The Benefits of a Tankless Water Heater
Tankless water heaters — also called instant or on-demand units — offer cost savings, endless hot water, and a smaller footprint. Here's why they're a smart investment for most homeowners.
On-Demand Hot Water — Only When You Need It
Unlike the traditional water heaters, which have a tank, a tankless water heater does not use energy to maintain the hot water supply. In fact, these units only expend energy when a hot water tap is turned on or when certain appliances — like the washing machine or dishwasher — are being used.
This style of on-demand operation helps to provide the biggest benefits: cost and energy savings. Along with savings, a tankless unit will provide an ongoing supply of hot water while not taking up much space.
Long-Term Cost & Energy Savings
8% to 50% More Efficient Than Tank-Style UnitsThe biggest benefit of a tankless unit is that they are energy efficient and can help homeowners save money long-term. The traditional tank-style units will use energy all the time to keep the temperature in a tank that is typically 40 to 50 gallons in size.
However, a tankless unit provides hot water on-demand. There is no continual heating of stored water. When water is heated just when needed, a tankless unit will not have issues related to standby heat loss — this is when heat escapes from the tank, and the water inside has to be reheated time and time again.
💡 Department of Energy
According to the Department of Energy, a tankless unit can be between 8% and 50% more efficient than traditional tank-style units. The actual energy savings a homeowner sees depends on the amount of water used and the unit's efficiency.
Endless Supply of Hot Water
Never Run Out — Even After a 10-Hour ShowerWhen everyone needs a shower, anyone who is not first or second may be limited to using cold water if a traditional tank-style unit is still in place. However, with a tankless unit, this scenario will never occur.
Because a tankless unit works by heating the water from the external source when it is demanded, a person could shower for 10 hours (or more), and the water would be just as hot as it was for a 10-minute shower.
Understanding Flow Rate
A Key Factor in Tankless PerformanceEvery tankless unit is designed with a set maximum flow rate. What this means is that just a specific amount of water will be heated at a time. If someone has five separate showers turned on simultaneously, most tankless units will not be able to keep up with the demand.
However, if the water usage stays beneath this flow rate, the unit can supply all the hot water needed — indefinitely.
One or Two Showers
Well within flow rate — endless hot water with no issues at all.
Multiple Simultaneous
May exceed flow rate. Your plumber can size the right unit for your household.
Requires Less Space
Wall-Mounted & CompactIf someone has a small home, they may want to avoid taking up a lot of room with the water heater. Unfortunately, tank-style systems are quite large. This is not the case with a tankless unit.
Usually, a tankless unit will be mounted on the wall. This means it will take up much less space compared to the alternative. While each unit varies in size, the average tankless unit is around 10 inches deep, 18 inches wide, and 27 inches tall — much smaller than the traditional tank-based system.
Tankless Size
~10" deep × 18" wide × 27" tall. Mounts on a wall and fits in most closets.
Tank-Style Size
Requires dedicated floor space in a basement or utility closet. Much larger footprint.
Reduced Likelihood of Leaks & Damage
No Tank = No Tank Leaks, Flooding, or MoldWith tank-style units, the possibility of a leak is high. As time passes, minerals from hard water will begin to accumulate in the tank. This causes corrosion, which eventually results in leaks.
Since there is no tank on a tankless unit, there is no possibility of a tank leak, flooding, water damage, mold, or other related problems.
- Tank corrosion from mineral and hard water buildup over time
- Tank leaks that can cause water damage to floors, walls, and belongings
- Flooding risk from a catastrophic tank failure
- Mold growth caused by slow, undetected leaks around the tank
Reduced Risk of a Tank Explosion
No Tank Means No Pressure Buildup RiskThe modern plumbing code requires that all water heaters with a tank have a pressure relief and temperature valve to open and release the pressure. The purpose of this is to make sure the tank does not explode.
As time passes, sediment and minerals from the water can begin to clog this valve, which means it may not be able to function properly. If this occurs, and too much pressure builds up, it puts the tank and everyone in the home at risk.
⚠️ Tank Explosions Are Rare But Serious
While the situation is rare, an explosion is serious and can cause damage, injuries, and death. It is a good idea for those with a tank-style unit to test the pressure relief valve annually to ensure it is functioning properly. With a tankless unit, this is a non-issue because there is no tank to explode. This is just one less thing to worry about.
Tank vs. Tankless: Side-by-Side
| Feature | Tank-Style | Tankless ★ |
|---|---|---|
| Energy Use | Continuous — heats 24/7 | On-demand only |
| Hot Water Supply | Limited by tank size | Endless (within flow rate) |
| Size / Footprint | Large — requires floor space | ~10"×18"×27" — wall-mounted |
| Leak / Flood Risk | High — corrosion over time | Virtually none |
| Explosion Risk | Possible if valve fails | Non-existent |
| Standby Heat Loss | Yes — constant reheating | None |
| Efficiency vs. Tank | Baseline | 8–50% more efficient |
Tankless Benefits — At a Glance
Ready to Go Tankless?
LaVergne's Plumbing & Heating can help you choose the right tankless water heater for your home, size it for your household's flow rate, and install it professionally. Contact us today to learn more about making the switch.