One day you will turn on your hot water and no hot water will flow out. Instead, you will get icy cold water.

Do you know what type of water heater to get when this day inevitably comes?

You could go the standard route and purchase a conventional water heater. However, a multitude of different options are available other than the standard water heater.

Unfortunately, finding a suitable alternative is often a painstaking process. You have to know the type of breaker in your home, the water pressure in your home, and the water demands of your home. Even worse, these don’t include a filter. If you want to filter your shower, then you need to purchase a filter for your shower.

You can’t simply go to Home Depot and pick out a water heater that you like.

This guide to buying a water heater will cover absolutely everything you need to know before your purchase. It will cover the different types of heaters available, the advantages and disadvantages of each type of heater, maintenance tips, and more.

The Different Types of Water Heaters

Water heaters come in a few different varieties. It’s more than just the massive hot water tank that you find in the vast majority of homes. In fact, there are at least five different kinds of water heating systems available on the market. We’ll cover each of those in depth.

Conventional Water Heater

We’ll start with the water heater that everyone is familiar with… the conventional tank water heater. A mainstay in just about every home in America.

How conventional water heaters work

These units work in a relatively simple to understand way. First, these units consist of a decent sized water tank that can provide enough hot water to last an hour. Cold water enters the container and is then heated by either heating coils or a natural element.


A conventional tank water heater has a few advantages. Namely, these units are the most economically friendly water heaters available on the market. This explains why they are the most commonly found water heater in America.

The other advantage that these water heaters have is that they last a long time. You can expect these to last 10-15 years, which is not as long as other systems. However, once the low price is accounted for the lifespan to price ratio is actually pretty decent.


The major drawback of these types of units is that they use a lot of energy. In fact, they are the most energy inefficient method of heating water. This is because they always heat water. Yes, these units even heat the water when you sleep and are at work.

Sure, you can turn off the water when you leave your house. However, you will have to wait an hour after turning it on to have enough hot water to do anything.

This leads into the next disadvantage. You get a limited amount of hot water at a time. Sure, this hot water might last for an hour. However, it will take another hour for the tank to refill. These types of systems are not ideal for households that have a high demand for hot water.

Final Verdict

It’s the status quo pick. If your budget allows it, then take a look at purchasing a tankless water heater. However, you can’t go wrong with a conventional water heater… for now.

Tankless Water Heater

bosch tankless diagram

Imagine a world where you can have infinite hot water in your home. Well, that day has come. The recent engineering breakthroughs in heater technology has made tankless water heaters much more affordable. Gone are the days where the only people that could afford a tankless water heater were the ultra-rich.

Average people can now afford these systems. Are they really that great though?

Let’s find out.

How tankless water heaters work

Tankless water heaters work with some kind of weird magic. Basically, these attach to the main hot water pipe. When water passes through these it passes through a bunch of different heating coils. These heating coils obviously heat the water.

Now, you can purchase an electric tankless water heater. You can also purchase a natural gas tankless water heater. They both work the same way. However, the natural gas water heater is much more efficient than an electric one. Using natural gas scares me though. I’m always afraid that it will leak and blow up my whole house.

ecosmart tankless heater

I’d just stick to the electric versions.


Well, the huge advantage with these is that you can get infinite hot water in your home. You can literally take a five hour long hot shower if you really want. Nothing is stopping you. Just remember that you have an electric bill and water bill to pay at the end of the month.

Along with that, you also get hot water on demand. Kind of like on-demand movies. If you want hot water, then turn on the hot water faucet and hot water will flow out. I guarantee it.

Another advantage that is not commonly discussed is how small these things are. You know much storage space a conventional water heater takes up?

A lot of space. You can do a lot of different things with all that storage space in your home. Honestly, the extra storage space is one of the best benefits of a tankless water heater… other than the infinite hot water.

Finally, these systems are much more energy efficient… in theory. Unfortunately, a common trend is that you will use more hot water now that you have unlimited hot water. This can somewhat negate the energy savings. Still, you use more hot water for the same amount of energy. That is what I call efficient.


There is one glowing disadvantage. Like a light in a cave, you can’t escape it. It’s always sitting there.

These units can lower your water pressure. Furthermore, they aren’t really designed for use as a whole house system. Their main use case is for a single faucet or two. A lot of these units do not have the water pressure requirements to make them effective for a shower.

Of course, you can purchase a whole house tankless water heater. Just make sure that it can provide the required gallons per minute that you want for a shower. Nothing is worse than taking a shower with low water pressure. Actually, taking a cold shower with low water pressure is probably worse than that.

Final Verdict

Slightly more expensive than a conventional water heater. If you live in a warmer state and have a bigger budget, then we highly recommend purchasing a tankless water heater. We did some reviews of the best tankless water heaters on the market.

Solar Powered Water Heater

A solar powered water heater is definitely one of the more uncommon water heaters available on the market. You won’t see this in many households. However, some people swear by their solar powered water heaters. Alas, they’re include in our list.

How Solar Powered Water Heaters Work

These heaters are powered by a renewable source of energy. The sun.

Now, these are not the units that rely on the sun heating a bucket of water. Of course, that will work, but it isn’t seen in America.

A solar powered water heater uses a solar collector to capture energy from sun rays and convert it to energy. This energy is then used to heat the water directly or heat a liquid that then circulates through piping in a storage tank. Fascinating stuff.


The first big advantage of these units is that they rely on the sun for energy. Infinite energy.

It’s also cheap energy. Actually, it’s free once the cost of the solar panel is paid.


These units have some big disadvantages. First, if you live somewhere that doesn’t get sun, then you’re out of luck. These don’t work well in a place like Seattle that does not get any sun.

Now, if you live in a place like Arizona or Florida where there is infinite sun, then these make perfect sense and work extremely well.

Even in sunny areas, you still want to have another water heater. If it’s nighttime or unusually cloudy, then you will not have hot water.

This is why most of these units have some sort of backup water heater included.

Finally, these systems are much more expensive than any other type of water heater.

Final Verdict

All in all, these get a big thumbs down from us. Only use a solar powered water heater if you want to save the environment. From an economic and practicality viewpoint, they just do not make any sense. Maybe in a few years when the technology improves.

Heat Pump Water Heater

This might be one of the most misunderstood water heaters on the list. The poor heat pump water heater. Don’t let the obscurity fool you. These make an excellent choice under the right circumstances.

How a Heat Pump Water Heater Works

A heat pump works by moving hot air from one location another location. Most homeowners with a heat pump use them to cool their homes. In fact, my home in South Florida has a heat pump. A heat pump can also be used to heat water.

Basically, a heat pump uses electricity to move heat from one location to another location. Just think of a refrigerator. Except in this case the heat pump brings heat into a contained area instead of expelling it.

This is different than a normal water heater that uses electricity to warm up heating coils, which then heats the water.

Heat pumps are actually much more efficient than a traditional electric water heater. This is because it is much easier to move heat than generate it.

Anyway, due to the fact that they move heat from one area to another. You should install them in an area that already has excessive heat. The weather in your area must not drop below 40 degrees. Heat pumps don’t work well in cold weather.

This makes them only viable in a handful of location in the United States.


Heat pump water heaters do have some big time advantages over traditional water heaters. For one, they’re much more efficient than a typical water heater. You will save money each month on your electric bill.

Next, they expel cold air. This means you can direct that cold air into your home during the summer. Not only will you save on your water heating costs; you will also save on your cooling costs.

That’s what I call a deal.


The big disadvantage with these is that they aren’t ideal for most places. This is because they just don’t work efficiently when the outside temperature drops below 40 degrees.

A minor disadvantage is that they cost more upfront. This is offset by the increased efficiency. Other disadvantages include more in-depth setup and more possibilities for things to break.

Final Verdict

Buy it if you’re in the proper climate zone and can afford the greater upfront cost.

Choosing the Right Sized Water Heater

man holding stiebel tankless heater

Once you have decided on the type of water heater you want, the next step is to choose the proper size. You don’t want to choose a unit that is too small and has the hot water run out during a shower. Ideally, you want a unit that has enough hot water to last you without ever running out.

This section of the guide will cover the best way to pick a heater size that works for you. We’ll break it down by the different types of heaters because each one has a different way to measure the amount of hot water produced.

Sizing a Conventional Water Heater and a Heat Pump Water Heater

Sizing one of these water heaters is not a particularly difficult task. You just have to understand how the words that are used in the water heating industry.

First, you want to look at the “first hour rating” of the water heater. This is simply the amount of hot water (measured in gallons) that it can supply in one hour. It will vary depending on what heating element it contains, the flow rate, and the cold water temperature.

Now that you have the first hour rating. You can compare that number to that amount of gallons used in your home per hour. Specifically, think about the maximum amount of water used per hour. This is also referred to as the “peak hour demand” in your user manual.

Determining peak hour demand is somewhat straightforward. Think of the hour that your household uses the most water. This is usually in the evening for most households, but sometimes it is in the morning.

Now, determine the hour that the most hot water is used. Usually, not always, this is when everyone takes a shower.

An average shower is about 10 gallons, shaving is about 2 gallons, food prep is 4 gallons, an automatic dishwasher is 6 gallons, and a washing machine is about 7 gallons.

Finally, estimate the amount of times you do the above tasks in an hour and all the gallons together. This will give you a good estimate of the gallons of hot water you use per hour.

You can use this number of hot water per hour to help determine the proper size for your water heater.

Sizing a Solar Water Heater

Sizing these systems is extremely simple in theory. It is much harder in practice though.

The most important part is to determine the amount of hot water used at any one time and purchase a water storage tank that can hold that amount of water. Most households with less than three people will use a 50 to 60 gallon tank. Under 6 people and an 80 gallon tank will work. More than six people and you will need a large tank.

The next step is to determine the amount of sun collection you will need. This is somewhat complex and your contractor will normally do this. However, a good estimate is approximately 1 square foot of collector space for every half gallon. Consult your solar technician before purchase though.

Once you have all that, you then need to determine the best positioning for the solar collector. As mentioned earlier, a contractor will have fancy software that will determine all of this stuff.

Sizing a Tankless Water Heater

Tankless water heaters measure heat in a slightly different method. Obviously, you don’t need to worry about the maximum amount of hot water you use per hour.

Instead, heat is measured by the temperature increase at a certain flow rate. This makes sense because the temperature decreases as the flow rate increases. Water has less time to pass through the heating coils and heat up.

Now, to determine the size of your water heater just measure the gallons per minute that you will use at any one time.

For instance, if you have want to use a sink that draws 1 gallon per minute and a shower that draws 4 gallons per minute, then you use 5 gallons of hot water per minute.

Determining the temperature is simple. Most people have their water temperature at 120 F. Measure the temperature of your tap water (70 degrees) and subtract that from 120. That is the amount of temperature increase you need.

In the example listed above you would need to find a tankless water heater that can increase the temperature by 50 degrees while maintaining a 5 gallon per minute flow rate.

Choosing a Circuit Breaker for Your Water Heater

Note: This is for a conventional water heater tank.

Disclaimer: Informational only. Consult an electrician. Getting this stuff wrong can burn your house down.

I’ll just save you the trouble of figuring out the exact match.

Get a 30 amp breaker and 10 gauge wire for your water heater. A 5500 watt heater (the maximum you will probably find) uses 23 amps at 240 volts (5500W / 240V = 23A).

This means you should use a 30 amp breaker. If you have less amps, then you can get away with a smaller breaker.

It runs cooler too, which will save you money.

On the off chance that your water heater pulls more than 23 amps, simply multiply the amperage by 1.25 to determine the minimum amperage of the breaker.

It will probably require a 40 amp breaker, which will use 8 gauge wire.


Maintaining a Water Heater

tools on a work bench

Fortunately, maintaining a water heater is a simple process. I’d wager that most homeowners do zero maintenance on their water heaters. No maintenance will generally last a 10 to 15 years. However, to get good life for your water heater you must do maintenance.

Don’t worry this maintenance is all relatively simple stuff and shouldn’t take more than an hour or so per year.

Draining the Tank

Yes. Draining the tank once every few months will help remove sediment piled on the bottom of the heater. Just turn off the cold water inflow. Open up the tank and drain it into a bucket.

Keep turning on the cold water inflow until no more sediment is in the water.

Remember to turn the water flowing into the heater on after you finish draining it.

Test the Pressure Relief Valve

Test this once per year. Simply release the pressure and make sure that it works.

Install a Water Softener

A water softener will reduce the hardness of the water. In other words, this will prevent the buildup of all that gross sediment on your appliances. This improves the life of them.

We did a roundup of some great water softeners for your home. Check it out.

Adjust the Temperature

Use it or lose it as the saying goes. Simply change the thermostat every year to make sure it stays intact. Every 10 degrees you lower it is an extra 5% in energy savings as well, which is nice.