Advantages
- Waste less water.
- Reduce energy costs.
- Not worry about water leak.
- Some have water re circular function build in.
- Take up less space.
- Longer life expectancy of as much as 20 years.
Disadvantages
- Expensive, more expensive than traditional water tank heater.
Upfront costs. Tankless water heaters will cost you twice as much as conventional storage tanks. A standard traditional tank-type water heater starts out at about $800. Standard tankless water heaters start out at about $1,600. - Special outside vent, need HOA approval. Keep in mind that tankless water heating units need good venting which can be costly.
- Special gas hookup, extra cost. Because tankless units have high-powered burners, they also have special venting requirements (a dedicated, sealed vent system, which requires professional installation). Natural gas burners often need a larger diameter gas pipe, which adds to the initial installation cost.
- Require permit.
- Only special plumber can handle the job.Retrofitting a home with a tankless unit which can be extremely difficult and costly. You will need a skilled plumber to do the job perfectly.
- In areas where there is hard water, there has got to be a water softener installed so you won’t ruin the tankless water heater.
- Some unit require waiting time and back order.
Sources:
https://ygrene.com/blog/tankless-water-heaters-10-pros-and-cons