Why Tankless Water Heaters May Not Be the Best Fit for Every Home
Tankless water heaters have become a popular upgrade in recent years. Many homeowners are drawn to the idea of endless hot water and improved efficiency. While these systems can be a great option in some situations, they are not always the best fit for every home. Before making the switch, it’s important to understand some of the potential downsides.
Higher Upfront Cost
One of the biggest drawbacks of tankless water heaters is the initial cost. Tankless systems typically cost 2-3 times more than traditional tank-style water heaters. In addition to the unit itself being more expensive, installation costs can also be higher. Many homes require electrical upgrades, gas line upgrades, or special venting to support a tankless system.
For homeowners on a budget, a traditional tank water heater is often a much more affordable option.
Gas or Propane Is Often Required
Most tankless water heaters installed in homes run on natural gas or propane. That’s because electric tankless water heaters require a very large amount of electricity to operate. In many cases, the electrical demand exceeds what a typical residential electrical panel can support without significant upgrades.
Because of this, most homes simply are not equipped to run an electric tankless water heater without major electrical modifications. Homes without access to natural gas or propane may find that installing a tankless system is not practical or cost-effective.
Limited Flow Rate
Tankless water heaters heat water on demand rather than storing it in a tank. While this provides continuous hot water, there is still a limit to how much water the system can heat at once. If multiple appliances are running simultaneously—such as a shower, washing machine, and dishwasher—you may experience reduced water temperature.
In larger households where several fixtures run at the same time, a single tankless unit may struggle to keep up without installing multiple systems.
Retrofit Challenges
Many homes were designed with tank-style water heaters in mind. Switching to a tankless unit often requires modifications such as:
- Larger gas supply lines
- New venting systems
- Electrical upgrades
- Relocating plumbing connections
These upgrades can quickly increase the overall installation cost and complexity.
Regular Maintenance Is Required
Tankless systems require regular maintenance to operate efficiently. Mineral buildup from hard water—commonly called limescale—can affect performance and shorten the lifespan of the unit if it isn’t properly maintained.
Electric tankless water heaters are particularly susceptible to limescale buildup because the heating elements come into direct contact with the water. This buildup can accumulate quickly and reduce efficiency or damage components if not addressed.
Most manufacturers recommend biannual flushes (twice per year) to remove mineral buildup and keep the heat exchanger or heating elements working properly. Skipping this maintenance can lead to reduced efficiency, costly repairs, and even voided warranties and is even more important in areas where the water contains high mineral content like ours.
Traditional tank water heaters are generally simpler and typically require less routine maintenance.
Higher Repair Costs
Because tankless systems use advanced electronics and specialized components, repairs can be more expensive compared to traditional tank heaters. Replacement parts and service calls may cost more, especially if a technician with tankless experience is required.
Not Always the Most Cost-Effective Option
Although tankless systems are often marketed as energy-saving solutions, the actual savings can vary. For homes with moderate hot water usage, it can take many years for energy savings to offset the higher purchase and installation cost.
When Tankless Might Not Be Ideal
Tankless water heaters may not be the best choice if:
- Your home has high simultaneous hot water demand
- Your plumbing or gas system would require major upgrades
- You do not have natural gas or propane available
- You want the lowest upfront cost
- You prefer simpler equipment with lower repair costs
Proper Sizing Is Critical
A tankless water heater must be properly sized for your home’s hot water needs. If it is too small, it may struggle to keep up during periods of high demand, leaving showers lukewarm or appliances running inefficiently. Conversely, oversizing a unit can lead to unnecessary costs without providing significant benefits. Working with a qualified plumber ensures your tankless system is correctly sized based on the number of bathrooms, appliances, and peak usage patterns in your home.
The Bottom Line
Tankless water heaters offer some great benefits, but they aren’t automatically the best solution for every household. In many cases, a high-quality tank water heater can provide reliable hot water at a lower cost and with fewer installation challenges.
The best option ultimately depends on your home’s setup, your hot water usage, and your long-term goals. A qualified plumbing professional can help evaluate your system, properly size a tankless unit if that’s the right choice, and recommend the water heater that makes the most sense for your home.