Tankless Water Heater vs Tank – Which Should You Choose?
Reading Time: 7minutes
When it’s time to replace your water heater, one of the biggest decisions you’ll face is choosing between a tankless water heater vs tank. Both types provide hot water, but they operate differently and come with unique benefits and drawbacks.
A tank water heater stores and preheats a set amount of water (usually 40 or 50 gallons), ensuring it’s always available but with a limited supply. A tankless water heater, on the other hand, heats water only when needed, offering an endless supply but at a higher upfront cost.
So, which one is right for your home? In this guide, we’ll break down the differences, pros and cons, installation requirements, maintenance needs, and key factors to help you make the best choice.
How Does a Tankless Water Heater vs Tank Work?
Tank Water Heater:
A tank water heater is a large tank of water that a gas burner or electrical elements work around the clock to keep hot. hThe water is always hot and ready to use, but once the tank runs out, you’ll have to wait for it to refill and reheat. These systems run on gas or electricity and require sufficient space (and access to air) in a utility room, basement, garage or attic.
Tankless Water Heater:
A tankless water heater heats water on demand. Instead of storing hot water, it quickly heats water as it flows through the unit. Because there’s no tank to empty, users never run out of hot water. Without needing to keep 40 or 50 gallons of water hot all day and night, tankless water heaters are much more energy-efficient than their tank counterparts.
Since a tankless water heater heats water as you use it, it’s important to have the right size and model tankless installed. To be sure you have a tankless that’ll keep up with what you need, be sure to have a certified plumber who has knowledge and experience specifically with tankless water heaters. We often come behind handymen or even plumbers without tankless training to fix tankless issues.
🔗 If you’re into the details, you’re speaking our love language. We love to talk plumbing. Learn more about how a tankless water heater works.
A Tankless Water Heater vs Tank: The Three Questions to Answer
When comparing a tankless water heater vs tank, think about:
Cost
Hot Water Needs
Lifespan
You’ll need to decide on the investment you’d like to make at installation versus the energy savings earned over time. Also think about the hot water needs of your family: Do you need to time your showers so that everyone has hot water? Enjoy filling up a garden tub? Finally, think about how long you plan to stay in your current home, as some homeowners appreciate the appeal a tankless can have for potential buyers.
The Pros and Cons of Tank Water Heaters
Tank Water Heater Advantages
Lower upfront cost – more affordable than tankless models. Simpler installation – works with existing plumbing and power sources. (this also affects cost) Works well for homes where hot water isn’t in high demand
A tank water heater is a budget-friendly choice with a straightforward installation process, so long as the home already has a tank water heater. Replacing what is already in a home can be ideal for homeowners looking for a simple solution. If your household doesn’t use a large amount of hot water at once, a tank water heater may be a good fit.
Tank Water Heater Disadvantages
Limited hot water supply – once the tank is empty, you must wait for it to refill. Higher energy costs – constant heating leads to standby heat loss. Age Concerns – Reduced performance and flood risk with age Takes up more space – requires a dedicated area in your home.
Tank water heaters have some significant downsides. Since they store a set amount of water, you might run out of hot water during back-to-back showers or high-usage periods. Additionally, because the unit continuously reheats water even when it’s not in use, your energy bills could be higher.
As tank water heaters age, sediment can build up at the bottom. This sediment makes it harder for the heat source (the heating element or burner) to reach and heat the water inside of the tank. You may find, with time, that you run out of hot water faster and it doesn’t get as hot. Additionally, as a water heater ages, the possibility of it leaking increases significantly. A burst or even just leaking tank water heater can flood a home fast.
Pros and Cons of A Tankless Water Heater vs Tank
Tankless Water Heater Advantages
Endless hot water supply – perfect for large families. More energy-efficient – only heats water when needed. Compact design – frees up valuable space. Longer lifespan – can last 20+ years vs. 10–15 years for a tank heater.
If you never want to run out of hot water again, a tankless water heater is an excellent option. It heats water on demand, ensuring you always have enough for back-to-back showers, dishwashing, and laundry—making it an ideal solution for large families. This type of system is also more energy-efficient and lasts longer than a tank water heater, making it a great long-term investment.
Tankless Water Heater Disadvantages
Higher initial cost – installation is more expensive than traditional models. May require plumbing or gas line upgrades – especially in older homes. Flow rate limitations – may need multiple units for large homes with simultaneous usage.
Despite the benefits, tankless water heaters do have some downsides. In a tankless water heater vs tank comparison, the upfront cost of the tankless is higher, and some homes may require additional plumbing modifications to accommodate the system. Additionally, while a tankless can provide endless hot water, the flow rate can be a concern—if multiple showers and appliances run simultaneously, a single tankless water heater may struggle to keep up. Tankless water heaters are sophisticated pieces of technology, so if you find yourself in need of tankless water heater service, we highly recommend a certified tankless specialist.
Key Factors to Consider When Choosing Between A Tankless Water Heater vs Tank
Hot Water Demand: Large families benefit from a tankless water heater because it provides endless hot water. A tank water heater may run out of hot water during back-to-back showers or high-usage periods.
Budget: A tank water heater is more affordable upfront, while a tankless water heater saves money long-term on energy bills.
Available Space: Tankless water heaters are wall-mounted and ideal for small homes. Tank water heaters require more space.
Energy Efficiency: A tankless water heater eliminates standby heat loss, reducing utility costs.
Lifespan & Maintenance: There can be a big difference between the lifespan of a tankless water heater vs tank. A tank water heater lasts 8–15 years, while a tankless water heater can last 20+ years.
Installation and Maintenance Considerations
Tank Water Heaters:
Installation is generally simpler and faster, especially if replacing an existing unit.
Requires annual flushing to remove sediment buildup.
If the anode rod isn’t maintained, the tank can corrode and leak.
Tankless Water Heaters:
Installation is more complex and may require gas line or electrical upgrades.
Requires descaling to prevent mineral buildup, especially in areas with hard water.
More durable, lasting over 20 years with proper maintenance.
Tankless Water Heater vs Tank: How a Future Home Sale Can Affect Your Decision
If you’re planning to sell your home in the near future, your choice of water heater can make a difference to potential buyers. A tankless water heater vs tank water heater might appeal to different buyers: tankless models are often seen as an upgrade, offering endless hot water and modern efficiency—something today’s buyers expect in many higher-end homes.
On the other hand, if your goal is simply to show that the water heater won’t need replacement anytime soon, a new tank water heater could be your best choice. Oftentimes, if a water heater is aging, home inspectors will recommend replacement. This can become a negotiation point (and even a point of friction) during a home sale.
Whether You Go Tankless or Tank, Make Sure It’s Professional Grade
The water heaters available to consumers, rather than licensed plumbing companies, are not professional grade. Yes, you can buy a tankless water heater on Amazon. Yes, you can buy a tank water heater from the big box stores. But in both cases, you shouldn’t. At minimum, you should know that you are purchasing a much lower quality product. When you’re deciding between a tankless water heater vs tank, make sure both of your options are professional grade units.
First, be sure you’re purchasing a reputable brand, as finding the parts or a technician able to service an off brand tankless from Amazon will be difficult. Second, even the brand name water heaters, like AO Smith, that are available to purchase by consumers, are not the professional grade water heaters that plumbers purchase at a supply house. Plumbers have special access to professional grade water heaters that can’t be purchased in the big box stores.
Water heaters involve gas and venting of dangerous gasses or electricity. We’ve seen hundreds of dangerous examples where an unqualified person installed a water heater to save money. To get a high quality product that’ll last and be safe, have a reputable plumber install a professional grade tank or tankless water heater. We recommend Navien or Rinnai tankless water heaters or AO Smith Professional Grade water heaters.
Try Our Tankless Water Heater vs Tank Quiz
If you’re still weighing a tankless water heater vs tank, our Water Heater Buying Guide can help make things clearer. With interactive questions, it walks you through costs, installation details, energy efficiency, space requirements, and how long each type typically lasts. With a few simple answers, you can feel confident understanding why a tankless or tank is best for you.
At Aaron Services: Plumbing, Heating, Cooling, we specialize in tankless and tank water heater installations. We’re happy to help you find the perfect option for your home. Whether you’re looking for an energy-efficient upgrade or need a reliable system that meets your family’s hot water needs, our experts are here to help.
