What is a Condensing Oil Boiler?

And modern condensing oil boilers turn more fuel into heat than non-condensing models. So if you have an old non-condensing oil boiler, it’s time to get a replacement.

If you still have a non-condensing oil boiler, we highly recommend upgrading to a condensing boiler to significantly improve your energy efficiency and your carbon footprint. The first step is to get quotes from multiple oil boiler installers.

Boiler Guide’s quote service helps you get up to 3 free oil boiler quotes from trusted installers. Any quote you receive is for free and comes with no obligation. Don’t wait to upgrade to a more efficient and money-saving oil boiler.

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What is a condensing oil boiler?

Condensing oil boilers work like any oil boiler. The oil is stored in a tank at the property and is as efficient as natural gas. When you need heating or hot water, oil travels from the tank to the boiler where it’s burned.

They achieve efficiencies of over 90%. So they use almost all of the heat made when the oil is burned. Non-condensing boilers let much of the heat they make go straight out the flue pipe. Which isn’t good for the planet or your heating bills.

By holding onto more of the heat, you won’t need the boiler on for so long. And it will burn through less fuel. That means you’ll be paying less to heat your home and won’t have to fill up the oil storage tank so often.

Does my next oil boiler have to be condensing?

All new oil boiler installations must be condensing. And this has been the case since April 2007.

However, it’s still possible to install a non-condensing boiler if certain conditions are met.

For this to be possible, installing a condensing boiler in your home must be too difficult or expensive. To decide this, an inspection will need to be carried out at your property.

A number of factors will be considered, such as building type, whether you’re moving the boiler and if the flue can be fitted inline with regulations. A score will be given for each of these and if this score is over 1,000 then a non-condensing oil boiler can be installed.

If a condensing boiler can be installed then it is by far your best option in terms of efficiency and reliability.

Types of condensing oil boiler

There are three types of oil boilers: combi, system and regular. The same goes for gas boilers too.

Combi boilers

The combi boiler is the most recent type of oil boiler. They’re compact, cost-effective and heat your home and hot water on demand. That means there’s no need for any tanks or cylinders.

The mains water supply feeds straight into the boiler and is heated as and when you need it. So there’s no waiting around for the cylinder to fill up with warm water again (a problem with system and regular boilers). The water is then pumped from the boiler to the radiator or taps.

System boilers

System boilers take their water supply directly from the mains (like a combi) but store hot water in a cylinder. This is great for homes with 2+ bathrooms and a high demand for hot water.

Regular boilers

Regular boilers go by many names. Conventional, open-vented and heat-only for starters.

They’re the oldest type of boiler and are most often found in homes built in the 1950s and 60s. But while they have been around longer than combi and system boilers, modern models are reliable and efficient.

However, you should only think of installing a regular oil boiler as a direct replacement for an old one. So if you have a combi or system boiler, rule out a regular boiler. This is because you’ll need a hot water cylinder and tanks in the loft as well as the boiler iself. So a large pipe network is needed to connect them all up.

When you turn the heating on, cold water is fed down to the boiler from a tank in the loft. The boiler then heats up the water before sending it round to the radiators.

Which type of oil boiler is right for your home?

Large homes with 2 or more bathrooms will need a system or regular boiler. They are far better at meeting high demand for hot water than a combi as they store hot water in a cylinder. If you have a regular boiler then you may want to move to a system boiler as you won’t need the tanks in the loft.

If you live in a smaller property with 1 bathroom then a combi boiler is perfect. They heat water on demand so you’ll have hot water available at all times and won’t need a cylinder.

Condensing oil boiler costs

A new condensing oil boiler can cost anywhere between £1,000 and £4,500. Before you add on the installation costs – around £500-£2,000.

The total you end up paying will depend on the manufacturer, model and output rating. As well as whether it’s designed for internal or external installation.

You may also need a new oil storage tank. They need replacing every 10-20 years and cost between £1,00 and £2,000.

If you have an old non-condensing oil boiler in your home, you could be wasting a significant amount of energy and money on your heating bills. The good news is, you can easily upgrade to a more efficient and cost-effective oil boiler by requesting quotes from local heating engineers.

With our free service, you can connect with trusted heating engineers in our partner network who specialise in replacing non-condensing oil boilers with modern, energy-efficient models. Get up to 3 quotes for free and compare prices, features, and warranties to find the perfect solution for your home.

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Brilliant service. Was getting a headache from other plumbers with extortionate prices. Saves a lot of hassle ringing around. Really pleased. Thank you.

Boiler guide is an excellent, quick & easy way to source businesses to provide quotes to have boiler replaced.

The guys that came round were very professional and polite told us everything we needed to know and left the area spotless thanks

Best condensing oil boilers

Combi boilers

Internal combi boilers

External combi boilers

Internal system oil boiler

Internal system boilers

External system oil boilers

While the system boiler itself can be fitted outside, the cylinder will need to be inside your property.

Regular boilers

Internal regular oil boilers

External regular oil boilers

These regular boilers can all be installed outside in a garden area. However, the hot water cylinder and cold water tank must still be within the property.

Why you need a condensing oil boiler

If you have an old non-condensing boiler then we recommend upgrading to a condensing boiler.

Not only do boilers lose their efficiency over time but non-condensing boilers are outdated. You’ll have a more reliable heating system, start saving money on your bills and reduce your carbon footprint. What’s not to like?

Disadvantages of oil boilers

Alternatives to heating oil

Oil is the most popular way to heat homes that aren’t connected to the gas network. But they’re not you’re only option. So you may want to consider the alternatives to an oil heating system.

You could turn to LPG. A type of gas that’s stored in a tank – much like oil. That way, you’d still have a boiler so wouldn’t need to get used to a new type of heating system. However, LPG is a little more expensive than oil.

If you’re keen to do your bit for the environment then a renewable heating system is worth thinking about.

Heat pumps are a renewable heating system that takes heat from the air or ground. Depending on whether you turn to an air source or ground source heat pump. And if you’re interested in a heat pump, you could pair it with your oil boiler rather than going all in. This will take some of the workload off your boiler and could cut your heating bills.

You could also pair your oil boiler with solar thermal panels. These panels absorb heat from the sun and use it to warm the water in a cylinder. Saving your boiler a job.

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Quickly compare 3 FREE quotes

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Brilliant service. Was getting a headache from other plumbers with extortionate prices. Saves a lot of hassle ringing around. Really pleased. Thank you.

Boiler guide is an excellent, quick & easy way to source businesses to provide quotes to have boiler replaced.

The guys that came round were very professional and polite told us everything we needed to know and left the area spotless thanks

Nick has a wide range of experience writing about conventional and renewable heating solutions, and is always increasing his knowledge by researching any new heating technologies on the horizon.