We moved into a house four years ago that had a tankless water heater. I’ve owned many traditional water heaters in previous homes and businesses. I’ve learned a lot about them and I think my experience might help you to decide whether a tankless heater is a good option for you. When you look for pros and cons you mostly find people trying to sell them, which isn’t an unbiased opinion.
First, let’s dispel a misconception about the tankless system. They do not deliver hot water on demand. When you turn on the hot water the heating element has to heat up. The heating element heats up and then the cold water runs through it. An electric element unit takes longer to heat than a gas model, just like a gas burner vs electric.
Traditional storage tank water heaters are on-demand water heaters, meaning they keep water hot and waiting at all times, so you have instant hot water. Because of this they have decreased energy efficiency.
Pros of Tankless Hot Water Heaters
Long Lasting – Tankless water heaters have a longer lifespan, they can last twenty years. Conventional water heaters have a life expectancy of about 10 years. A tankless model can last twice as long, so remember that when you are considering the type of water heater that is the right choice for you.
Less Damage When It Stops Working – Maybe you’ve never had this happen, but I have. The water heater leaks in the attic and suddenly water is flowing down through light fixtures and the ceiling.
Traditional water heaters can cause a lot of damage when they break, especially if you aren’t home. You can rig an alarm to notify you, but this doesn’t help if no one is there to shut off the water.
Did you know that if a conventional hot water heater is broken or leaking it will continue to fill up with water and flood your house until you shut off all the water? Do you even know how to shut off the water? I didn’t until it was flooding all over my house.
Maybe it was just me that didn’t know this. If I hadn’t been home when it first broke AND known how to shut the water off at the main valve (or the supply intake on the water heater) I would have had to replace all my wood floors and many other things.
In my experience, this is reason enough to go tankless. It outweighs the upfront cost of switching.
Energy Savings – All water heaters come in gas or electric. When you compare electricity usage Direct Energy reports that “tankless heaters are around 24 to 34 percent more efficient than heaters with tanks in homes that use 41 gallons or less of hot water per day, or 8 to 14 percent more efficient in homes have 86 gallons or more of water use. Gas water heaters are typically less expensive than electric models.
Smaller – Tankless water heaters have a compact size and take up a lot less space. This is often why you find water heaters in attics, they require a large storage tank that requires quite a bit of space. You can put a tankless unit beside your washing machine in most homes. There are also outdoor units that can be mounted on the side of your house (as mine is).
Cons of Tankless Water Heaters
More expensive – The initial cost of tankless water heaters ARE more expensive, but they last twice as long. If you are going to buy one I recommend getting multiple bids. I got one bid for $7900 in 2019 and one for $2250. There can be a huge range. An 11-gallon per minute unit in 2022 is around $1800 (for a Rheem unit from Home Depot). It is significantly more when you make the switch from one type to another. A comparable conventional storage water heater is less than half that price.
Fewer Plumbers That Service Them – In my area there are fewer installers that install and maintain tankless water heaters. The professional plumber that installed mine would NOT come back to service it. Tankless water heaters require being flushed out every twelve to eighteen months, depending on whether you have hard water where you live. The harder your water the more often it needs to be flushed.
After waiting several months for my plumber to come flush mine out I went to google and discovered that it is not that hard to do, so I did it myself. I’ll explain how to do it yourself in a separate post.
Electric Vs Gas Tankless Water Heaters
Electric tankless units can heat eight gallons of water per minute. They are smaller in size. These are not the best choice if you have a large family or you plan to take a shower AND do a load of laundry on hot. Gas units generate more hot water per minute.
The plumber I use did NOT recommend electric tankless water heaters. I think this debate is not that relevant. If your home is already set up for gas it is a good idea, not to mention much more cost-effective to stick with the power source that is available, whether it’s natural gas or electric.
If I needed a new water heater I would switch to a tankless water heater in a minute. It might cost a bit more upfront, but I never have to worry about it flooding my house.