# 7 Best Tankless Water Heaters In 2020 (Based On Specs)

The best tankless water heaters have numerous advantages over conventional water heaters. They offer on-demand hot water, last for 20 years (vs. 13 years for heaters with tank) and come with 2 distinct characteristics:

### #6 Sio Green SIO18 V2 (Infrared Electric Tankless Heater)

Sio Green V2 is a unique tankless heater; you might even say that it’s a next-gen device. While both electric and gas heaters heat up metallic parts of the heat exchanger in order to produce on-demand hot water, the Sio Green V2 heater uses Quartz elements and far infrared technology to do the same.

The combination of Quartz and the infrared spectrum is definitely interesting. For decades, NASA has been developing infrared heating technology. When applied to Quartz tubes (instead of metallic tubes), you can generate a high-temperature gradient across the Sio Green heating chamber. That, in turn, heaters the water very quickly and is environmentally friendly.

What is more, without the contact between water and metallic parts, you have no corrosion and no calcium deposits. This doesn’t only prolong the lifespan of the infrared tankless water heater but it also saves you a ton of maintenance problems.

Here is how the Quartz tubes look (they are located inside the Sio Green heater):

The far-infrared light that powers up the Quartz tubes is, in turn, powered by electricity. If we simplify things, the Sio Green is an electric tankless heater with NASA tech energy transfer from electrical power to the water heating.

For residential use, you have two choices of Sio Green V2 heaters: the smaller 9 kW model and the bigger 18 kW model. Most of the households do need the bigger 18 kW model which can achieve the maximum hot water flow of 6.6 GPM.

### #7 Noritz NRC66DVNG (Long-Term Cheap Natural Gas Heater)

Noritz NRC66DVNG is a compact and reliable gas tankless water heater. Of course, the big problem gas heater producers always want to resolve, is the lower energy-efficiency.

Noritz has managed to get the EF (a rating that determines energy-efficiency) beyond 0.90. In fact, the NRC66DVNG has an EF rating of 0.91. That is, broadly speaking, the same energy efficiency range as average-efficiency electric tankers.

On top of that, the Noritz NRC66DVNG is capable to heat the water up to 140˚F. This is the maximum temperature most households require. The maximum hot water flow is 6.6 GPM; a little bit on the lower side.

For some installers, having the ability to use the Schedule 40 PVC piping and fitting is an advantage. Frankly speaking, the Noritz NRC66DVNG tankless water heater does offer Schedule 40 piping, but that’s not an essential thing a good tankless heater installer would require.

The best thing about natural gas and high energy-efficiency are the costs. The Noritz NRC66DVNG costs less than $1,000 but during the lifespan of a tankless water heater, the price of hot water can reach up to$10,000.

The price of hot water is based on the energy price and the efficiency of the tankless water heater. The lowest price of fuel for a tankless heater is, and will likely be in 10 years and so on, natural gas. The 0.91 EF rating of the Noritz will take that natural gas and use it very effectively.

In the long-term, the Noritz is one of the cheapest ways how to get on-demand hot water.

#### Do You Agree With The Gas And Electric Tankless Heat Picks?

Some people have a great experience with a tankless water heater while others have a horrible one. If you own one of the heaters above, please do give us a short review in the comments.

If you have some other tankless heater to add to the list, especially those with high EF ranking, please let us know below.