Under Sink (Point of Use) Tankless Electric Water Heater Buyer's Guide
For years, tankless water heaters have been gaining traction as a viable alternative to tanked water heaters. They require less energy, and when placed at the point of use, provide quick, hot water without any of the heat loss you may experience with other water heaters. Unlike whole house water heaters, this kind of equipment works to heat water for a specific amenity in your home.
But there are a lot of options on the market, and it’s important to know which one is going to be good for you. This guide will help you choose the best tankless electric water heater for under your sink based on flow rates, the temperature of your groundwater, and your electrical wiring.
Do You Even Need an Under Sink Tankless Electric Water Heater?
It’s true that under sink tankless water heaters can save you money, and they are often more convenient. However, they can be difficult to set up correctly.
You might need to replace entire lines and electrical systems to get the tankless water heater to work. If you can’t do that yourself, installation can get pricey depending on how much the experts in your area charge.
They can require a lot of maintenance as well, including water filters for hard water and frequent descaling to make sure that they’re working correctly. After all of that, you still might not get the result that you want. They are more energy-efficient, but it comes at a cost.
The reality is that you are rarely going to get the same temperature out of a tankless water heater as you do from a tanked one, and most homes are set up for tanked models. The convenience is nice, but the benefits hardly outweigh the hassle. In this sense, if your priority is cutting down on heating costs, this probably isn’t the choice for you.
So before you buy an under sink point-of-use tankless electric water heater, ask yourself if it’s something that you even need, or if there is a tanked alternative that might be less trouble in the long run.
Quick Tips
In a hurry? Let us help you navigate the world of under sink tankless water heaters with these quick pointers.
- Choose a water heater that fits under your sink and will work with your current electric and water lines.
- If you want hotter water, go with a higher flow rate and a higher temperature rise.
- Know the temperature of your groundwater.
- Don’t pay more than $250 for a great-quality tankless water heater.
- Don’t expect to run a whole bathroom off of one under sink water heater.
Under Sink (Point of Use) Tankless Electric Water Heater Features and Options
It can be a bit difficult to choose an under sink tankless electric water heater. There are a lot of different heaters to choose from, and they aren’t all created equally. Below, we’ve listed some of the most important things that you should look at when you’re shopping for a point of use tankless electric water heater.
Dimensions
When you are purchasing a water heater explicitly for installing it under your sink, dimensions are one of the most important factors to consider. You want to make sure that the heater is going to fit, and that all the connections are going to be in place for the long haul.
Make sure that you know how large the area under your sink is. Pick out a spot that works. If you keep other items under your sink, be advised that all tankless water heaters need some space because they produce heat.
Keeping this in mind can help you decide on the perfect tankless electric water heater for your sink.
Flow Rate
The flow rate, measured in gallons per minute (GPM), is a measure of how much hot water the heater can produce.
Tankless water heaters don’t store water until it’s ready to be used. Only so much water can be run through a heater at one time. These smaller heaters are mostly meant for a single sink or application at a time, so the flow rates for under-sink water heaters will be significantly lower than what you would expect for your whole home.
The larger this number is, the better time you’ll generally have. When you get up to about 2.5 GPM, you might even be able to use two sinks at the same time and get hot water in both of them. For a frequently used sink, use the under-sink heater with a higher GPM.
However, if you only use the sink or fixture every so often, you can feel secure in choosing a tankless unit with a lower GPM.
Voltage
Much like water pressure is important for some of these heaters, voltage is important too. When it comes to electric water heaters (or, indeed, any electric device), pay attention to voltage requirements. Each device has a required voltage that needs to be met for it to work correctly.
At the proper voltage, a tankless water heater will heat quickly and put out more hot water at once. It might even produce an endless stream of warm water. However, with a voltage too low, you aren’t going to get the same performance at all.
Ideally, what you’re looking for here isn’t a way to compare water heaters. Rather, you’ll need to make sure that you have the voltage in your electric connections to allow the water heater to work well.
Energy Factor
The Energy Factor or EF rating of a unit is a simple measure of efficiency. This is calculated based on the amount of hot water the unit will produce per unit of fuel (in this case, electricity).
This number is always presented as a decimal point. You should look for numbers above 0.90 for the most effective and efficient units. Essentially, the higher the EF number is, the more you’ll save. That’s because the heater will be able to put out more hot water with less energy than units with a lower EF score.
Temperature Rise
Temperature rise isn’t a complicated concept, but it is an important one. Your groundwater is going to have a basic temperature, warmer in the summer and colder in the winter. The temperature rise of a unit determines how much it will be able to increase that temperature.
For example, say your groundwater is normally at about 50 degrees. A tankless water heater with a temperature rise of 40-50 degrees can only produce water that’s between 90 and 100 degrees for you.
Cold water is no fun in the wintertime, especially if you live in a harsher climate. This is important to keep in mind as you choose a tankless water heater for under your sink. You want to choose one that will give you sufficiently warm water while also managing your expectations.
Warranty
For any large or expensive appliance, a warranty is extremely important. In most cases, if the unit fails in any way during normal use and correct installation, the company will honor the warranty and replace it.
During this warranty period, you can contact the company to get a replacement if your tankless water heater stops working. There may be additional clauses, and sometimes different parts of the machine may have separate warranties.
Temperature Display
A digital temperature display is available on some tankless water heaters. This will allow you to see how hot your water is, and in some cases, you might be able to adjust it to the temperature you need for any specific application.
If that’s a feature that you want, going with a tankless electric heater that has a digital display is the best option for you.
Wattage
Briefly, watts are a unit of electric power that measures how much energy a device releases per second. It’s another feature that you can use to determine just how powerful a tankless water heater is.
Much like voltage, a higher wattage on a tankless unit is nearly always better. It’s important to note, however, that these factors don’t necessarily tell you how good a tankless water heater will be. The mechanics are important, but build quality and material quality have more to do with the performance of a water heater than wattage or voltage.
Minimum Flow to Activate
Because these water heaters are tankless, they aren’t always running. The way that they save you power is by only turning on when you need them to.
To prevent you from having to flip a switch each and every time that you want hot water, tankless water heaters usually have a minimum flow requirement. This means that below a certain flow rate, it isn’t going to kick on and start heating your water.
So if you don’t always want to have your faucet on at full blast, you should choose a tankless water heater with a lower minimum flow requirement. Anything below 0.5 GPM will work well for washing your hands, and anything above that can get a little more touchy.
Required Breaker
Most of the tankless water heaters on our list require a specific type of breaker to work properly.
This breaker requirement is measured in amps. For most of these water heaters, it’s important that they are wired into a breaker because of their power consumption and heating elements. This value will tell you how big they require the breaker to be.
This can be a deciding factor if you know anything about your home’s electrical system.
How Do You Want to Use It?
Your choice of under sink (point of use) tankless electric hot water heater depends a lot on how you’re going to be using it.
Obviously, all of the heaters here are meant to be used with sinks. Even then, there are variations. The water heater you choose will depend on your frequency of use, preferred water temperature, and the type of faucet that you’re using.
- Frequent use: For sinks that you use a lot throughout the day, go with a tankless water heater that has a higher flow rate, voltage, and wattage. It’s also important to choose a higher energy factor when you’re trying to save money and water. For commercial sinks and bathrooms that a lot of people are going to be using, this is important.
- Infrequent use: If you aren’t going to be using the sink a lot, you can go with a lower flow rate and other lower specs as well. A tankless water heater can be convenient, but if it’s going in a sink that you won’t be using that often, consider going with a lower performance unit.
- Preferred water temperature: Want hot water all the time? You should go with a tankless water heater that has a higher temperature rise and a smaller minimum flow rate. This will ensure that you can get hot water faster.
- Type of faucet: For a normal faucet, you should be able to use any one of these under sink tankless water heaters. However, if you have an energy-saving or water-saving faucet, it’s better to go with a lower flow rate requirement.
How Much Do You Want to Pay?
At the low end, you’ll be spending at least $100 on an under sink tankless water heater. Like most appliances of this caliber, you’re getting what you pay for. When you pay more, you get better quality materials and often better performance.
For a quality under sink tankless hot water heater, you can expect to pay between $100 and $250. Anything priced at more than $250 might be advertised as a higher-quality tankless water heater, but it might not be worth the extra money.
