The material used to manufacture heat exchangers determines the efficiency and durability of your plumbing appliances. Stainless steel heat exchangers have previously been the most desirable choice for these appliances, such as boilers. However, aluminium heat exchange has become an increasingly popular alternative for many reasons.

Stainless steel vs Aluminium heat exchange

There is a lot of debate regarding whether stainless steel or aluminium is the most effective material to use for heat exchangers. While both boast a range of advantages, by acknowledging their disadvantages we can come to a conclusion on which material is best.

Firstly, due to stainless steel frequently being used in many modern domestic appliances, it has an excellent reputation. Its strength, durability and high resistance to corrosion has resulted in it being a favourable choice for not only heat exchangers, but technologically advanced products too. Stainless steel heat exchangers are especially advantageous as they do not require the use of system inhibitors and are, in fact, compatible with plain clean water. This means there is little maintenance required in order for a stainless steel heat exchanger to remain in good condition. On the other hand, it should be noted that aluminium heat exchangers are more likely to suffer damage if they are not maintained regularly. However, this problem can be easily overcome using Plumbers Milton Keynes. Their years of experience and extensive knowledge of plumbing mean they can advise you on the most effective ways to maintain your heat exchanger. Keeping your aluminium heat exchanger in good condition is important as it will significantly improve its durability and efficiency.

While it is true that stainless steel is an excellent material to use for heat exchangers, aluminium is equally as effective, if not better. For example, the thermal conductivity of aluminium is four and a half times higher than stainless steel. It should also be understood the performance of stainless steel varies depending on the amount of chromium it contains. This means that unless the stainless steel is of a high grade, it will be a less effective heat exchanger. In comparison to stainless steel, it is also cheaper, lighter and arguably more effective at resisting corrosion. These are all important factors to take into consideration and will be explored in depth to give you a greater understanding of the benefits of aluminium heat exchange.

Thermal conductivity

The thermal conductivity of any metal has a direct impact on its heat transfer efficiency. So, if a material has the ability to transfer heat successfully, it will directly improve the overall performance of the heat exchanger. Aluminium is an excellent conductor of heat and can therefore successfully transfer the heat from the combustion gasses to the system water when used in a boiler.

Sciencing has an informative article which explores the difference between thermal conductivity in aluminium and stainless steel. Thermal conductivity is measured in watts per kelvin per meter, and when displayed in this format, it is easy to identify which metal has greater thermal conductivity. For example, aluminium has a thermal conductivity of around 45 watts per kelvin per meter whereas stainless steel has roughly a thermal conductivity of about 15 watts per kelvin per meter.

As mentioned before, it is beneficial to compare both materials in order to understand which makes the most effective heat exchanger. In terms of thermal conductivity, it is clear that aluminium significantly outperforms its steel competitor.

aluminium heat exchanger

Corrosion resistant

Corrosion is hugely problematic and detrimental to the functionality of your boiler. Causes of boiler corrosion include:

  • Unbalanced pH of boiler water
  • Oxygen present in boiler water
  • Exposure of boiler metal to dissolved gases
  • Improper and unscheduled maintenance
  • Carbon Dioxide present in boiler water

A corrosion resistant heat exchanger is key to the longevity of your plumbing appliance and will reduce the amount of maintenance required. Aluminium has become a highly desirable metal to use for heat exchangers due to its widespread use in the automotive industry. Typically used for engines and car bodies, it has the notable feature of a corrosion-resistant protective oxide coating. This protective coating makes aluminium a very popular material to use in the car and plumbing industry as it means the risk of rust is significantly reduced.

Flexible and versatile

Due to the popularity of stainless steel, and it previously being the primary material used for a lot of heat exchangers, it is surprising that it was actually aluminium that was used in the first condensing boilers ever produced. As a result, over 35 years of experience of aluminium-based heat exchangers already exist in the industry. Over these years, aluminium has been continually praised by many boiler manufacturers for its flexibility and versatility. In fact, one of its main benefits as a material used for heat exchangers is that it can be cast, increasing design possibilities. Moreover, it’s lightweight property makes it ideal for compact, wall-hung boilers.

boiler mounted to the wall

Cost effective

Manufacturers tend to favour aluminium over stainless steel as it is considerably cheaper. By keeping manufacturing costs low, the price of appliances can also be reduced. This means that by opting for an aluminium heat exchanger, you will be paying less but still own a high-quality product. Another way in which you could save money is to book an annual boiler service every 12 months. With gas safety inspections Milton Keynes, an experienced engineer will check your boiler is correctly installed, confirm that it is safe to use and make sure there is sufficient air supply. A thorough inspection of your central heating system can significantly reduce the chances of your boiler breaking down, increase its performance and potentially lead to reduced heating bills.

Understanding aluminium heat exchange

Just like all materials used in plumbing appliances, aluminium has both its advantages and disadvantages. However, now that you are informed of the benefits of aluminium heat exchange, we hope you will consider this when purchasing a new boiler. By fully understanding the importance of investing in an effective heat exchanger, you can use this to your advantage and find the best product for you.