increase productivity, boost people’s earning power and ensure Britain continues to lead the world in efforts to tackle climate change.

“For the first time in a generation, the British government is leading the way on taking decisions on new nuclear, rolling out smart meters and investing in low carbon innovation. The world is moving from being powered by polluting fossil fuels to clean energy. It’s as big a change as the move from the age of steam to the age of oil and Britain is showing the way.”

Some of the measures taken include:

  • Investment of around £3.6 billion to upgrade around a million homes through the Energy Company Obligation (ECO) including extended support for home energy efficiency improvements from 2022 to 2028
  • Upgrading all fuel poor homes to Energy Performance Certificate Band C by 2030 with as many homes as possible to be Energy Performance Certificate Band C by 2035
  • Improve the energy performance standards of privately rented homes to Energy Performance Band C by 2030.


Mega Flow Installation Grove Park

We thought we would share this new Mega flow Installation with you in Grove Park.

One of the builders we work for, namely Rixon & Rixon, converted a three bedroom house into a 6 bedroom property along Grove Park Road.

With the amount of bathrooms Installed it required a hot water solution to cope with high hot water demand and decent flow rate to all taps.

When high flow rate is a priority we will always recommend Heat Rae Sadia Mega flow.

In eyes our this is the industry leader in terms of performance and quality.










If you are struggling for hot water pressure in your property please call us and we’ll be happy to offer free advice and planning to suit your family’s requirements.



Shower Refurbishment with Urinal and Basin in Dartford

We recently completed a Shower refurbishment with urinal and basin in Dartford. We are very pleased to say the customers are very happy with the end result and will definitely recommended us to friends.




















Call us on 01322 227001 for more information.


Bathroom Refurbishment Bexley

We recently completed a full bathroom refurbishment in Bexley.

We are very pleased to say the customers are very happy with the end result  and have already recommended us to friends.

BEFORE- Bathroom refurbishment Bexley

The knock through













We are regularly asked the question, do we keep the separate toilet and bathroom or knock into one room?

Each to their own is the answer and completely dependent on your family set up and whether the dimensions of the room will allow you to maximise the extra space generated by knocking the partition down.

Knocking it though as we did on this job does open the whole room up to the possibility of bath and separate shower enclosure, which is lovely to have.

The only compromise is waiting for someone to get out of the shower when you need a pee!

This is not the first time we’ve carried out a bathroom refurbishment in Bexley village where we knock the toilet into one room.

We have also done it many times in Bromley, Sidcup and Dartford.

Vario Pro under floor heating












Personally i think this job is a great example of how you can do the knock through, fit separate bath and shower in without making the room look over crowded.

In this case the customer had plenty of input with tile choice and layout.

We just use your ideas and point you in the right direction to ensure your ideas will work on a practical level before diving in.

At the planning stage  we can give you as little or as much help as you require with bathroom design.

Either Jon or Steve, will take responsibility for the smooth running of your bathroom project along side our friendly Cloverleaf office staff.

Give us a try, you wont be disappointed.

AFTER – Bathroom Refurbishment Bexley.

800 X 800 mm Shower enclosure

Commercial Boiler Installation Surbiton

We were asked by Surbiton school for girls to design a new commercial boiler Installation for their science block.

This job wasn’t without its challenges!

The main one being, how on earth do you get a person in such a tight space to remove the  decrepit boiler in the first place?!

With a lot of blood sweat and tears that’s how.

Ben  managed to wedge him self into the plant room and break down the existing floor standing commercial boiler into sections.

and remove in manageable pieces.

We then used a Vaillant Ecotec 120KW in conjunction with a high performance plate heat exchanger and trusted Grundfos Magna pumps for circulation.

The plate heat exchanger prevents any debris from the aging radiator system entering the boiler circuit.

This is a configuration we use regularly for our church and school work and provides the client with reliability and longevity of the new boilers.

Upgrading to a  condensing boiler system along with up to date controls in a commercial premises

pays for its self very quickly!


The gas saving is nearly always 30 percent or more and the environmental impact from the exhaust emissions is also night and day from a 30 year old boiler to a modern condensing boiler.

Its not just about the way a boiler burns gas, new ERP boilers also save you money by only using the exact amount of gas required at any one time by carefully monitoring the demand.

The burner cycle  can also held off with up to date weather compensation controllers.

These stop the boiler coming on as much or at all if the weather outside is warmer than usual for the time of year.

I could ramble on about this all day, but in short if you are in charge of a commercial building and are looking to cut your gas consumption please call us.

I would be happy to carry out a free survey of your current commercial boiler Installation and provide you with a system design tailored to suit the type of building and your business needs.

Dean Dawe MD