no energy is wasted and therefore no need to exhaust it. You may ask who makes the best Tankless WH and the answer would have Noritz at the top of the list as the largest tankless WH manufacture in the world.
Since tankless WH has no storage tank it comes in a small package, roughly 5 times smaller than the tank WH. It can be mounted on a wall outside of the house and free up valuable space in the garage or in some cases turn that look alike pantry where the tank WH was into a real pantry inside the house.
No Energy wasted with Tankless Water Heater
The tankless WH doesn't use energy when there is no need for hot water and has no standby heat loss. The showers can now be truly endless and no worry for the next person wanting to take a shower. The typical shower uses 2.5 gallons of water per minute and a mid size tankless WH can supply roughly 6 to 7 gallons of hot water per minute. Now here 2 persons can take shower simultaneously or at the same time and still have enough hot water for the washing machine or the kitchen sink. Today's Tankless water heaters with best tankless technology are very sophisticated computer controlled appliances. They control and keep the water temperature to preset level regardless of water volume and pressure.
In other words the water temperature at the shower head is the same regardless of how much water is being used, a second shower is turned on or third user draws hot water. The gas burner or electric heater modulates the energy, gas or electric to the desired level to achieve the set temperature. All this is possible with modern electronics and having a closed loop circuit with high accuracy. The leading manufacturer of tankless water heaters are Noritz, Takagi, Rinnai and Bosch. Noritz Tankless Water Heaters are among the best on the market. They all have refined their products for extreme reliability and durability. Typical tankless WH lasts 3 times as long as a storage tank WH with no noticeable degradation in performance or efficiency over time. Tankless WH models like Noritz 751 or Takagi TK-3 can supply an entire house with continuous hot water and save energy and money.
Tankless Water Heaters are Safe
None of the safety issues of tank WH applies to tankless water heaters. Their burners come on only when hot water is needed, they don't have a permanent pilot. The gas burner is electronically ignited and if installed outside it constantly monitors the outside temperature and activates its anti freeze circuitry preventing a pipe freeze when needed. Its electronics also monitors incoming water pressure, flow and regulates outgoing hot water pressure and flow. The highly efficient burner and heat exchanger achieve high efficiency and save energy. Incoming gas volume and pressure is also monitored and in case of a malfunction the unit shuts itself off and provides diagnostic information. Takagi TK 3 is closely related to Noritz 751 and is also able to supply an entire house with hot water.
Another saving aspect of tankless hot WH is that since you never run out of hot water there is no need to mix the hot water with cold water and therefore the water temperature can be set lower. For example the tank water heater is typically set to 160 to 180 degree F even though the water temperature used for shower is roughly 105 degree F. This is done to not use so much of the hot water in the storage tank and make the hot water last longer by mixing it with cold water at point of use. With tankless water heater there is no need for this, there is endless hot water and therefore the temperature can be set to 110 degree F and there is no need to mix in as much cold water. That saves energy too because the water is not heated to the higher temperature. Any time cold water is mixed to the hot water that reduces the efficiency indirectly. Tankless water heaters are green products and help reduce the carbon footprint.
Government incentives make Tankless WH more affordable than ever before
Thanks to government subsidies, tax credits, tax rebates and sometimes additional local utility rebates tankless water heaters can compete favorably with the old fashion Storage tank water heaters. Their initial cost has come down and the payback on energy savings can be very substantial. According to various statistics 30% to 40% of the energy cost of a typical home is consumed by the water heater. Tankless water heaters can reduce that by more than 50%. Tankless water heaters are also popular for commercial and industrial applications. Models like Noritz 751, Noritz 842 and Noritz 931 can be installed in series to provide almost boiling water. Restaurants, Hair Salons, Gyms and many other commercial businesses can benefit from the energy savings of tankless water heaters in addition to the space savings. Smaller units like Noritz 631 are well suited for smaller applications, like apartments or smaller homes.
Most units allow you to set the desired temperature via a control panel that can be conveniently installed in the bathroom or any other place. This gives you immediate control of setting the desired water temperature. There may be times that there is a need for higher temperature of 180 degree F for example, this is easy to set through the digital control panel. This is very useful when filling a SPA or filling a large bath tub. Tankless water heaters are also well suited for vacation homes. Electric Tankless Water Heaters are also highly efficient and can be easily installed where there is enough electrical power. In most areas electricity tends to be expensive compared to natural gas and a natural gas or liquid propane or LP tankless WH may be more economical. Today's units are among the most compact tankless water heaters ever built and carry the energy star classification.
Correct Installation makes the difference
Because tankless water heaters are sophisticated appliances the more critical is their correct installation. They should be installed by licensed, factory certified and experienced professionals. By far the most installed type of tankless WH is the one powered by natural gas. Electric models are not very economical because of mostly higher electric rates and potentially higher installation cost. Electric tankless water heaters usually have a high electric power demand and may need supply circuits of 100 A or more amperes. This would require an upgrade to the existing electric system of the house that can be costly. Smaller electric tankless water heaters can be easily used in point of use locations, for example for the kitchen sink. They require much less power and are very useful.
The most important factor is the location where the tankless WH is going to be installed. It is crucial to be close to the gas meter and the gas line to be properly sized so it is able to supply the volume of gas needed. Utility gas meters can also be restrictive and not able to supply enough gas. This is usually not a problem, most utility companies can exchange the meter to a larger unit free of charge. Since the tankless WH modulates its burners it adjusts the gas flow to the burner for desired temperature.
Problems usually occur when the unit needs to supply greater amount of hot water and is not able to receive enough gas volume for the burners. The gas supply and volume is very important to have a trouble free operation. It is not that tankless water heaters use more gas; they use more of it when heating the water instantaneously versus the tank WH that slowly heats the water. The energy it takes to heat water to a certain temperature is the same. It is important how efficiently that energy is used. A professional installation also tries to minimize the pipe length from the tankless WH to the next bathroom. This reduces the amount of cold water that is flushed before the hot water reaches the faucet.
There are some pump products on the market that continuously circulate hot water in the pipes so that hot water is immediately available when you open the hot water faucet. These pumps are very wasteful of energy because in most homes the hot water pipes are not insulated and made of copper. Copper is a very good heat conductor so all the hot water in the pipes are constantly radiating heat to the surrounding and cooling off quickly. It works sort of like the radiator or the heater in a car. Hot water is pumped through it to cool. These pumps and the associated valves use the cold water pipes for the circulation of water, so the cold water in the pipes become warm as well.