When you're building a new home or replacing an old unit, one decision you're going to face is whether to go tankless or traditional. Chances are you're used to traditional water heaters, which hold a large volume of water inside a tank and constantly work to keep it hot. Tankless water heaters warm up water on demand without the use of a tank. Choosing between the two types can be difficult, but at Benjamin Franklin Plumbing®, we can help you figure out which is best for your home, as well as install and maintain your new water heater.
What Are Traditional Tank Water Heaters?
Tank water heaters come in a variety of sizes that indicate what volume of hot water they can hold. Smaller tanks, like ones with 20- or 30-gallon capacities, work best for homes with fewer occupants and less overall water use. From there, the capacity goes up, with most residential water heaters hitting a max of 80 gallons. Tank units heat water in one of two ways: they either use fuel (most often gas, like in your kitchen) or electricity. That said, most modern gas heaters do use electricity to ignite their pilot lights. From there, gas units disperse the heat through the water via a heat exchanger. In fully electric units, there's a heating element, like you'd see on an electric stove. This element allows electricity to release its heat energy and warm up the water. Either way, traditional water heaters pull in cold water from the bottom and then heat it, which leaves the warmer water up top for your home's use. They also contain an anode rod that attracts minerals from your water to prevent them from corroding the components. Tank water heaters hold the full volume of the tank unless you're actively using that water. They will continually refill themselves with water. They also hold the water in the tank at the temperature you set so it's ready for use, sending it out as necessary when you turn on hot water somewhere in your home. Generally speaking, you'll also find insulation around the tank to help slow down heat transfer, reducing how much energy the unit needs to use to keep the water warm. You can usually access the thermostat that controls the water temperature by opening a panel on the front of the unit.
What Are Tankless Water Heaters?
Tankless heaters are just as their name describes: water heaters that do not use tanks for storage. You might see these also called "on-demand heaters," as they only heat water when you turn on your faucet. Like tank units, they rely on either gas or electricity to do so. Where tank water heaters have a large tank you need to make space for, tankless ones generally mount onto walls or beneath faucets. When you turn on a hot water tap in your home, water flows into the heater. There, either an electric heating element or a gas burner heats a component called a heat exchanger, which then transfers heat to the water flowing through the tankless heater. Tankless units heat up quickly and to high temperatures, instantly heating whatever water flows through them before distributing it throughout your plumbing. While they heat water on demand, you may still experience a short delay as the heated water travels to your faucet.
How to Choose
Each type of water heater has its pros and cons, so it's not as simple as telling you which to choose. Instead, you need to weigh the pros and cons of each against your needs.
Traditional Water Heater Pros
- Limited only by size of tank
- Easier to install
- May continue working during a power outage if using a standing pilot ignition
- High flow rate
Traditional Water Heater Cons
- Leaks
- Potential water damage
- Slow to regenerate hot water
- Higher utility costs
Traditional tank water heaters are common because they generally have lower up-front costs than tankless ones. Because they're so common, tank water heaters tend to be more accessible, too. The amount of water they can put out is high, so they're only limited by the size of the tank. That might come into play if you have particularly limited storage space, but you can often move a size up to resolve hot water supply issues. Plus, gas units may still function in emergencies like power outages — especially if they have a standing pilot light. Once they reach that water limit, though, it can take a long time for the tank to both refill and fully reheat. Because the tanks are so large and need to preserve the water temperature throughout the day, they tend to result in higher utility bills. Most importantly, the tank can leak. Every plumbing component can, but with such a big volume of water in the tank, damage can be widespread if you don't catch it early.
Tankless Water Heater Pros
- Energy efficiency
- Heats water quickly (though not always instantly at the tap)
- Continuous hot water — within flow rate limits
- Less chance of water damage
- Space-saving design
- Less prone to large leaks
Tankless Water Heater Cons
- Limited by flow rate
- More expensive up front
- Requires electricity to operate (no hot water during power outages)
- Requires regular descaling in areas with hard water
Tankless water heaters are a newer technology, making them less common. That means you'll need to find plumbers who know tankless heaters well, like our team at Benjamin Franklin Plumbing®. Since they heat water on demand instead of using energy to keep a large volume of water hot, tankless heaters are less likely to increase your utility bills. The only thing that limits them is the amount of water they can allow through and heat up. That is, while you have near-unlimited use of hot water if the tank is full in a traditional heater, too much use at once can make a tankless heater struggle. If your home routinely sees people starting the washing machine, running a bath, and taking a separate shower at the same time, you may need to install more than one tankless unit to keep up with demand. Installation tends to be more up-front due to being less common, though you can often offset those prices with your utility savings over time. Even if they use gas, every tankless unit also utilizes electricity, which means you won't have hot water should your power go out.
Which Is Best?
Ultimately, it's going to depend on your needs. The immediate availability of a tank unit is tried and true. The large tanks mean you'll usually have some form of hot water available. However, if you tend to run out of hot water quickly or want to focus on your utility bills, tankless could be the choice. Because the choice between traditional and tankless water heaters is so individual, you'll need someone on your side. With our trained, expert plumbers at your service and a Forbes Best of 2024 award backing us up, you'll know we can handle anything from leaks or a new water heater to faucet repairs and more. Choose Benjamin Franklin Plumbing® for all your plumbing needs in San Marcos!
