The benefits of stainless steel in hot water generation
With stainless steel becoming a popular choice for hot water products, we take a look at some of the key factors driving this trend.
What is stainless steel?
Stainless steel is a generic name for more than 150 carbon alloys that have a minimum of 10.5 chromium. Chromium makes stainless steel corrosion-resistant by oxidizing quickly, forming a thin layer on the metal surface that protects the underlying metal from corrosion. With this thin passive film completely covering the metal surface, the metal is passivized, and the risk of corrosion is greatly reduced.
The most commonly used grades of stainless steel employed in hot water generators are 304, 316(L) and duplex which have a higher level of corrosion resistance and the ability to shape and form the metal into tanks and detailed heat exchangers.
The battle against corrosion
When it comes to dedicated water heaters and hot water stores for domestic hot water, corrosion is the enemy, particularly wet corrosion. Wet corrosion occurs through an electrochemical oxidation reaction that requires the presence of oxygen. For example, steel interacts with water and oxygen to form hydrated iron (III) oxide–rust, which will eventually cause structural damage, resulting in costly maintenance and repair, unless otherwise prevented. Here, stainless steel provides high resistance to corrosion and provides consistent performance to stresses caused by harsh operating conditions, thus maximising the service life of the water heater or store.
Exceptional heat transfer
As with boilers, when it comes to dedicated water heaters and DHW storage vessels, materials are also best selected for their heat performance properties. As the heat exchanger plays a key role in maximizing effective and reliable heat transfer, stainless steel offers a robust long-lasting solution.
Frequently confronted with minerals, oxygen, chemicals and sediment, not to mention high temperatures, thermal stress and flue gas condensate, stainless steel is, without doubt, a strong, durable contender that can withstand water and fire side attacks. In comparison to heat exchangers made from steel or copper, which can struggle to withstand flue condensate, stainless steel is a good material choice due to its high corrosion and flexibility. Also, due to their composition of corrosion-resistant alloys, stainless steel products often have a longer warranty such as our market-leading five-year warranty.
Looking at the bigger picture
Often assumed to be more expensive than some of the other materials traditionally used, such as copper, aluminium and steel, when you look at the bigger picture and consider total life cycle costs, stainless steel is often the least expensive option.
Stainless steel water heaters and storage vessels also have the added advantage of being lightweight. Featuring a typically much thinner wall, this makes them much easier and safer to transport and install.
Lastly, compared with other commonly used materials, stainless steel has relatively low embodied carbon, which contributes to longevity and should be considered within the whole-life carbon impact assessment.
The recently acclaimed Dorchester DR-SG stainless steel condensing water heater ticks all the boxes when it comes to achieving a durable solution that will stand the test of time. Available in ten power outputs over three storage capacities, the Dorchester DR-SG features a durable full stainless-steel tank, heat exchanger and coil for increased performance, efficiency, and increased service life.
Offering enhanced durability with electrical anode protection, the DR-SG offers excellent performance, even under the most challenging water conditions. Acting as a ‘fit and forget’ part of the water heater while providing additional benefits, the anodes do not require any routine maintenance or replacement and have an estimated service life of more than 10 years.
Suitable for both renovation and new build projects, including locations with substantial and continuous hot water demands such as hotels and sports facilities, the Dorchester DR-SG meets all of the latest Building Regulations and offers significantly improved efficiency and performance when replacing a non-condensing water heater.