Can A Tankless Water Heater Work For The Whole-House?

Bathroom, Beginner Info, Tankless Water Heater

Can A Tankless Water Heater Work For The Whole-House
As an Amazon Associate, I may earn from qualifying purchases at no extra cost to you. All the products recommendation links on will navigate to Amazon

Frankly speaking, the first-time buyers are quite inquisitive about whether a tankless water heater unit alone would be sufficient to cater to the hot water requirement of an entire house or not.

Well, if you’re also struggling to find out a genuine and tangible answer to the query, then trust me, you’ve landed on the correct post.

In simple words, a whole-house tankless water heater would be sufficient for small to mid-sized homes but at the same time, there are strings attached to it.

However, in order to make an informed purchase decision, you need to be well-versed with the types and sizes of tankless water heater models else you might end up making a wrong purchase.

Does it make sense?

Can A Tankless Water Heater Work For The Whole-House?

Let’s start from scratch so that even a novice buyer can make a purchase decision on his own.

Tankless water heaters are broadly divided into two categories based on the type of fuel – electric & gas models.

Electric water heaters like EcoSmart could be a perfect choice for small-sized homes.

It can serve the water requirement of a couple of bathrooms and faucets without compromising the flow rate.

What size tankless water heater do I need?

Moreover, if there is a sudden surge in the hot water demand because of an increase of guests or family members then you can install under-sink tankless water heaters to reduce the pressure on the main heating system.

During the last couple of years, we’ve seen a sudden surge in the demand for electric tankless water heaters, especially in nuclear families.

When we dive deeper we found out that higher efficiency, low-maintenance cost, minimal standby loss, portability, durability, and most importantly, affordability are among the top reasons why our clients were upgrading to an electric tankless water heater from a conventional counterpart.

Is RHEEM PROFESSIONAL CLASSIC RTEX the best electric tankless water heater for the money?

In layman’s terms, a small-sized nuclear family can settle down with an electric tankless water heater for sure, that’s what our past experience says.

Based on the type of fuel, gas tankless water heaters can be further segregated into natural gas tankless water heaters and propane tankless water heaters.

Of course, gas tankless heaters are more powerful as compared to electric counterparts.

So, if your family is bigger in size and the demand for hot water is more than average then you should opt for these little beasts.

But, before making a purchase decision, make sure you’re well aware of the differences between a condensing and a non-condensing tankless water heater as it will give you an edge in making a purchase decision.

Also, have a quick look at the article on that talks about the top tankless water heater brands.

It’s always a good idea to have some basic information about the top brands and their offerings so that you can opt for the product that not only caters to your requirements but also falls well within your budget.

Moving further, tankless heaters can be categorized as indoor and outdoor tankless water heaters based on the place of installation.

If you’re a resident of cold climatic zones then I would suggest you should opt for indoor tankless water heaters.

On the other hand, for hot & humid climatic conditions, any of the two will serve the purpose.

You might be wondering what if my family’s hot water requirement is huge?

Well, in that case, I would recommend you should buy a commercial tankless hot water heater.

Nonetheless, before making a purchase make sure you’ve found out what size tankless water heater would do the trick for you.

Is the discussion very confusing?

So, if you’re not interested in doing the homework and have a shortage of time, then simply buy a whole house tankless water heater.

I’m damn sure it will serve the purpose until and unless your hot water requirement is really HUGE.

If I’ve to summarize in a single statement, then “YES” a tankless water heater can work perfectly for your whole house.

Pros and Cons of a Tankless Water Heater that Makes It a Perfect Choice For Your Home

Before we wrap up, I would love to walk you through some of the important pros and cons of a tankless water heater.

Our motive behind this is to make you self-dependent when it comes to making a purchase decision.

Does it make sense?

So, without any further ado, let’s begin…


To be honest, I’ve tried to the best of my capabilities to present to you all the pros of a tankless water heater that according to me will help you in making an informed purchase decision.

Endless Supply of Hot Water

A tankless water heater uses a heating mechanism that heats the water only when you require it which isn’t the case with a conventional tank-styled water heater wherein hot water is stored in the tank.

Since the water is heated only when you require it so the unit is capable of providing you with an endless supply of hot water.

However, there is a string attached to it.

If there will be a sudden surge in demand for the hot water that exceeds the unit capacity then, in that case, you might have to deal with a decreased flow rate.

In layman’s terms, until and unless, the hot water demand is well within the capacity of the tankless unit, you can expect it to provide you with an endless supply of hot water.

Longer Lifespan

In general, a tankless hot water heater can last more than a decade only if it is maintained properly.

A longer lifespan is definitely one of the reasons for our clients to opt for these little beasts.

Since hot water isn’t stored in a tank so problems related to the tank including rusting, corrosion, etc are almost minimal.

Special Financing & Tax Breaks

The best thing about a tankless water heater is that it qualifies for the federal tax credits which definitely helps in offsetting the steep installation cost.

As of December 2016, the federal government offered a 10% tax credit on the overall cost of buying and installing a tankless hot water heater.

Energy Star-certified traditional storage heaters also qualify for the same 10% tax break.

Minimal Standby Heat Loss

As discussed earlier also, the standby heat loss in a tankless water heater is almost minimal since it doesn’t store hot water in a tank rather heat it on-demand.

On the other hand, in the case of a traditional tank-styled hot water heater, water losses heat to the environment due to differences in temperature.

Longer Warranties

Most of the top brands offer a longer duration of warranty which clearly depicts the trust and confidence that the manufacturers possess in their offering.

The longer the warranty the better it is.

Warranty can even run up to 20 years which is definitely something to brag about, isn’t it?

Lower Maintenance Cost

Yes, you guessed it, right.

In general, the maintenance cost of a tankless water heater is quite less, thanks to the mechanism and design.

It doesn’t use any sophisticated mechanism of heating the water so that users don’t have to spend a fortune in maintaining it.

Moreover, lower maintenance costs also add up to a longer lifespan as homeowners don’t hesitate in expediting the maintenance on a regular basis.

It doesn’t consist of a tank so maintaining a clean and debris-free tank wouldn’t be a task that you need to get involved in while expediting the maintenance process.

Did I make my point?

In the name of annual maintenance, all you need to do is to run a water softener.

Moreover, in order to reap maximum benefits as well as prevent mineral buildup, you need to flush out your system annually.

Higher Efficiency

Most importantly, tankless water heaters are highly energy efficient.

If I’m not wrong then a tankless hot water heater reduces energy uses by up to 34 percent as compared to a conventional tank-styled water heater.

So, it will pay for itself in the long run.


Like any other product, a tankless water heater comes with its own sets of cons that you must be aware of before making a purchase decision in order to safeguard yourself against false claims.

Higher Initial Cost

The upfront cost of a tankless water heater is higher as compared to tank-styled conventional heaters.

Furthermore, the higher cost is attributed to advanced technology, longer lifespan, lower maintenance, convenience, and durability.

On top of it, the install cost is also quite high.

So, if you’re on a shoestring budget then most probably, you should opt for a conventional water heater.

Cold Water Sandwich

If you failed to do the sizing of your tankless water heater correctly then you may have to experience a cold water sandwich.

Coldwater sandwich is a phenomenon in which you’ll feel an initial surge of warm water followed by cold water which quickly turns into hot water – NOT so good experience, right?

Needless to say, the cold water sandwich isn’t a big issue at all.

However, it may throw you off in case, you’re NOT used to it.

Inconsistent Water Temperature When Multiple Taps/Showers/Appliances Are in Use

I’ve time and again emphasized the sizing of a tankless unit.

Incorrect sizing can lead to several problems including inconsistent water temperature when multiple taps, showers, and appliances are in use simultaneously.

Again, I’m reiterating if you’ve done the sizing correctly then the occurrence of such issues will be less.

In layman’s terms, when you’re showing for a tankless water heater the key metric that you need to look for is flow rate.

Flow rate can be defined as the amount of water that a tankless water heater can heat at a given point in time.

It is measured in Gallons Per Minute or GPM.

The higher the GPM the better it is.

Below is the chart that clearly depicts the average flow rate of some of the most commonly used instruments in a house.

Outlet  Average Flow Rates (GPM)
 Bathroom Faucet .5 – 1.5
 Dish Washer 1 – 1.5
 Kitchen Faucet 1.5
 Washing Machine (Clothes) 1.5 – 3
 Shower 2.5 – 3

Wrappin Up

First and foremost, I would like to thank you for being with us till the end.

Secondly, I would like to bring to your notice that I along with my core team have put loads and loads of effort into coming up with this idiosyncratic superlative piece of information.

And, in case, you liked our effort and want to appreciate us then please do share this post with like-minded people and the ones who are in search of it.

After all, sharing is caring, isn’t it?

Cutting long-story-short, a tankless water heater can definitely work for the entire house ONLY IF sizing is done correctly.

That’s all, as of now 🙂

[Also Read]