Tankless Water Heaters 101

Tankless Water Heaters 101
January 17, 2013 Lorelie
Tankless Water Heaters

Tankless water heaters are the latest types of water heaters that are gaining popularity

These water heater models have basically gotten rid of the storage tank for storing hot water and instead heats water instantaneously when hot water is on-demand.  Tankless water heating units are very cost effective.  Since they do not heat water unless it is needed, they do not suffer from standby heat loss like storage tank water heaters do.  In addition, tankless water heaters have a very small form factor when compared to traditional storage tank water heaters.  This means they occupy less space in the home, freeing valuable space which used to be reserved for the storage tank.

One of the best things that make others switch to tankless water heaters is that these water heating units are able to provide unlimited amounts of hot water and they can provide this at a rate of 2-5 gallons per minute.  This means they are not only suitable for small apartments and condominiums, but they can also be used for large homes.  In fact, tankless water heaters can either act as your main source of hot water, or it can be used in addition to your storage tank water heater, providing you with the hot water you need even during the winter seasons.

Since traditional water heaters are mostly intended to supply main hot water fixtures inside the home i.e., showers, dish washers, clothes washers, and sinks, the other fixtures of the home, particularly remote bathrooms, pool showers, and outdoor sinks do not have any hot water supply.  On the other hand, with a tankles water heater, you can install point-of-use tankless water heaters on these locations so you can have hot water whenever you need it.

With traditional storage tank water heaters, the water kept and maintained hot inside the tank until it is ready to be used.  This is not the case with tankless water heaters.  Due to this, you save a lot of money because water is not being heated unnecessarily without being used.  On a whole year, this savings can translate into tens to hundreds of dollars saved on utility bills.

According to some studies, if a home uses 40 gallons or less of hot water per day, a household can save nearly up to 25% more energy if they were to use tankless water heaters instead of traditional storage tank types.  In fact, even if a household consumes up to 90 gallons of hot water per day, they can still save up to 10% more energy.  This just shows how energy efficient tankless water heaters are.

There are basically two types of tankless water heaters in terms of fuel type – electric and gas-fired.  How you choose yours can depend on your location or your intended use.

Electric Tankless Water Heaters – these are perhaps the easiest to install of the two because you do not need to worry about installing any addition venting system.  However, if you will be using this type of tankless unit, make sure your home can accommodate the amp draw demand of these units.

Gas-fired Tankless Water Heaters – when installing these types, make sure the gas line that you have in your home can accommodate the gas requirement of your water heating unit.  It is also important to properly install its venting system so that no carbon monoxide fumes escapes inside the home and that all fumes are properly vented outside.  If you are not confident with you DIY skills with this one, it is highly advised to have a professional do it for you.

There are two types of tankless water heaters in terms of size – point-of-use and whole house.  The type you choose will basically depend upon your hot water needs.  Point-of-use tankless water heaters are installed near the fixtures it will supply hot water with.  Since they are very small, they can be installed under the kitchen sink or the wall in the bathroom.  However, their small size means they can only serve one fixture.  Almost all point-of-use tankless water heaters are powered by electricity. Whole house tankless water heaters on the other hand can supply hot water for the whole home.  If the unit has a high GPM, it can accommodate simultaneous usage.  However, should the demand be too great, a side-by-side whole house tankless water heater configuration is advised.

If you are keen on getting a tankless water heating unit for your home, it is important that you determine how many taps will be open during peak usage.  This will give you a rough estimate on how much GPM or flow rate you will need with your unit.   Another factor that you may want to consider would be the temperature of the water that enters or feeds your water heating unit.  This means that if the water entering the unit is much colder, the performance decreases as the unit will be generating lower amounts of hot water.  This does not mean you cannot use a tankless type in your area, it simply means that you will need a unit with a higher GPM.

Say you require that the water temperature in your shower reaches 90°F and the ground water temperature in your area is 65°F.  Subtracting 65 from 90 will give you 25.  This means that 25°F is amount of temperature rise that you will need in order to arrive at your required temperature.  When you have this rate of increase, you will be able to determine the amount of GPM needed for your home.

To measure flow rate, collect water from your faucet for 10 seconds.  Measure the volume of water in gallons and multiply it by 6 to give you a total of 60 seconds or 1 minute.  The volume you will arrive at is the flow rate you have in gallons per minute.

If you household only has a small consumption during peak usage, then a whole house electric unit would suffice.  However, if the demand is much greater, a whole house gas-fired tankless unit may be able to meet the tough demands.  Otherwise, you will have to go with two whole house units working side-by-side.

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