How to Choose a Water Heater: Your Guide to Different Types of Water Heaters
Did you know that nine million water heaters get sold in the US every year? Or, that Energy Star units only make up about five percent of these sales? Nevertheless, water heating represents a key area for energy savings.
Energy efficiency represents just one of many factors you’ll need to consider if you’re in the market for a new heater, though. After all, there are five types of water heaters that you should be familiar with, including tankless and gas water heaters.
With this in mind, we’ve crafted this comprehensive guide to help you select the right heater for your home needs. Keep reading for a full breakdown of how water heaters work, how to maintain them, and when it’s time to replace them.
What Is a Water Heater?
Water heaters are familiar fixtures in the vast majority of homes. They usually look like tall utilitarian metal drums and are kept out of the way in basements or laundry rooms. That said, some of the newest models provide on-demand water, hence no need for a tank. Despite these advances, old, reliable water heaters remain the most widely used in the US. Among their many advantages is sheer simplicity.
After all, an old-fashioned water heater is fundamentally a drum filled with water and a heating mechanism on the inside or bottom. Despite their minimalism, they remain a truly impressive appliance. Why? For one, they exploit the heat rising principle to bring hot water to your faucet. As it turns out, there’s a lot more hiding beneath the wooly insulating blanket than you may realize.
Components inside Water Heaters
To better understand how water heaters function, let’s take a look at their components. Water heater parts include:
- Dip tube
- Shut-off valve
- Heat-out pipe
- Heating mechanism
- Drain valve
- Sacrificial anode rod
Let’s take a closer look at each of these parts and how they contribute to a water heater’s functionality. We’ll start with the easiest piece to identify, the tank.
The Water Heater Tank
A water heater’s inner shell is comprised of a heavy metal tank with a water-protective liner that can hold 40 to 60 gallons of hot water at 50 to 100 pounds per square inch (PSI). You’ll notice that the outside of the tank is covered in an insulating material. For example, polyurethane foam gets applied. Over this insulating material, there’s an additional insulating blanket or decorative outer shell.
The Dip Tube and the Shut-off Valve
At the top of the water heater, you’ll find the dip tube. Water enters the tank via this tube and travels to the bottom where it gets heated. What about the shut-off valve? It sits outside and above the unit. This valve shuts off water flow into the heater.
The Heat-Out Pipe and Thermostat(s)
At the top of the tank’s interior, you’ll see the heat-out pipe suspended. This pipe allows hot water to exit the unit. A water heater thermostat is both a thermometer and a temperature-control device. Some units have a separate thermostat for each element.
Inside the tank, electric water heaters have heating elements to warm the water that flows in. Gas water heaters employ a burner and chimney system. An electric water heater employs an electric heating mechanism.
The Drain Valve
Near the bottom of the exterior housing, you’ll find the drain valve. This feature makes it a cinch to empty the tank to replace elements. It’s also handy when removing sediment or transporting the tank to a new location.
The Pressure Relieve Valve and Sacrificial Anode Rod
The pressure relief valve is a safety device that ensures the water heater’s pressure stays within safe limits. Last but not least, the sacrificial anode rod sits suspended in the water heater tank. Made of aluminum or magnesium with a steel core, it retards water corrosion.
How Water Heaters Work
Within a water tank, the thermostat controls the temperature of the water. Most heaters come with the option of setting the temperature to a range between 120 and 180 degrees Fahrenheit. Manufacturers recommend keeping the temperature at 120 to 140 degrees Fahrenheit.
This ideal temperature range is hot enough to be efficient for household functionality, yet won’t pose a scalding threat. Bear in mind that if you’ve got small children in your household, stick to the bottom of this range. What’s more, keeping your water heater thermostat set at a lower temperature proves most energy efficient. What’s more, when you remember to decrease the thermostat when you leave for vacation, you can enjoy even greater savings.
Where is this thermostat located? Underneath the protective cover plate. There, you’ll see it has a dial or knob you can turn to set the temperature. When cold water feeds into the dip tube from your home’s water lines, it flows to the bottom of the tank, where the heating mechanism heats it to the temperature you’ve indicated on the thermostat.
As this water heats, it rises to the top of the tank. This heated water exits the tank via the heat-out pipe located near the top of the tank. As you can see, the water heater design proves basic but highly efficient and effective. Learn more about water heaters and red flags that require the immediate consultation of a plumber.
5 Different Types of Water Heaters
Now that you understand the basic principles associated with water heating, let’s take a closer look at the five main types of water heaters. They include:
- Conventional storage tank water heaters
- Tankless water heaters (a.k.a. on-demand water heaters)
- Heat pump water heater (hybrid water heater)
- Solar-powered water heater
- Condensing water heater
How do you choose the right water heater for you? That’s an excellent question that involves exploring the pros and cons of each unit type. Let’s start with an examination of tank versus tankless water heaters.
The Difference Between Tank and Tankless Water Heaters and Their Benefits
You’re likely most familiar with a conventional storage tank water heater. Why? Because it remains among the most popular units on the market. That said, more homeowners are opting for tankless systems and with good reason. Here’s a breakdown of the pros and cons of tank versus tankless water heater systems. From price tag to maintenance, the comparison below will help you decide which one’s right for your home.
Conventional Storage Tank Water Heaters
This water heater type has a tank that holds water to be heated. In other words, the tank’s capacity limits how much hot water you have available to you at one time. Think long showers that end in cold surprises. The water heater tank is insulated so that when water heats up, it stays that way until needed.
Tanks have two valves, the temperature control valve and the pressure control valve. When the water reaches a temperature of more than 120 degrees Fahrenheit, the temperature control valve opens. As for the pressure release valve? It opens to decrease pressure buildup at 150 psi or higher.
Conventional Water Heater Maintenance
While these are generally no-fuss tanks, you’ll need to clean them out at least two times per year. During this cleaning, you’ll need to remove any mineral scale or sediment build up. This precautionary step will also reduce the chances of corrosion occurring.
Why does this unit type remain so popular despite water quantity constraints? Because it’s affordable and easy to install. It’ll last you, on average, 12 years. Especially when you enlist experienced professionals to keep it in tiptop shape.
Tankless Water Heaters
Tankless water heaters (a.k.a. on-demand water heaters) offer a nearly endless supply of hot water. Relying on modern technology, they require no tanks. Instead, super-heated coils fill with water, heating it in a matter of seconds. In other words, it’s a heat-as-you-go system. It’s a great setup, but you must ensure you get the right size for your household.
For example, a small tankless water heater won’t keep up with your family’s water usage. The result? The production of lukewarm or cold water. You’ll also need to keep in mind that these units do well in homes with natural gas to power their water heater. But larger models will necessitate a bigger gas line and more gas for proper functioning.
The same goes for tankless water heaters that rely on electricity. If you’ve got a larger tank, you’ll likely need to ramp up your house’s electricity capacity.
Tankless Water Heater Maintenance
It’s easy to assume that tankless water heaters don’t require maintenance, but that’s not the whole story. Even though they don’t have tanks, you’ll still need to clean your water heater annually to remove mineral scaling and prevent corrosion. Unlike standard units, you may find cleaning tankless water heaters to be more difficult. Why? Because parts are smaller and more challenging to reach.
Tankless water heaters require a larger investment upfront as their cost is significantly higher than a standard model. Remember, too, that adjustments to your electrical utilities or gas lines may prove necessary. How long do tankless water heaters typically last? About eight to ten years.
Now that we’ve dug more deeply into the differences between tank and tankless water heaters, here are a few more options for your consideration.
Heat Pump Water Heaters
Heat pump water heaters (a.k.a. hybrid water heaters) help you economize on your electricity bills. How? These units don’t directly generate heat. Instead, they rely on heat in the air and in the ground to warm water. Electricity moves this heat from the air or ground to the water. As a result, such units often utilize 60 percent less electricity than traditional water heaters.
That said, they house the pump on top. As a result, they require extra room, sometimes upwards of eight feet of vertical clearance.
Heat Pump Water Heater Maintenance
Because this water heater utilizes heat from the ground or air, it won’t function well in cold spaces like basements. It’s also not suitable for frigid climates. It proves among the most expensive water heater types to purchase.
Like the other water heaters on this list, clean it regularly (once or twice a year) to prolong its lifespan. Among its chief benefits remains a significant reduction in utility bills.
Solar Powered Water Heaters
As the name suggests, solar-powered water heaters rely on thermal rays from the sun to heat water. They’re a great idea if you already have solar panels on your house or are considering installing them.
Relying on roof-mounted solar panels to harvest heat, solar water heaters may be the most energy-efficient units of all. The energy collected by solar panels gets transferred to a closed-loop system that relies on a heat-conductive material.
These units work well in climates where most days are sunny. That said, such systems also require backup plans utilizing natural gas or electricity on rainy days or when the sky gets overcast.
Solar Powered Water Heater Maintenance
Solar powered water heaters have tanks, so you’ll need to clean them twice a year to reduce mineral buildup, sediment collection, and corrosion. You’ll also need to keep up on solar panel maintenance.
While these units prove quite energy-efficient, it could take upwards of 40 years to see a return on your investment due to the costliness of each unit.
Condensing Water Heaters
Condensing water heaters rely on your home’s unused gas fumes to heat water. They remain the best option if your family uses primarily natural gas as its energy source.
How do they work? They funnel heated exhaust from the natural gas system to raise water temperatures. Like solar powered water heaters, they store the heated water in a tank.
Condensing Water Heaters Maintenance
Like the other heaters on this list, you’ll need to clean this tank at least once a year. This unit may also require the cleaning of gas import valves annually.
This type of water heater is not available in smaller models like 50 gal storage tanks. It works best for families with a capacity of more than 55 gallons. What’s more, if your home doesn’t run on natural gas, this unit won’t work for you.
The Difference Between Residential and Commercial Water Heaters
What about the differences between residential and commercial water heaters? Two distinctions can be made based on:
- Size of the storage tanks
- Gas input levels (for gas-fired heaters)
When it comes to storage tank sizes, residential water heater tanks top out at 100 gallons. As for commercial units? They may hold upwards of 250 gallons.
That said, for small enterprises, residential heaters may work just fine. There are also situations where a commercial water heater may be used in a residential setting to heat water and provide heat for a living space. As for gas input for gas-fired heaters? Residential heaters can handle up to 75,000 British thermal units (BTUs), whereas commercial units intake one million BTUs.
Signs You Should Service or Replace Your Current Water Heater
How do you know when it’s time to service or replace your current water heater? From gas heaters to solar powered ones, red flags include:
- The age of your system
- Loss of hot water volume
- Rising heating bills
- Reddish discoloration in the water
- Too many repairs
If you’re dealing with the factors listed above, schedule a water heater maintenance appointment. Not sure where to find the right water heater, maintenance expert? Contact us to discuss your plumbing needs.