How combi boiler is different from conventional boiler?


Table of Contents

Combi boilers, or combos, are in fact compact and solid machines. They fulfil the need for a central heating system and heat water whenever you need it. Undeniably, choosing the right boiler is critically important for better home heating and hot water needs. So, combos are a popular pick throughout the UK. They provide you with instant hot water despite the fact they don’t have a separate tank. Moreover, they’re ideal for small homes that don’t have more hot water needs. Next, you can replace the conventional boiler with combi cost through free boiler grants. 

On the other hand, conventional or regular boilers work differently. These contain a cold water tank usually located in the loft and a hot water cylinder (typically in the airing cupboard). Conventional boilers are a perfect choice for the needs of big families.

Did you get confused between combo and conventional? Well, to arrive at a good decision, you need to look at space, storage, efficiency, costs, performance, maintenance, and your home size.

Features of a Combi Boiler

These boilers keep your home warm and comfortable. They work as per their technological capacity and deliver good results. A combination boiler heats water straight from the mains as soon as you turn on a tap. It is a space-saver and ideal for small homes that don’t have enough space to house a water cylinder. Moreover, it maintains strong water pressure, particularly in key spots like the shower.  On top of that, this machine can be gas or electric, with natural gas or LPG being the most common. So do you want to replace conventional boiler with combi cost?

Conventional Boiler Features

A regular boiler, or conventional, contains a separate hot water cylinder as well as a cold water tank. Its cylinder boils up water for heating. What’s more, the boiler gets cold water from the tank on a daily basis. Also, its tank is high up, often in the attic. It tries to improve water pressure. Meanwhile, hot water storage occupies an airing cupboard.

For larger homes with higher hot water use, this boiler is the go-to. Just keep in mind the time it takes to reheat the cylinder.

Pros and cons of combi and conventional boilers

No doubt, most homes go for a combi boiler. But if you have multiple bathrooms, a conventional boiler might suit you better. This is because these boilers store hot water in a cylinder for higher demands. So if you don’t have one, consider this for newer homes.

Pros of CombiBoilers

  • High energy efficiency.
  • Space-saving for small homes.
  • Instant hot water.
  • Cost-effective heating, plus moving it is affordable.

Combi Boilers Cons

  • Limited hot water for big homes.
  • Needs strong mains water pressure.
  • Not for larger homes.

Pros of conventional boilers

  • Perfect for low-pressure spots. These boilers work well in areas with weak water pressure. They use gravity-fed water from loft tanks to create needed pressure.
  • Handles multiple outlets. When it comes to work, these machines deliver hot water to many bathrooms or outlets at a time. So they’re great for larger homes.
  • Goes green with solar panels. Solar thermal panels are compatible with these boilers. Together, they function for eco-friendly heating choices.

Conventional Boilers cons

  • Needs space. These take up lots of room due to requiring a hot water cylinder and a cold water tank.
  • Hot water delay. Unlike combi boilers, regular ones take time to heat stored water. So they cause a delay in providing access to hot water.
  • Heat loss. Stored water in the cylinder may lose heat over time. As a result, they can possibly lower overall boiler efficiency.

Now, think about which boiler is your best fit. Once you review both pros and cons, you’ll be able to make a better choice. But if you want to replace conventional boiler with combi cost, it is easier to do so.

How regular boilers get the job done

Now, these boilers take a classic approach to heating and hot water. They’ve got a separate hot water cylinder in an airing cupboard. Plus they’ve got a cold water storage tank, usually up in the loft. Now this boiler heats water that’s already stored in the cylinder.  So when hot water is needed, it pumps from the cylinder to the taps. 

For central heating, a regular boiler warms water and sends it to the radiators. It is true these boilers suit homes with high hot water demand. So if you’ve got a home that has many bathrooms, these can be the best choices to make. They, in fact, offer a higher flow rate than combi boilers. Yet, the cylinder and tank mean they need more space. Moreover, hot water can run out, needing time to refill and reheat. Despite that, several people have replaced conventional boiler with combi cost. The choice is yours.

Boiler efficiency

You can check your boiler’s efficiency by looking at its rating on energy efficiency systems, like ErP (Energy-related Products). So as per this system, ratings range from G (least efficient) to A+++ (most efficient). Moreover, an A+++ rating means 150% efficiency or higher. C to G ratings indicate 82% max efficiency, going as low as 30%. Consequently, high-efficiency boilers save money on heating bills.

Doubtless, boilers eat up 55-60% of yearly energy costs. To avoid high heating bills, get a highly efficient boiler. Further, efficient operation can save up to £1130 annually. Also remember, better efficiency reduces carbon emissions. It preserves fuel and the environment. So if you replace conventional boiler with combi cost, your wallet and the planet both will benefit.

Boiler performance

Consider the fuel your boiler uses. Average efficiency estimates for each type are:

  • Gas: 92–95%
  • Electricity: 99%
  • Oil and LPG: 92–95%
  • Biomass: 89–91%

For precise efficiency numbers, consult a heating engineer for exact prices and help in installing a new, highly efficient appliance.

Choosing a boiler installer

When picking an installer, check your home’s setup. Combi boilers offer a simpler installation. They don’t need extra components. So they’re perfect for urban homes with limited space.

On the contrary, conventional boilers involve complex pipework. Also, they’ve extra components. Consequently, they’re fit for older houses. Without reservation, they successfully meet the heating and hot water requirements of big homes with multiple washrooms. So always think about your home’s needs when choosing an installer. Moreover, think twice before you replace conventional boiler with combi cost. This is because installer quality and price may also differ.

Boiler Choices Simplified

Combi boiler highlights

  • Easy swap, needs minimal pipework tweaks.
  • Perfect for space-crunched homes.
  • Quick install slashes labour time.
  •  Might need a new cylinder or pipe expansion.
  •  A cold water tank sits up in the loft.
  •  Big homes with many bathrooms benefit from ample water storage.

Comparing Boiler Space and Storage

When sizing up space needs, it’s clear combi boilers are number one in compactness. Since they merge heating and hot water in a small unit, they often fit neatly into a kitchen cupboard. Truly this edge comes from the fact they don’t have a separate tank or cylinder.

In contrast, regular boilers need more room to settle down. This is because they’ve got a water tank in the loft and a hot water cylinder that occupies more home space. So if you’ve enough space in your home, you can handle the regular boiler’s components, especially the loft in a better way. Moreover, to replace conventional boiler with combi cost, do comparison of space and storage.

Combi boilers

  • No separate tanks. Ideal for small spaces.
  • Might struggle with multiple outlets.
  • Good for homes with tanks, and supplies with multiple outlets.
  • Needs loft space for the tank, requires an airing cupboard.

Ultimately, the choice is yours. It hinges on space. Got a small home? Purchase combi because it is for space-saving. Got a big house? Opt for a conventional for storage perks.

Combi vs. Conventional Boilers: What sets them apart?

Combi boilers do it all, heating and hot water in one unit. Conventional boilers, on the other hand, split the job, with a separate cylinder and tank. Moreover, opting for a combi means instant hot water and heating. But for a conventional one, you wait as it reheats the water. On top of that, regular boilers handle high water use better. So they’re perfect for larger homes having multiple rooms. But despite that, the majority of people like to replace conventional boiler with combi cost.

The Real Deal: Heating and Hot Water

Both boiler machines have different strategies for heating and hot water. Without a doubt, both efficiently meet needs, but their internal workings and parts are quite different. The efficiency of a combi relies on the pump that circulates hot water to home radiators. This is one perk. Next, water pressure stays strong even with simultaneous use. This is the result of relying on mains pressure. Plus, heating water on demand means no extra energy costs for storage. As a result, you can cut costs of energy usage.

Boiler Efficiency and Costs Explored

When checking boilers think now and later. A-rated combi boilers rock high efficiency, hitting 90-94%. Older systems? A mere 55% efficiency for central heating.

As a matter of fact, more efficiency means better savings. Indeed, efficient boilers turn more energy into heat. As a result, you can reduce your heating bills. Furthermore, opting for an efficient boiler isn’t just about money. It also means being eco-friendly.

Combi boiler replacement cost

Now, let’s talk about combi boiler replacement costs. Without a doubt, a new boiler can hit your pocket hard. Yet, tech-savvy combi boilers often boast a friendlier price tag. They’re easier to install without worrying about cold water tanks and hot water cylinders. But you shouldn’t stop at the price tag. Rather think of long-term benefits. Maintenance and repairs are factors too. Combi boilers, with fewer parts, often mean less upkeep. So, you can replace the conventional boiler with combi cost for the smartest home solution.

Water Flow and Pressure

Check how both type of these boilers handle hot water and changing pressure needs.

Combo boilers use direct mains pressure. So they’re great for strong showers. What’s more, they’re perfect for solo bathrooms. But keep in mind they might struggle with multiple taps.

  • Mains pressure: Direct use, excellent for high-pressure homes.
  • Pressure quirks: Best for single-use, may dip with multiple taps.

On the flip side, conventional boilers use gravity-fed systems, with a loft tank ensuring steady supply and pressure. So again they’re great for multiple bathrooms.

  • Low-pressure areas: Good for weak mains pressure, pumps boost flow.
  • Multi-use friendly: Handles many taps without pressure drops.

Heating and Hot Water

It’s time now to dive into where these systems differentiate the most. Let’s look at heating and hot water. Combi boilers, in fact, juggle both instantly. They need no storage cylinder. No doubt, they’re quick and efficient but might stutter when everyone in your family wants hot water.

  • On-demand hot water: Abundant for one, may lag with many users.
  • Space-saver: No tank means more room, great for warm homes.

These boilers on the other hand are perfect for big homes with multiple water needs. Stored in a cylinder, ready for all taps without a temperature dip.

  • Hot water stash: Big volume on standby, a steady supply guaranteed.
  • Multi-tap action: Handles many taps without a heat wobble.

So in homes with hot water hubs, these boilers are the best choice for consistent flow. But for smaller spots or low water demands, combi is quick and reliable. Plus they save energy.

Get a free combi or conventional boiler today

Whether you replace conventional boiler with combi cost or keep a conventional boiler, you may get them through free boiler grants. Yes, you read it right. UK government’s free boiler grants are available for landlords and private tenants. Moreover, we can help you to get your favourite boiler through an easy process. What you need to do is just enter your postcode here and we’ll deal with the rest. Under the ECO4 scheme, you may also be eligible for air-source heat pumps and solar panels. But all this depends on your home’s heating system. So check your eligibility today for the grant.


Choosing between combi and conventional boilers depends on your specific household needs. While combination boilers are popular in the UK, several people use conventional boilers too. Combi boilers occupy little space. Regular boilers on the other hand need extra room. You can get instant heat and water through combi, but a conventional boiler takes some time to meet your needs. Moreover, conventional boilers shine in big homes. They ensure a steady hot water flow for multiple bathrooms, even with lower pressure. The call? It all depends on balancing space, efficiency, and your household’s water needs.

Get Your ECO4 Grant

Simply enter your postal code and answer a few questions, we’ll handle the rest!

Recent Blogs

Share Blog

You May Also Like