Tank vs. Tankless Water Heaters

admin Plumbing March 16, 2016

Tank vs. Tankless Water Heaters

When it is time to replace that old hot water tank you have many choices in today’s market. Simply shopping for a hot water tank can be daunting but throw in the tankless water heaters and it becomes an ocean of information, statistics and data. To help bring it all into perspective we will talk about some base comparisons here.

Pros and Cons for Both Systems
PRO – Endless Hot Water!! Nobody likes running out of hot water in the middle of a shower and, if you have teenagers, you have probably had this happen on more than one occasion. The tankless water heater will happily pump out hours of hot water for your enjoyment without breaking a sweat.
CON – Deep pockets required!! While your tankless will keep that water coming it gets expensive after a while. A tankless can run upwards of 200,000 BTU and once it fires up it keeps burning at the relative rate until you turn that tap off. Comparitively, your typical hot water tank will run approximately 50,000 BTU and only runs until the stored water in the tank has reached temperature.

Don’t take this first pro/con as bad. When put into perspective the average household usually uses hot water for a couple of hours per day including showers, dishes, laundry etc. The tankless will only run during that time while the tank will reheat the standing water over and over again through the 24 hour period. What you need to deterime from this is what your daily usage is to help you make your decision.

PRO – Instant Hot Water!! No more waiting for the water to make its way through the pipes to my faucet.
CON – Sorry, this is a myth. Yes the tankless is quick to get the water to you it still has to fire up and heat that water then send it through the pipes to the faucet. Essentially the tankless is actually slower than your conventional hot water system. In a hot water tank the water is already pre-heated and waiting to head down the pipes to you. The tankless has a sensor built in that determines when water begins to flow. This tells the brain of the system to fire up the BTU’s and heat the water. It can often take 5 to 10 extra seconds to get the hot water where you want it.

A little tip… Ensure all hot water piping that can be accessed has insulation around it. This helps to keep the water hot while stored in the pipes. Once the pipes get cold they will absorb heat from the water once it starts to flow again through energy transfer which will keep the water from reaching peak temperature at the faucet for some extra time.

PRO – More space to work with. A tankless system takes up very little space when compared to a tank and the tankless hangs on the wall.
CON – Cold water sandwich. Here’s the scenario. Your spouse just gets out of the shower. You quickly turn the water back on and it is so nice and hot. Unfortunately, when the water was turned off and then back on the computer in the tankless system turned off the flow of energy. While you are enjoying that hot water for the first few moments there is about a gallon of cold water heading your way and will last several seconds when it hits the shower head.

The best solution for this sandwich is a storage tank. Yes, it seems redundant to have a storage tank when you are getting a tankless heater but it does solve the problem by storing a small amount of hot water to ensure that your heat is distributed quickly. These tanks typically run between 2 and 20 gallons depending on your needs. It goes without saying that installing a larger storage tank means you really haven’t saved any space.

PRO – Clean water. Because the tankless does not store any water it flows cleaner as it does not pick up any contaminates that would be found in a storage tank.
CON – The tankless requires more maintenance. Although it does not store water it still has water flowing through it and in hard water areas there can be considerable calcium buildup. Manufacturers recommend servicing about once per year.

A final note is the cost of installation. Typically you can have a 50 gallon hot water tank installed for about $1200 (includes installation, taxes etc.). A tankless can run about $2000 all in. There is more cost up front so you have to weigh efficiencies against usage.
The costs noted above can vary depending on models, sizes, retailer etc

The list can go on and on. An endless supply of fact vs fiction is out there but the items that are important to you are
1. Can the system keep up with my requirements?
2. What is our hot water usage overall as a family?
3. Is there a return on the investment (either through efficiencies or in dollars)?
4. Do we want to make a large investment up front?