Copper vs stainless steel hot water cylinders

Posted: 8th December 2024 | Author: Jamie Brown | Category: Heating

If you’re investing in a new hot water cylinder, you’ll no doubt want to be sure you’re choosing the right one. After all, these components play an important role in ensuring the availability of hot water in your home or business.

When it comes to the materials used in their fabrication, there are two main types to choose from: copper and stainless steel. But which one should you choose? And does the choice of material really matter?

In this blog post, we take a look at the unique benefits and drawbacks of both copper and stainless steel hot water cylinders to help you make an informed decision.

Copper hot water cylinders

When the first vented hot water cylinders were created, copper was the material of choice and it is still an option for anyone looking to invest in a new hot water cylinder today. Copper is still used in the construction of vented systems and this is down to how hot water cylinders work.

Vented systems draw water from a cold water storage tank in the loft before heating it and copper is usually chosen due to its high heat conductivity. And because these systems don’t use mains water, they don’t require the superior strength of stainless steel.

But why might home and business owners choose copper hot water cylinders over stainless steel systems and what might put them off? Let’s take a look.

Advantages of copper hot water cylinders

• Heat transfer - Copper is a highly thermally efficient material. In fact, it can conduct heat around 20 times faster than stainless steel.
• Efficiency -  Because the water is heated rapidly, less energy is required - which is good news for the planet and your pocket.
• Malleability - Copper can be bent and shaped if required for installation without affecting the system’s integrity.
• Safety - Copper has antimicrobial properties. This means that it can kill bacteria that causes infections. This makes it a good option for hospitals, care homes or households with sick, elderly or immunocompromised residents.
• Recyclable - Copper is one of the few materials that can be recycled without losing its integrity or performance capability. It also holds its value as a scrap material.

Disadvantages of copper hot water cylinders

• Lower tensile strength - Although copper is a durable material and able to withstand high pressure, it is not as strong as stainless steel so is a less suitable material for mains-fed systems.
• Larger upfront investment - Copper is a more expensive material than stainless steel so a copper hot water cylinder is likely to cost more upfront.

Stainless steel hot water cylinders

The use of stainless steel in hot water cylinders is a relatively recent development. This material is usually found in unvented cylinders (i.e. cylinders that are connected to the mains water supply). Below, we discuss some of the main pros and cons of this material in the construction of hot water cylinders.

Advantages of stainless steel hot water cylinders

• Higher tensile strength - Stainless steel is about 2.5 times stronger than copper. It is able to withstand consistently high pressures, making it a perfect material for coping with the mains pressure of an unvented cylinder.
• Corrosion resistance - Stainless steel performs a little better than copper when it comes to corrosion resistance. This makes it an especially good choice for hard water areas. This is because the high mineral content of the hard water can scale and corrode pipes and hot water systems.
• More affordable upfront - This material has a lower price point than copper, so you’re likely to pay less upfront if you choose a stainless steel hot water cylinder.
• Longer lifespan - Because of its strength and resistance to corrosion, stainless steel hot water cylinders are often associated with longer lifespans. This makes them an attractive option if you’re looking to save money in the long run.

Disadvantages of stainless steel hot water cylinders

• Less efficient - Although stainless steel offers a longer lifespan, it is known to be less efficient than copper as it doesn’t conduct heat as well. This means that more energy is required to heat the water. In turn, this can make stainless steel systems more expensive to run.
• Less flexible - This material is harder to work with if you need to bend it or shape it for installation. It also costs more to make bespoke one-offs.

For further help or advice on choosing a hot water cylinder, get in touch with our friendly and helpful team.

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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