July 30, 2021

Vented System Boilers

Homes will need a new boiler every 10 to 15 years to ensure they are safe and running efficiently, but this can put a lot of pressure on homeowners.

Vented System Boilers

Homes will need a new boiler every 10 to 15 years to ensure they are safe and running efficiently, but this can put a lot of pressure on homeowners. When the time comes for you to get a new boiler, there are various things you need to consider in order to get it right, and one of the most important is the type of heating system your home requires.

The kind of heating system that you have in your home can affect your energy bills, as there will be some boilers that allow more control over hot water and run more efficiently than others. Depending on several main factors, the right kind of boiler for your home can vary, which is why we offer a good range to our customers.

In this article, we are going to guide you through a particular kind of heating system that may be a good option for your home.

What Is An Open Vent Boiler?

Open vent boilers, also known as heat only units, are a kind of central heating system that allows control over hot water in your home. This is a conventional heating and hot water system that is found in older properties across the country, but they are still a viable option for those who need a new boiler now.

There are some key differences between the way a heat-only boiler works compared with an open vent system and other boilers with a sealed system.

Vented systems can only be used with heat only boilers. This is because they require water storage tanks, which means they cannot be used with a combi or gas boiler. Heat only boilers, or regular boilers, can also use a sealed system, similar to that used by a combi, but typically a vented system is the best option here.

A vented central heating system allows for a lot of hot water as they have a great capacity. Due to their water tanks, an open vent boiler can provide hot water to multiple bathrooms at once, which is not something a combination or gas system can do without impacting the water pressure or temperature.

It is these water tanks that make an open vent boiler differ from combi boilers because they can only supply hot water if the tanks are full.

When using heat only boilers, or regular boilers, with an open vented system, you will need to wait until the water tank is refilled before you can get any more out of it. Gas and combi boilers do not have a waiting period like this, but this does not mean that an open vent system is not a good option for your home.

How Does An Open Vent Boiler Work?

Open vent boilers have a feed and expansion tank which will be located at the highest point of the system.

They require this tank as well as an additional water storage tank to provide heating and hot water to your home. Unlike a combi, they are not compact units which is why they are most commonly found in lofts where there is space for the two water tanks and open vent system to be fitted.

An open vent system works exclusively with regular boilers, also known as heat only units, because of the water tanks required in the systems.

To provide hot water to your home, this feed and expansion pipe is the main player. The cold water storage tank is connected to the mains supply of your property, and it feeds water to this feed and expansion pipe, where it goes through the hot water cylinder when hot water is needed.

The cold water storage tank needs to have a constant level of water to provide hot water and heating at all times. Water in this tank is heated by the hot water cylinder to meet the demands of your home, and it can only do this when the tank is full.

As water becomes heated, it expands, and it is this increased volume that the feed and expansion pipe feeds back into the system via the hot water cylinder.

The open vent part of this heating system is a safety mechanism. This pump vent rises from the heating system of conventional boilers and goes above the water tank, where excess pressure is released to prevent overheating.

This means that to have an open vent system boiler installed in your home, there needs to be room for the hot water cylinder, the water tank, and the open vent pump to ensure it runs safely. This is why commonly, these heating systems are found in the loft.

Why Choose Open Vent Boilers?

Unlike a combi boiler, an open vent system requires a lot of room. In a combi boiler, the stainless steel heat exchanger is fitted inside the unit, allowing for a compact shape. An open vent boiler requires a hot water cylinder as well as a separate water tank which covers more room.

The system is commonly installed altogether in the lofts of homes, but the heating systems can be split up so they can fit into smaller spaces. The hot water cylinder required by a regular boiler can be put in an airing cupboard, separate from the water storage and open vent of the heating systems, which can make it suitable for smaller homes. This will be stainless steel or another durable material that is corrosion-resistant to ensure it lasts a long time.

As long as the boiler is vented well, it can be put in most properties, and we have a good boiler range available on our website for you to consider.

There are pros and cons to a vented system boiler, but they are the best option for homes with high demands for heating and hot water. This means homes with multiple bathrooms, as these conventional vented systems can provide a high supply of hot water and can even allow multiple outlets to be used at the same time.

With this conventional vented system, you can have the shower on at the same time as other taps around the home are being used without affecting the water pressure or temperature.

This efficiency is the reason why open vent boilers are still popular and maybe a better option for your home than a condensing or combi system.

The temperature of the water will be the same across all bathrooms in the home when the water tank is full, making open vented systems highly efficient for larger homes. They can provide hot water to the taps, as well as heating to every radiator.

There are options for how many litres the water tank can hold within our boiler range. The litres capacity of an open vent system can impact the size of the boiler and its efficiency.

Our boiler range has high ERP ratings for energy efficiency, and almost all of our boilers have an ERP rating of A. Considering the energy efficiency of your boiler can help you save money, as those with a higher rating will be cheaper to run.

Is An Open Vent The Best Boiler Type?

We have already highlighted some of the benefits of open vented boilers, but these are not the only options you have as a customer. While an open vented system could be the best one for your home, there are other options out there for you to consider.

If you have the space required for an open vent boiler, then this can be a great choice to make. Space is required for the two water tanks and the open vent required by this system.

Homes that have multiple bathrooms and a radiator in every room could benefit from the installation of an open vent boiler because of how much heat they provide.

It is possible to run the shower and wash the dishes at the same time when using an open vent boiler, as the water tank will make sure that there is no change to the water pressure or temperature when doing this.

The supply of heat and water comes from the mains of the property, making them an efficient option for most homes.

We can deliver and install a new boiler system to your home, whether you are replacing an existing system or need something brand new. Our installers are registered gas safe, and all boilers come with a 10-year warranty as standard.

This is something we offer for all of our boilers, so we can help you find something suitable for your home no matter your needs. A free quote is available for our products, so contact us online today.

Overall, if you have a large home with multiple radiators and bathrooms, then an open vent boiler may be the best option for you. Compared to gas, condensing, and combi boilers, they can provide a good demand for hot water without impacting the pressure of any outlet.

For homes that do not have a loft space, installation can be difficult, which is why we offer other kinds of boilers online.

We can install an open vent in the loft of your home if you have space. Learn more through our free quote given online to new customers.

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Finding The Best Boiler for Your Home

When it comes to finding the right boiler for your home, there are various factors to consider. We can provide a free quote to our customers to help them in this process, which can take some of the pressure off when shopping for a new heating system.

To find the right boiler for you, consider:


As we have mentioned, there are various types of boilers and heating systems to choose from. Each has its own benefits depending on the needs of your home. You can choose from open vent, condensing, gas, and oil.

Installation of all boilers is completed by a registered gas safe installer from our team to ensure the highest standards.


We have a great range of boilers available from brands such as Worcester & Viessmann. Worcester is one of the biggest names in the industry, and we offer a range of their boilers online.


The size of a boiler will determine how many radiators it can provide heating to and how much hot water it can offer.

Energy Efficiency

How efficient a boiler is can determine how expensive it will be to run. All of the boilers we offer have an energy efficiency rating of A which means they can help you save money when using them for heating or hot water.

All products will be installed by our professional, gas safe registered installer team. All boilers come with a 10-year warranty as standard, which gives you access to an installer should issues arise, such as corrosion, over this time.

To learn more about what we offer, see our catalogue or request a free quote.

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