When you’re buying a hot water system you will either be getting one with a storage tank or without. This seemingly very simple factor is actually one of the biggest considerations you’ll have to make. If you are getting a hot water system with a storage tank it will either be referred to as such or it could be a hybrid system. If your hot water system doesn’t have a tank it will either be labelled continuous flow, instantaneous or tankless. There’s a lot more to consider if you’re looking at storage hot water systems, mostly surrounding what size tank to buy and what materials it is made of, but if you want it to last as long as possible, these are the things you will need to think about.
Most hot water systems use a tank
Most hot water systems use a tank. They heat and store water in advance so that you can have hot water fast and at a consistent temperature. It does take a while for the water in the tank to reheat though, so you need to choose a tank size big enough to suit your household’s hot water needs. Naturally, having a hot water system with a tank will take up more space depending on its capacity, and if you’re choosing a gas storage or solar hot water system there are other installation requirements.
Your choice of what your storage tank is made of is usually stainless steel or vitreous enamel. A stainless steel tank is more expensive but they usually last a lot longer and require less maintenance. You will still need to replace your valves and seals every so often but stainless steel tanks often come with a 10 year warranty and they don’t have a sacrificial anode that needs replacing every few years. A sacrificial anode is a feature of vitreous enamel tanks and if not replaced in time can result in irreversible damage. These tanks are made of mild steel with a protective inner lining of spun glass polymer (vitreous enamel) that erodes over time. Vitreous enamel tanks usually come with a 5-10 year warranty.
Continuous Flow Hot Water Systems
A continuous flow hot water system heats water just as you need it. These systems are often cheaper to run than ones with a storage tank as you only heat what you need and don’t have to worry about heat loss. While called instantaneous they sometimes take a few seconds to get going depending on how far away the hot water system is from the tap you are using. As they don’t have a tank, capacity is based on flow rate and generally determined by the amount of taps you have rather than the number of people in your household. While warranties are also usually for 10 years a continuous flow hot water system has the potential to last you a lot longer than one with a storage tank.
You can also find hybrid hot water systems that combine some of the best features of each system. They come with a much smaller tank meaning less space required for install, but that tank is enough to provide you with back up hot water when you need it, such as times of high demand. The smaller size also allows for much faster reheating, as there is less water inside the tank that needs to be heated, so even after you use it you won’t need to wait long for it to be full of hot water once again. Solar hot water systems are often referred to as hybrid but are really just storage tanks with an instantaneous booster attached as back up. True hybrid systems are designed to last long, be highly energy efficient, cost little to run and have a lower environmental impact.
As with choosing the right energy source for your hot water system, choosing the right type to buy is often limited by what you can fit and afford. It’s still a good idea to think about your preferences though, as you will be better informed when you speak to a plumber and together can work out what the best unit for your circumstances is. Having this background knowledge can go a long way to ensuring the hot water system you buy is one you won’t regret, or be surprised by, later down the track when you discover something about it you should have known from the start.