Either a tank or a tankless water heater can be a good option depending on your budget and your hot water needs. There are advantages and drawbacks to each type of unit so what is the better option for one home may not be the best for another. The best way to determine which type of water heater will be the better choice for your specific situation is to look at them side by side to see how they compare in terms of price, energy efficiency, and all of the other important factors.

Energy Efficiency

A tankless water heater will almost always be more energy efficient and cost less to operate than a tank unit. Modern tank water heaters are still fairly energy efficient. The issue is that they use energy even if you’re not home and haven’t used any hot water that day. Although the tank is insulated, the water inside it will still slowly cool down over time. As a result, the unit will need to turn on every few hours so that the water in the tank always stays as hot as it should. This isn’t an issue when you’re home and doing laundry or otherwise actively using hot water, but it does add up to quite a bit of energy waste overall.

Tankless water heaters are completely different since they heat on demand instead of constantly having to keep the water hot. This means that the unit always stays shut off and never uses any energy until you turn on your shower or otherwise call for hot water. When hot water is needed, the unit will then start heating and bring the water up to the set temperature within a few seconds. It takes a tankless unit much less time to heat the water since it heats the water as it flows through the unit instead of having to heat a much larger volume at one time like a tank unit.

On average, a tankless water heater will use anywhere from around 10 to 40% less energy. The reason that this number varies so much is that it depends almost entirely on the home’s hot water needs, i.e. how many total gallons you typically use in a day or month. Homes that normally use no more than 40 gallons of hot water per day will see much greater energy savings compared to if your normal daily hot water usage is 80 gallons or more. If you frequently use more than 100 gallons a day, the difference in energy usage between the two types of units will typically be minimal.

Upfront Cost

Cost is one area where tank water heaters have an advantage. On average, a tank unit will cost at least a few hundred dollars less than a tankless unit. Electric tank water heaters are the least expensive of all your options, but it’s a trade-off as they also will cost more than any other unit to operate.

Not only do tankless water heaters have a higher purchase price, but they also tend to cost a bit more to install. Exactly how much more the installation cost will be depends partly on whether you’re just replacing an existing tankless unit or switching from a tank water heater. Switching from a tank to a tankless unit will increase the total cost as the existing plumbing will need to be retrofitted or adapted to accommodate the tankless unit.

Space Requirements

Another advantage of tankless water heaters is that they are extremely compact and take up very little space. Tankless units are mounted or hung directly on the wall so this type of unit can really go anywhere in the home. Most units are even small enough that you can mount them inside your shower, above your bathtub, or in some cases even underneath the kitchen sink. The small size makes tankless water heaters a great choice for apartments, small houses, mobile homes, or any other place where space is at a premium.

Life Expectancy

Life expectancy is another factor where tankless water heaters generally reign supreme. Tank water heaters have an average lifespan of eight to 12 years. Electric tank units usually last longer than gas units, but will still typically last for maybe 15 years at the very most. One reason why tank units don’t last as long is that they tend to experience more wear and tear due to them needing to run and reheat frequently. Another reason is that the water slowly causes the tank to rust and corrode so that it will eventually start leaking. Sediment also collects inside the tank and will make the unit less effective and force it to work harder if it isn’t flushed regularly to remove all of the sediment.

The typical lifespan of a tankless water heater is around 20 years, but well-maintained units can sometimes last for 30 years or more. This longer life expectancy often makes a tankless unit the better and cheaper long-term option since you won’t have to replace your water heater nearly as often. Another thing to consider is that tankless units are much less prone to leaking since they don’t store water and thus don’t have the same issues with rust, corrosion, and sediment build-up.

Lag and Recovery Times

Lag time refers to how long it takes before the hot water actually starts flowing out of your shower or other fixture, while recovery time is how long it takes for the unit to fully heat cold water up to the correct temperature. Recovery time is only a factor with tank units and only comes into play when you use lots of hot water in a shorter period and fully deplete the stored supply of hot water. Any time you use up all of the stored hot water, you’ll usually have to wait for 30 minutes to two hours before the water is again as hot as it should be. The recovery time for gas tank units tends to be quite a bit shorter as electric units heat more slowly.

Recovery time isn’t something you’ll ever need to worry about with a tankless water heater. A tankless unit can theoretically provide a limitless supply of hot water, meaning you’d never run out no matter how long you left the shower or faucet running. However, tankless units are limited in terms of how much hot water they can provide at one time. If you try to use more gallons of hot water per minute than what the unit is rated for, the temperature will fluctuate.

The biggest issue with tankless water heaters is that they typically have a longer lag time. With a tank unit, the water flowing from the fixture will usually be fully hot within only a few seconds. The lag time increases a bit in winter when your pipes are colder, but this is true with any type of water heater. The lag time for a tankless unit is typically at least 15 to 20 seconds. If the fixture is a long distance from the water heater and the water has to travel much further through your pipes, the lag time could be more than a minute or two.

At AJ Danboise Plumbing, Heating, Cooling & Electrical, we have nearly 100 years of experience providing professional plumbing services, and we’re the number one choice for water heater installation in Farmington Hills and throughout the Detroit Metro area. We install and repair tankless and tank units, and our team can explain the differences and help you decide which is best. For more information on your water heater options or if you need any other plumbing, heating, air conditioning, or electrical services, give us a call today.

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