Picture yourself as the last one to shower, only to be greeted by a blast of cold water just as you’re lathering your hair with shampoo. This shortage of hot water is one of the telltale signs that it’s time to replace your water heater. This might lead you to consider tankless water heaters, which appear to address the cold-shower issue. However, you may be surprised to learn that these on-demand hot water systems sometimes struggle to meet your needs. Additionally, they come with a hefty upfront cost, particularly if you’re installing them in an older home. There’s also the ongoing maintenance to consider.
Deciding whether to replace your water heater with another tank unit or upgrade to a tankless model is not a straightforward decision. Weighing the pros and cons of each option can provide a clearer picture of what to expect. Some disadvantages of tankless water heaters might make you reconsider. If you’re still interested, understanding these drawbacks can help you take proactive measures to mitigate the negative impacts if you decide to proceed.
Tankless water heaters cost more initially
As reported by Angi, switching to a tankless water heater could set you back between $1,400 and $3,900, whereas traditional tank water heaters typically range from $600 to $2,500 per unit. Repair costs tend to be higher for tankless models compared to tank water heaters. While you might save on utility bills, your budget needs to account for the higher installation costs.
Installing a tankless water heater in an older home could entail even greater installation expenses. Electric models require a significant electricity supply to function correctly. If your home has a 200-amp service or less, the electrical system might struggle to support an electric tankless water heater. However, in some cases, 200-amp service may suffice. The power requirements depend on the size of the specific tankless water heater you select and its power usage, as well as other electrical demands in your home.
If your home’s electrical system can’t handle the power demands, an upgrade might be necessary, involving a professional electrician and additional costs. Upgrading to a 300-amp service could cost between $1,800 and $3,500, according to Angi. Increasing to 400-amp service usually costs between $2,000 and $4,000. An electrician can assess your system to determine if it can support a tankless water heater or if an expensive upgrade is needed.
There may not be enough hot water
The advantage of a tankless water heater is that it heats water as needed, providing an instantaneous supply. However, there are limits to how much hot water the unit can produce at any given time. The average production rate ranges from two to five gallons of hot water per minute. While this is typically sufficient for one person showering or an appliance requiring hot water, your needs might exceed these rates if you’re engaging in multiple hot-water activities simultaneously, like showering, washing dishes, and running a washing machine.
A shower alone requires about 2.5 to 3.5 gallons per minute. Dishwashers typically use one to three gallons per minute, while washing machines need two to four gallons per minute. You might need to balance your activities to ensure adequate hot water. If you have a large family, closely examine the flow rate of the water heaters you’re considering to understand how much hot water they can produce. Gas-fired tankless models generally have higher flow rates than electric ones, so opting for gas may lessen the competition for hot water. Another solution is to install additional point-of-use water heaters for specific areas or appliances, providing a dedicated hot water source to those high-use areas.
Hard water can be a problem
Do you notice dry skin, spotty dishes, and rough clothes? You may have a hard water problem, which can cause issues throughout your home, including in a tankless water heater. You can test your water’s hardness with a water hardness test kit, but you might already recognize the signs and be aware of the excess minerals in your water.
Those dissolved minerals can cause damaging buildup inside a tankless water heater. The heat from the water heater draws minerals from the water, allowing them to crystallize as scales inside the pipes, heat exchanger, and other components, potentially causing major issues. Overheating is a common problem if scale deposits affect the heat exchanger, possibly causing the water heater to shut down. You might also notice restricted hot water flow due to build-up in the pipes.
If you have hard water, installing a water softener before the water heater may help. This device removes minerals to prevent scale buildup inside the water heater. High-pressure water heaters also reduce sediment settling in the unit since the pressure pushes everything through the pipe quickly. It’s also possible to descale your tankless water heater with vinegar if you have hard water. If you don’t want to descale it yourself, schedule a professional descaling service with a local plumber.
Tankless models require more maintenance
Proper maintenance of your tankless water heater involves several key steps. Tankless units typically have filters that need regular cleaning or replacement, including the water filter, which helps remove sediment from the water. Changing this filter every six months ensures its effectiveness. The system may also have an air filter in the air intake that requires cleaning or replacement. It’s beneficial to inspect the air intake for blockages, corrosion, or other damage.
Regularly flushing the system to remove sediment that could clog or damage components is crucial. It’s recommended to perform this step at least once a year, though every six months is preferred if you have hard water or use a large amount of hot water. Conventional water heaters also benefit from regular flushing, at about the same frequency as a tankless unit. Once a year is usually sufficient unless you have a large family or hard water.
While maintenance demands are similar for both types, tankless models may require a bit more upkeep. Neglecting maintenance on either type of water heater can lead to wear or damage necessitating repairs. However, repair costs for a tankless model are likely higher compared to a standard tank water heater.
You could experience a cold water sandwich
A cold water sandwich might sound like lunch, but it’s actually a phenomenon you could experience in your kitchen. It occurs when you receive hot water immediately, followed by a burst of cold water before it turns warm again. The cold water is sandwiched between the warmer water. When this happens, you might assume your water heater is malfunctioning, but this can be normal, albeit annoying.
This issue arises from how the system operates. Tankless water heaters heat water on demand, but the heat exchanger may take a moment to warm up. If warm water remains in the faucet or pipes, it will flow out right away when you turn on the tap. However, cold water may also pass through the heat exchanger or pipes without being heated, resulting in the middle cold burst. The water heater then quickly heats the water to the correct temperature. This effect is more common with electric models since they take a bit longer than gas heaters to warm up.
Other potential causes of temporary cold water bursts include using multiple water sources simultaneously. Mineral buildup from cold water could decrease the heat exchanger’s efficiency. If you have a gas water heater that frequently produces fluctuating hot and cold water, the gas line might be too small to provide adequate fuel to the appliance. While there are advantages to tankless water heaters, it’s clear they also have numerous downsides.
