What is a vented hot water cylinder?
Posted: 15th December 2024
| Author: Jamie Brown
| Category: Heating
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After recently covering how hot water cylinders work and what they are, we thought it would be useful to expand on this topic by focusing on vented hot water cylinders and how they differ from unvented systems.
If you’re not sure whether to choose a vented or unvented cylinder, this guide is for you. We’ll take you through the main differences between vented and unvented hot water systems and the pros and cons of each so you can make an informed decision.
What is the difference between a vented and unvented cylinder?
In a nutshell, the main difference between a vented and unvented hot water cylinder is that a vented system is connected to a cold water tank in the loft by a vent pipe and the unvented system is hooked up to the cold-water mains.
Let’s take a look at each type of system in more detail, along with its unique advantages and disadvantages.
Vented cylinders
Vented hot water cylinders are hot water storage tanks that are used in traditional plumbing systems. If you have a vented hot water cylinder, it will be connected to a cold water tank in the loft by a vent pipe. The water flows through the vent pipe down to the hot water cylinder where it is heated.
This type of system relies on gravity to deliver water to the cylinder. The water pressure you get with a vented cylinder depends on how high the cold water storage tank is. The higher the tank, the greater the pressure will be. That’s why you’ll usually find the tank in the loft.
Below, we explore the key benefits and drawbacks of vented hot water cylinders.
Advantages of vented cylinders
- Easier to install - Unlike their unvented counterparts, which require specialist installation by a G3 qualified engineer, vented cylinders are simple in design and easy to install, saving you time and hassle.
- Maintenance-free - Vented systems require little to no maintenance so they’re perfect if you’re looking for a ‘fit and forget’ solution.
- Cheaper - Because they’re simple to install and are virtually maintenance-free, vented cylinders usually work out as the more affordable option. If you’re on a tight budget, this fact might tip the balance in favour of a vented system.
- Reliable - Vented cylinders use proven technology that has been around for decades so they have a very reliable reputation.
- Good for larger homes and businesses - If you have two or more bathrooms, a vented cylinder may be recommended due to the fact that cold water storage tanks can provide a lot of water at once without affecting the water pressure.
Disadvantages of vented cylinders
- Lower water pressure - Unvented systems are maintained by the mains water supply, which is usually higher and more consistent than vented systems that rely on gravity. This means that your water pressure is likely to be lower if you go for a vented hot water cylinder.
- Requires more space - Because vented systems need space for both a cold water storage tank and a cylinder, these systems take up more space than unvented models.
- Risk of contamination and freezing - Because they are not closed systems, vented cylinders carry a risk of contamination and are more prone to freezing in the winter.
Unvented cylinders
Unlike vented systems, unvented hot water cylinders are connected directly to the mains water supply. The cold water is delivered from the cold water mains supply and is heated by the cylinder. They don’t require a separate cold water storage tank.
Unvented cylinders are newer than vented systems but they are growing in popularity.
Below are some of the main pros and cons of unvented cylinders.
Advantages of unvented hot water cylinders
- Better pressure performance - If you’re looking for consistently good water flow rates, unvented systems are an excellent choice. Unvented hot water cylinders outperform gravity-fed vented models by offering mains-level hot water pressure at all times.
- Space-saving - With unvented hot water cylinders, lack of room is no issue. With no need for a separate cold water tank, these compact systems are appealing for smaller homes and businesses.
- More energy efficient - Because they take water directly from the mains supply, unvented systems use less energy than vented cylinders.
- Sealed system - Unlike vented systems which can be at risk of contamination and freezing, unvented systems are completely sealed so aren’t associated with these issues.
- Quieter operation - A closed system also results in less noise.
Disadvantages of unvented hot water cylinders
- More difficult to install - Unvented systems are more complex in design and require specialist installation by a G3 qualified engineer.
- Require more maintenance - Unlike vented cylinders which require very little maintenance, unvented systems must be serviced every year to ensure they continue to operate safely and efficiently.
- More expensive - Requiring specialist installation and yearly maintenance means that these systems can cost more in engineer fees.
Looking for further information or advice on hot water cylinders? Contact our friendly and knowledgeable team today.
The Author: Jamie Brown
From my early working life as a labourer, then becoming a builder and a property developer, I have been buying and using building materials for over 25 years.
I set about to start a builders merchant which can offer high-quality products and significant savings along with speedy delivery to keep your sites moving.
Still having a foot in the construction industry on my own property, I always make sure the products we sell are up to our high standards which is important for us to keep a great image for the company and superior reputation to supply quality!
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