On Demand Tankless Hot Water Heaters

Kevin Mathias Sep 29, 2018
Tap to Read ➤
Tankless water heaters not only give you hot water on demand but also save you a lot monetarily, when compared with the tank-type variety.
A tankless water heater is an on demand hot water heater which does not store hot water, but produces it instantaneously the moment you require it. It comes in a variety of models that use electricity, or gas (including propane and kerosene) to heat the water.
What a conventional tank water heater does is to heat the water and store it in the built-in tank. Over time this water begins to cool down triggering off the thermostat and heating the same water all over again. This leads to a waste of electricity, pushing up your power consumption and bills. The main advantage of a tankless one lies here.
It has got no storage tank. Until water does not flow through it, it is a dead unit. The moment you turn on the flow, it comes to life. The water triggers off a mechanism that turns on either the electricity or flow of gas which is ignited automatically.
This water runs through a series of specially designed tubes (mostly high grade copper) that heat it to very high temperatures instantly.
Water goes into the unit cold and in a matter of seconds begins flowing out hot. The capacity of a tankless one is measured by how many degrees it increases the temperature of water at a given flow. The standard measurement for this is gpm (gallons per minute).

Which Tankless Water Heater is Better

These heaters come in gas and electric models. Also these models are further divided into single-fixture units and whole-house units. Single-fixture units are those units that will be used only for one outlet. Whole-house units will be placed centrally and supply hot water to two or more outlets.
It is important to know what the exact use of the unit will be. If you require a unit for just one user at a time, and the users are few, a small capacity electric tankless water heater is a good choice. The only drawback is that it may use a lot of power since it has to heat the water quickly to the desired temperature.
If it will be centrally located and used by more than two outlets simultaneously, then a gas fired one will be a good choice. When going in for the whole-house model, make sure you know as to how many outlets will be connected to the unit.
And buy a unit which can handle the load when all the outlets are used simultaneously. If the model cannot handle the load, what everyone will get is barely warm or cold water.

Initial Costs

If you are thinking of savings on water heating in the long run, then you must get a tankless one. Maximum savings in the long run will come from the gas based versions. Whether you buy an electric or a gas based one, it is going to be much more expensive than the tank-type water heater.
Further, setting up the tankless ones is not very cumbersome as they are not as bulky as the tank-type variety. Problems that can occur with the electric version is in the wiring part. Even though these heaters will be on for a much shorter time than the tank-based heaters, the amount of current that they pull during this short duration is very high.
You may have to change the wiring in case the previous wiring is of lower capacity. This can be an additional cost which cannot be avoided since faulty wiring is not a good thing to have at home.
The gas based version will require venting. If the unit installed is in the bathroom, venting will be pretty simple; if it is a central unit with a bigger capacity, venting may be a bit complex and cost you more.
Whatever the initial costs of fitting a tankless water heater as compared to a tank-type one, it will be covered in a very short span of time. Once the initial cost is covered, it is super-savings throughout the life of the unit.


The prime reason many today are shifting from the tank to the tankless variety are the huge cost savings. Tankless ones can save you anything between 10% to over 40% in your total hot water bills. Some even go to the extent of claiming a saving of about 60%.
When you use a tank-type one, the water is heated and starts cooling down. In due time, this water is reheated. This uses electricity, increasing your power consumption.
When you use an electric tankless one, this heating and re-heating does not occur. The water is heated just once and used immediately. This is where you save. The savings here are not huge. Using one will usually save you approximately 10 to 20% in your power consumption.
The real saving is when you use the gas variations of tankless water heaters. Gas based ones (including propane and kerosene) can heat much larger volumes of water to a higher temperature instantly as compared to the electric ones. This is the reason gas based ones are recommended for the whole-house units.
Larger models will be able to handle even 3 to 4 simultaneous connections. For an electric model to cope up, it will have to guzzle down a huge amount of electricity, skyrocketing your electricity bills. Using the gas based version will save you an approximate 40% over the conventional electric tank-type version.
The life of a tank-type version is approximately 10 to 15 years, and that of a tankless version is up to 20 years. The reason for this is that tankless ones do not store water; hence the chances of corrosion and deposits are minimal. This too leads to a big saving in the long run.
The life of a tank-type version is approximately 10 to 15 years, and that of a tankless version is 15 to 20 years. The reason for this is that tankless ones do not store water; hence the chances of corrosion and deposits are minimal. This too leads to a big saving in the long run.


The main use of all water heaters are in the bathroom and used mostly for bathing (shower and bathtub). In places with colder temperatures hot water is also used in the lavatory, kitchen sink, and laundry.
If you are planning to connect all of these to your water heater, then you must go in for a gas fired model which has got the capacity to heat water for all these requirements simultaneously.
The model you buy will also depend on what temperature of water normally flows out of the faucet. Places having a colder temperature will require heaters with higher heating capacity to heat the same amount of water as in a hotter climate.
When choosing the tankless water heater for your home, you must make sure that you know exactly what you will require it for. Getting one fitted, and then realizing that you will require a model with more or less capacity will be a big waste of your money.
You should know as to how many outlets are to be connected to the unit. You must also know the temperature of water that normally flows out of your faucets during the coldest time in the year. All the tankless ones have got an adjustment for the output water temperature.
So, if you are in doubt go in for a higher capacity model, you can always reduce the temperature of water required. Never go in for a lower capacity model if you are in doubt. You will be able to reduce the output water temperature, not increase it when there are multiple users.
Cost savings using a tankless water heater (more so the gas-fired variety) over the tank-type variety are very significant over the years. Get one installed in your home today, and begin counting your savings for a long time to come.