Appliances that Heat Water for Different Purposes
Heating or boiling water is a basic cooking skill (some admit that it is their only cooking skill), but in the plumbing trade there are two types of appliances that heat water: water heaters and boilers.
What’s the difference?
Basically, the difference is why you would want heated water to shower with, but not boiling; and why you could power something with boiling water, but not warm water.
Water heaters and boilers both heat water, but for different purposes.
This handy guide dives into:
- What a water heater does
- What a boiler does
- The key difference between a water heater and a boiler
- How Benjamin Franklin Plumbing Bay Area can help you make the right decisions about the water heater or boiler that is best for you
What a water heater does
A water heater is designed to warm the water supplied to your kitchen, bath and other appliance outlets. While we take for granted hot water flowing out of our showerheads and sinks, this convenience does come at a cost. Indeed, water heating is your second largest household expense (the second is your HVAC system, in case you were wondering).
There are different fuel sources for water heaters, gas, electric, hybrid and even solar. Which is better for your home depends to some extent on what your local utility provides (and if it doesn’t, if your budget accommodates the added cost of a propane tank or a solar array), and the type of water heater.
There are two types of water heaters: tanked and tankless.
Tank Water Heaters
A tank water heater warms cold water incoming from your water service utility employing either a gas burner or electric heating rods inside of the tank. Tanks come in various sizes depending on how many appliances and family members reside in the home.
Once water reaches a desired temperature, it remains in the tank until you turn on the hot water in your sink, shower, dishwasher or clothes washer. That warmed water moves through your plumbing system to the open faucet. Meanwhile, cold water replenishes the water that is called upon by the open faucet, and again is heated until the desired temperature is reached.
If the water in the tank is used faster than water is replaced and heated, you have the problem of getting an unexpected cold shower. This is why it is important to properly size the tank to accommodate multiple family members and/or appliances drawing hot water at the same time.
Average life span of a tanked water heater is 10 to 15 years. To ensure longevity, it is recommended to clean out the tanked water heater once a year or so. There’s a water valve at the bottom of the tank. Turn off the electric breaker or the pilot knob for the heater, connect a hose to the valve, then open the valve and drain water into a bucket. This eliminates any sediment at the bottom of the tank that could lead to corrosion. When the tank is drained, close the valve and turn power back on.
Tankless Water Heater
A big advantage of a tankless water heater is that it heats the water going into your shower or sink for as long as you run the water. An additional advantage is tankless water heaters are more energy efficient. You could save up to 30 percent on your average heating costs because water is warmed only as you need it, unlike a heater that warms water stored in a tank whenever it goes unused and the temperature drops. Plus, tankless water heaters typically use less water, so there is an additional savings to your water bill. And if you have limited space, tankless water heaters take up a lot less room.
Some tankless water heaters provide hot water instantly, but not all do. The models with instant water contain a recirculation pump. If instant hot water is important to you, make sure the tankless water heater you select includes a recirculation pump.
Nothing is free, however, and tankless water heaters generally cost more than tanked water heaters. Over time, however, energy and water utility savings more than recover the upfront charges.
Another potential drawback is tankless water heaters are best suited for small homes, apartments and condominiums. For large homes, tank water heaters are the best application. However, if you experience regular cold showers because your tanked water heater is overtaxed, you could add a tankless water heater dedicated to dishwashing and clothes washing appliances. That could lighten the load for your tanked water heater and provide hot showers even when multiple family members are using the facilities at the same time.
A tankless water heater has a typical lifespan of 20 to 30 years. You can ensure a long working life if you perform regular maintenance. Because there are various electronic and moving parts, consult a professional technician to perform maintenance. Regular maintenance intervals are every four to five years. If you have hard water, however, perform maintenance yearly. If you install a water softener, you can extend the maintenance period to the normal four to five years.
What a boiler does
Regardless of whether a water heater is tanked or tankless, both perform the basic function of heating water to a desired temperature for washing and showering. A boiler also heats water, but the process is very different.
A boiler does more than just simply heat water; it actually boils the water and then turns it into steam pumped into radiators, fan coils or radiant heat. Not only is steam an inexpensive way to transport heat, it is more energy efficient than air transport.
Boilers are made from steel, cast iron or stainless steel. The most energy efficient of the three is stainless steel.
Fuel options are gas, oil or electricity. Some boilers use alternative fuel sources such as wood pellets, but these aren’t common. Generally speaking, gas is preferable and most common. Gas boilers are usually the least expensive to install and operate. If gas is not available from the utility, oil and electric boilers are your other options, but each has their own drawbacks.
Oil boilers require a storage tank and regular deliveries to maintain fuel on hand. In addition, oil is a more expensive fuel source compared to gas. However, certain models of oil boilers are more energy efficient than gas.
Electric boilers are most often the choice over oil, if only because the fuel source is readily available. On the other hand, electric boilers are typically more expensive to operate than oil boilers and in many cases are not as energy efficient.
To make the best informed decision to select a boiler system’s fuel type, consult a professional plumber.
In any event, boilers in general are energy efficient because they work as a closed loop system. What that means is after heat is pulled from the steam, that steam is turned back into water. This warm water remains in the pipes and can be heated again, but the heating process is even quicker since it’s already warm.
Boiler steam has multiple applications, including:
- Power central heating systems
- Heat floors home floor radiant systems
- Clean carpets
- Heat water for cooking and washing
The primary purpose of a boiler, however, is home heating. To add other applications, such as what you need a water heater for, requires additional components and more space. And, of course, additional installation costs and maintenance expenses.
Boiler vs water heater: the basic differences
The chart below provides a quick summary of the differences between a water heater and a boiler.
|Stores, heats and supplies water||Turns water into steam to generate heat|
|Ideal for small spaces||Can heat an entire tub, pool or complex|
|Simple controls||Complex pumps and controls|
|Runs on electricity, gas, hybrid or solar||Runs on electricity, natural gas or propane, heating oil or alternative fuels, e.g., wood pellets|
|10 to 15 year lifespan||20 to 30 year lifespan|
Call Your Friendly Plumber
For most homeowners, Installing a hot water heater is not a DIY project; it most certainly is not for a boiler system. Even before installing either kind of system, a professional plumber can help you best decide on the system that fits your needs and your budget.