Water Heaters vs. Boilers: What’s the Difference?
It’s all about the hot water
Highlights
Boilers, also called furnaces, provide central heat and often hot water to your home.
Water heaters only provide hot water to your fixtures.
Boilers are more costly to install and repair.
There are more options for water heaters.
It’s easy to take hot water for granted, but let’s face it—we need it. There’s only so long you can go without a hot shower, after all. Plus, the dishwasher depends on it, and a bubble bath just isn’t the same without warm water.
Both boilers and water heaters supply your home with all the hot water you need, but they’re also very different. If you need to choose between the two, consider these points to decide on what would work best for you.
The Main Difference Between Water Heaters and Boilers
There are a handful of big differences between water heaters and boilers that are important to factor into your decision-making.
Water Heater
Water heaters are powered by gas or electricity rather than steam or radiant heat. They won’t provide central heat to your home like their competitor, but that may be right for you if you live in a warm climate year-round. Here are some other unique characteristics of water heaters.
Electric or gas-powered
Water produced is safe to consume
Doesn’t heat water to boiling
Doesn’t provide central heating
Inexpensive materials and installation
Boiler
Unlike water heaters, boilers don’t just heat your water—they also heat your home. While installing a new boiler is roughly twice as expensive as the alternative, they have longer lifespans, which means you could save on replacements in the long run. Here are a few other important distinctions to keep in mind.
Steam or radiant heat-powered
Provides central heating in addition to hot water
Water is non-potable
Heats water to near boiling
Costly installation and materials
What Is a Boiler?
Boilers provide central heating for your home and hot water to your faucets (talk about two birds with one stone!). Although they can be a bigger investment upfront, they can save you money in the long run. Also remember that a boiler is different from a furnace, despite the term being used interchangeably.
Uses for Boilers
A boiler is used to produce steam or hot water. Some other core functions of boilers include:
Central heating
Boiler-based power generation
Cooking
Sanitation
Boilers are suitable for residential, commercial, and industrial use. Many homes use a boiler for heating because they are more energy-efficient than a traditional furnace. Boilers are also quieter than a furnace.
Types of Boilers
The two main types of boilers are hot water boilers and steam boilers. Hot water boilers are used to produce hot water for residential and commercial properties. Meanwhile, steam boilers generate steam and are more frequently used in industrial settings.
Boilers also vary in the amount of pressure they use. Low-pressure boilers produce up to but not more than 15 pounds per square inch (PSI), which equates to roughly 250 degrees F, while high-pressure boilers can reach levels of up to 100 PSI. For residential purposes, low-pressure boilers are almost always favored.
The cost of your boiler varies according to the size of your home. A new boiler for a standard 1,500 sq. ft. home costs about $5,700 on average.
Boiler Pros
Heat is evenly distributed
Less noisy than water heaters
No vents or forced air that blows allergens and dust
Typically lasts longer than water heaters
Costs less to run than forced-air systems
Boiler Cons
Costs two to three times more than water heaters
Replacement parts are more costly
Takes time for temperature to change after adjusting thermostat
Requires additional ductwork for central cooling system
What Is a Water Heater?
Water heaters have one mission: to provide your house with hot water. It’s definitely one of the first must-have appliances you’ll want to install in a new home.
Uses for Water Heaters
As the name indicates, water heaters heat up water. The water is then used for a variety of purposes, including cleaning, showering, and cooking. A water heater receives cold water from the supply line, heats the water using gas or electricity, and then pumps hot water through whichever outlet you open.
Types of Water Heaters
There are two primary ways to categorize water heaters: by heating source or by type. Gas water heaters are one of the most common and often seen in older homes. Newer homes may have an electric water heater or even a solar one.
A storage water heater, also known as a conventional water heater, comes with a water tank and stores hot water inside. Storage water heaters cost from $600 to $800, and installation can cost anywhere from $900 to $2,500.
Meanwhile, a tankless water heater, also known as an instantaneous water heater, heats water upon demand. Most tankless water heaters are powered by gas because electric models require a high amperage most homes may not be able to provide. Tankless water heaters cost $2,523 on average, and the actual price can vary from $1,329 to $3,717.
Pros
Less energy to run than boilers
Smaller in size (tankless)
Easier to install
Many different options
Lower upfront costs
Less expensive to replace
Cons
Requires separate system for central heating
Higher utility bills
Tankless may require water softener
Water temperature can be inconsistent
Boiler vs. Water Heater
Boilers and water heaters are significantly different, but how can you choose? If you already have a central heating system, then you’re probably better off installing a water heater. However, if you’re building your house from the ground up, you might benefit from choosing a boiler system.
Options
Standard boilers are designed for heating, but can also run a heating loop through a tank to heat your domestic water efficiently. Combination boilers will perform heating and domestic hot water without the use of a storage tank.
The main two types of water heaters are tank or tankless. The tank heaters heat the water and hold it in the tank until it’s needed. On the other hand, tankless heaters heat water on demand. They can also use a heat pump or a hybrid heater, which uses 60% less electricity because it uses heat in the air and the ground instead of electricity. If you’re keen on keeping energy costs down, deciding between a water heater with a heat pump and a boiler may be the way to go.
Most choices: Water heaters
Life Span
Boilers can last 25 years or more, while combination boilers last about 10 to 15 years. Eventually, you’ll notice problems like odd noises, radiators taking a long time to heat, water leaks, or higher gas bills. High-quality boilers that are properly maintained have the best chance of lasting a long time.
Water heaters usually last around six to 10 years, with most carrying a six-year warranty. Notably, if you consider the pros and cons of tankless water heaters, you’ll find that tankless models can last 20 years with a 15-year warranty. Common signs of a failing heater include water leaks, hissing sounds, and inconsistent performance.
Longest life span: Boilers, if you invest in a high-quality model
Price
Installing a new boiler costs $5,800 on average. A standard-efficiency boiler costs $3,000 to $6,000 and a high-efficiency boiler costs $6,000 to $11,000. Installation costs $1,000 to $2,500 on average, but some installs can reach $5,000.
Replacing a standard gas boiler costs $4,000, and replacing a high-efficiency boiler costs $7,500. These costs include a tank inspection, soil test, tank replacement, old tank disposal, and environmental cleanup.
Additionally, if your boiler is powered by oil, you’ll need to account for periodic oil refilling. 50 gallons of oil could last all winter if your home is less than 1,000 square feet, with 100 gallons costing around $300 to $600. Note that this estimate will fluctuate as global oil prices change.
On the other hand, water heaters cost substantially less. A new water heater costs $1,200 on average with installation. Tankless heaters cost $1,000 to $3,000 while high-efficiency heaters cost $700 to $3,000, and installation ranges from $150 to $1,500.
Most affordable: Water heaters, if you already have a central heat system
Installation
Installing a boiler in your home requires extensive work, especially if you’re putting in a brand-new system. Boilers are very heavy and have many complex parts. You would need to install the boiler, radiator, and the input and output pipes under flooring. For a job like this, it’s probably best to call a boiler installation company near you.
If you have some plumbing knowledge, you may be able to DIY a water heater installation. However, there are many steps involved, and you’ll need some muscle to get it done.
Easiest to install: Water heaters
Repair/DIY-ability
Generally speaking, if you’re noticing issues with your boiler, like leaks, temperature differences, or emissions problems, you’ll want to call an HVAC professional. Boiler parts are intricate and complex, so repairing them is not a typical DIY project and isn’t recommended if you don’t have the proper certification. Instead, find out who to hire to fix a boiler and reach out to them directly.
If you call in a pro, you can expect the cost of a boiler repair to fall somewhere between $240 and $2,500.
Water heaters are easier for DIY repairs, depending on the problem. Most DIYers will be able to troubleshoot common issues like temperature being too hot or cold, the pilot light going out, or the heater working less efficiently.
If you have to hire a pro, the cost of a water heater repair ranges from $100 to $1,300.
Easiest to DIY repairs: Water heaters
Maintenance
Boiler maintenance requires an annual inspection of your boiler, vents, and wiring. Every six months, you should lubricate the circulating pumps, flush, and clean your boiler. Additionally, conduct a safety valve check monthly, and perform
To maintain your water heater, you should conduct a visual inspection for leaks, test the water valve, and drain the tank to remove sediments.
Easiest to maintain: Water heaters
Sustainability
Boilers can be considered more sustainable because they harness the natural properties of hot water or steam.
But if you’re looking for something that is 100% sustainable, your only option is a solar water heater. These cost around $1,000 to $6,000 for the tank and $2,000 to $4,000 for installation. Although the upfront costs are high, it’s hard to beat having unlimited hot water without paying for electricity or natural gas.
Additionally, you can opt for high-efficiency tankless water heaters that use less energy.
Most sustainable: Boilers
Water Heater vs. Boiler Installation Cost
Installing a brand-new boiler costs an average of $5,800 for all the labor and materials involved, though you could pay up to $11,000 or more if you opt for a high-efficiency boiler. By contrast, it costs an average of $1,200 to purchase a new water heater and have it installed, and $3,000 is the most you’ll pay for both tankless and high-efficiency options.
DIY vs. Hiring a Pro
For new boiler installations, hiring a boiler installer near you is always recommended because of the risks involved. On the flip side, you may be able to install a water heater on your own if you have prior plumbing experience. However, hooking up your machine to either your gas or electricity line can be hazardous, so outsource this job to a pro if you have even the slightest doubt.
Frequently Asked Questions
Boilers are used mainly for central heating, and water heaters are used for ordinary household water use. In fact, a conventional boiler works best if your home already has a water heater system in place. Sometimes a boiler can be combined with indirect water heaters. But there are also premade combination boiler heaters.
No. Boilers and water heaters are not interchangeable because they serve different purposes. A water heater will never be able to supply warm water or steam for your central heating system. In most homes, a boiler and a water heater may be combined to provide heating and daily use of hot water. Other homes may opt for a furnace over a boiler for their heating needs.
Yes. Boilers need water to run without overheating, also known as dry firing. If you run it without a sufficient volume of water, either because of a burst pipe or a leak, you run the risk of damaging your machine or jeopardizing the safety of your home as a whole. When in doubt, shut off your boiler and repair any plumbing issues before turning it back on. Alternatively, consider installing a low-water cutoff (LWCO) before any issues arise. This gadget will protect your boiler by monitoring water levels and automatically shutting it off if it gets too low.