1. Unlimited Hot Water:
The most significant benefit of having a tankless water heater is the unlimited water. Only for this reason I highly recommend buying one. If you have a relatively large family, and one or two family member takes a shower, you could be sure that there is no more hot water left. You have to wait for hot water as a tanktop water heater takes time to heat water.
Note: By using a tankless water heater, you get unlimited hot water, Not instant hot water. For instant hot water, you need to install a recirculating pump. Alternatively, you could buy a tankless hot water unit that has a built-in recirculating pump.
2. Longer Lasting Unit:
A typical tank-style water heater last maximum of 8-10 years. Whereas, a tankless water heater could easily last up to 20 years.
3. Space Savings:
Tankless water heaters are very compact. Typically its size is similar to that of a carryon suitcase. You can place it anywhere you like. Even you can set it outside of your house (Not recommended for areas where the temperature drops significantly, for example, New York, Connecticut, etc.).
4. Cost Savings:
It is the on-demand water heater. It heats water only when it is necessary. The tanktop water heater keeps water hot all the time, even when we don’t need it. This wastes energy. Tankless water heater saves 30-50% energy compared to a tanktop water heater.
Cons of Tankless Water Heater / Disadvantages of Tankless Water Heater:
1. Routine Maintenance:
A tanktop water heater does not need any maintenance over its lifetime at all. If you use hard water (typical for city supply water), you need to flush your tankless water heater once in a year. If you have a water softener system, you need to flush your tankless water heater at least 3-5 years. Flushing cost could range from $300-$500. However, you can do it yourself on the weekend, and it takes only 20 minutes. There are lots of youtube tutorial videos on how to do it.
Note: I consider it as a pro. As we regularly flush it, we get clean and fresh hot water. On the other hand, tank-style hot water could build up rust and scales inside.
2. Initial Cost:
The price of a tankless water heater is higher compared to the tanktop water heater. However, these units last twice longer than a tanktop water heater.
3. Sensitive to slow flow:
If there’s too much scale buildup in the pipes, faucet, or showerhead aerators are clogged, or a turned-down tap reduces water flow to about 0.3 GPM, these units automatically shut off.
4. Upgrade Electrical:
You need to upgrade electrical wiring if you want an electric tankless water heater. However, an electrical tankless heater does not last as long as a gas tankless water heater.