Unfiltered, Uncensored Guide to Conventional Boilers
United Kingdom's Conventional Boiler Setup: Cost, Advantages, and Disadvantages (2025)
Hey there! Let's dive into the nitty-gritty of conventional boilers. You may have heard of them being called regular, heat-only, or traditional boilers. They're an old-school heating system for homes with a high demand for heating and hot water, particularly large homes with multiple bathrooms.
Here's a no-BS breakdown of everything you need to know about conventional boilers.
What's the deal with conventional boilers?
Simply put, conventional boilers provide heating but can't directly supply hot water for your taps or showers - that's why they're also called heat-only boilers. To do the whole shebang (heating and hot water), they need a cold water tank in the loft and a hot water storage cylinder in a cupboard or similar space.
Compared to combi boilers, which are sleek, singular units, conventional boilers take up more space in your home, but they offer the advantage of providing hot water for multiple outlets at the same time without any decrease in temperature or flow. Just keep in mind that if you use too much hot water, you'll probably need to wait for the cylinder to refill, which could take between 25 minutes and an hour.
Household size
How do those things work?
Energy output
A traditional boiler consists of:
Boiler unit cost
- Boiler Unit
- Cold Water Feed Tank
- Expansion Tank or Expansion Vessel
- Hot Water Storage Cylinder
Average cost (including installation costs)
The cold water from the tank in the loft feeds down to the boiler. This water deposit is usually placed as high as possible above the boiler for better water flow. When the boiler fires up, the heat exchanger inside warms the cold water, which is then pumped to the radiators or the hot water cylinder. Once in the cylinder, the water is further heated and stored to supply taps and showers as required.
There are two types of conventional boilers: open vent and sealed. The main difference lies in handling water pressure and air. Open-vent systems are open to atmospheric pressure, and they use a vent pipe to get rid of excess air and pressure. These systems require a feed and expansion tank to keep water level and account for expansion when water heats up. Sealed boilers use an expansion vessel to accommodate water expansion and are ideal for homes without loft space.
Small (1 - 2 bedrooms, up to 10 radiators)
How much do these buggers cost?
9kW - 18kW
The cost of a new boiler, including installation, in the good old UK can range between £1,600 to £5,500. The average cost for installation alone is around £3,550.
£600 - £1,600
Of course, there are factors that affect the price, such as:
£2,600
- Household size
- Energy output
- Type of fuel (gas, oil, or LPG)
You can find a breakdown of estimated costs based on the listed factors in the table below. Remember that these are just estimates - to find the best deal, compare quotes from at least three installers.
Medium (2 - 3 bedrooms, 10 to 15 radiators)
Household size | Energy Output | Boiler Unit Cost | Average Total Cost (including installation)----------------|--------------|------------------|------------------------------------------------Small (1-2 bedrooms, up to 10 radiators) | 9kW - 18kW | £600 - £1,600 | £2,600Medium (2-3 bedrooms, 10-15 radiators) | 18kW - 26kW | £700 - £2,200 | £2,950Large (4-5 bedrooms, 5-20 radiators) | 26kW - 40kW | £900 - £3,500 | £3,700
18kW - 26kW
Bear in mind that annual maintenance costs could run between £65 and £300, depending on the boiler manufacturer. Additional charges may apply for part replacements or extra maintenance work like power flushing. These costs can also depend on the availability of parts in your area.
£700 - £2,200
So, what's the good and bad?
£2,950
Pros:
- Handle high demand for heating and hot water
- Can be energy efficient (up to 94%) thanks to condensing technology
- Suitable for homes with low water pressure due to a gravity-fed water circulation system
- Easier replacement due to compatibility with older plumbing and heating systems
- Compatible with solar thermal panels for a greener heating process
Large (4 - 5 bedrooms, 5 to 20 radiators)
Cons:
26kW - 40kW
- Take up more space in your home due to additional components (cold water tank and hot water storage cylinder)
- Require longer installation times compared to combi or system boilers
- Hot water isn't immediately available (you'll have to wait until the cylinder refills if you use all the hot water at once)
- More expensive installation cost due to separate parts and the need for pipework adjustments
- Not as sustainable as low-carbon systems like heat pumps, biomass boilers, or solar panels, but they are less expensive for now
£900 - £3,500
Bottom line: should I get a conventional boiler?
£3,700
If your home already has a traditional heating system and needs upgrades with minimal costs, you have a house with several bathrooms, a high demand for heating and hot water, and enough space for the necessary additional components, then a conventional boiler might be the way to go.
If you want to reduce your carbon footprint, consider these low-carbon alternatives in the long run: solar panels, heat pumps, or biomass boilers. But if you're not ready to make that switch just yet due to technical or financial reasons, get yourself a modern, energy-efficient conventional boiler using condensing technology as a stepping stone.
And remember, for a hassle-free installation process, don't hesitate to contact local, vetted professionals. They'll save you the headache of contacting various installation companies. Simply fill out a short, 30-second form, and voila! You'll get up to three free and non-obligatory quotes from your area's most reliable technicians.
And that's a wrap! You're now well-versed in conventional boilers without any sugarcoating or controversy. Happy heating!
FAQ
What is a conventional boiler?
A conventional boiler is a traditional heating and hot water system suitable for large homes. Conventional boilers work with the help of an additional cold water feed tank (located in the loft above the boiler unit) and a hot water storage cylinder (placed downstairs).
Can a conventional boiler be an efficient replacement for an old, existing model?
Yes, a modern conventional boiler can be efficient and impressive in replacing an old, existing model. However, it may require extra space for components like feed tanks and hot water cylinders if they are not already installed.
What's the difference between a system boiler and a conventional boiler?
System boilers are considered a more compact version of conventional boilers as they draw cold water from the mains rather than a tank in the loft.
Do I have a conventional boiler if my heating system has a separate cold and hot water storage tank?
If your heating system has a separate cold water tank and a hot water storage tank, then it's a conventional boiler system.
How long do conventional boilers last?
Most conventional boilers have an average lifespan of 12-15 years, and they typically come with a warranty of between 2 to 12 years.
- For those seeking to minimize their carbon footprint and incorporate renewable energy sources in their home-and-garden, consider integrating solar panels with your existing conventional boiler system. Solar thermal panels can significantly reduce the amount of energy consumed for hot water production.
- In addition to solar panels, homeowners might also consider the installation of heat pumps to supply both heating and hot water. These devices use technology to transfer heat from the outdoor air or ground into your home, making them a sustainable alternative to conventional boilers. This lifestyle change would be an excellent addition when planning for home renovations or a new home in the house-and-garden sector.
){kind=link}