What to do when it takes too long to get hot water from a water heater to the kitchen or bathroom sink.
In response to frequently asked questions and comments that it takes too long for hot water to reach the shower or a sink, explore the recommended solutions below.
One solution is recommended when buying a new tankless water heater, and it includes selecting the model with the built-in recirculation feature. The recommended models are reviewed below.
The other solution applies to the tank-type models and requires installing the hot water booster or a circulation pump with the recirculation line.
The slow hot water delivery problem could be avoided if the installation was correctly planned, resulting in fewer headaches, complaints, water and energy waste, and higher bills.
The adequately installed water heater is vital for a long-term and unobstructed operation and hot water delivery. A water heater should be installed with a piping system that is as short as possible and near the fixtures that use hot water; in the bathrooms, kitchen, laundry, garage, and wherever hot water is needed.
If there is a distant sink that requires a long pipe run = slow hot water delivery, install a point-of-use water heater (POU), such as an Eemax, Tempra or Tronic tankless or Ariston as the small tank-type appliance.
If the distance between the heater and a fixture is long, it will take some time before hot water is delivered because the cold water is already stored in the pipes between the source and the fixture and needs to be pushed out.
The shorter the distance is, the faster the cold water will be removed from the pipes, and the faster you will get hot water, no matter if it is a tankless or tank-type water heater. It is also recommended to insulate all the water lines, especially if it runs through the rooms with the lower temperature.
So, when it comes to buying a water heater, do not rely on marketing terms "instantaneous." Instant or, to be more accurate, almost instant is possible with the provided solutions below; recirculation and hot water boosters.
If looking to buy a tankless water heater with a built-in recirculation system, choose the Navien NPE-A or Rinnai RUR series.
The Navien NPE-A series offers three models for different home sizes: NPE-180A, NPE-210A, and NPE-240A all heating potable water with up to 199,900 BTU gas input and water flow up to 11.2 GPM (35F temp. rise). This is sufficient for large homes with up to 4 bathrooms. These specs come from the largest model, NPE-240A, but if you need less power/water flow, choose one of the two smaller models.
All the models are equipped with an internal circulation pump, but an external pump can also be added to the water heating system and for recirculation applications, but it should be sized appropriately to provide the right water flow. The circulation pump is what speeds up the hot water delivery.
This ultra-high efficient series of tankless water heaters can achieve a high energy factor of 0.95 providing high savings to the users due to the low gas emission burner and environment-friendly operation.
One of the greatest features found on Navien NPE-A models, which makes them different from other models or brands, is the ComfortFlow technology. The ComfortFlow technology can minimize the water temperature fluctuation within the system, resulting in more pleasant showers and hot water delivered when needed. This is possible because the system recognizes the usage pattern while saving water and time when using the recirculation mode.
Only the NPE-A models can provide two pre-heating modes; internal and external recirculation mode. The recirculation mode is selected by changing the position of the DIP switch (it is OFF by default) and positioning the 2-way valve. As can be seen below, it is easy to switch between two modes.
Internal recirculation mode
Set the 2-way valve to "INT." position
Set the DIP switch to 1-ON, 2-OFF
External recirculation mode
Set the 2-way valve to "EXT." position
Set the DIP switch to 1-OFF, 2-ON
No matter which mode is chosen, you will have hot water delivered fast with the less "cold-water-sandwich" and with no minimum water flow rate required.
Even if there is a need for more hot water and in any situation, the cascading capability allows up to 16 units to be linked into one system.
Also, for the perfect work, all these features are controlled from one main command center found on the unit's front panel. The advanced electronics allow users easy control, monitoring, and troubleshooting with the given error codes from the diagnostics system.
Also, maintenance is essential.
For example, an inlet water filter located inside the cold-water inlet must be cleaned periodically to maintain the proper water flow. Any obstructions inside the filter will result in reduced flow and slow water delivery.
Rinnai tankless RUR water heaters are, as the above Navien, on-demand units that produce hot water in endless supply and thanks to the advanced electronics, with the consistent temperature where the cold-water-sandwiching is almost eliminated.
The powerful and Eco-friendly gas burner can produce a maximum power of 199,000 BTU and deliver up to 9.8 GPM of hot water to multiple fixtures and high demanding applications, resulting in superb efficiency and ultra-low NOx gas emission.
The RUR models can also be remotely monitored and controlled with smartphones, providing great energy and money savings, comfort, and convenience.
What makes Rinnai RUR series a good pick for faster hot water delivery is its compliance with the ThermaCirc360 - water heating recirculation technology, so even if there is no dedicated return line, hot water is delivered fast.
Instantaneous or almost instantaneous hot water delivery results in reduced time and energy waste. ThermaCirc360 recirculation technology utilizes the bypass technology, internal pump, Circ-Logic recirculation technology, 24-hr digital controller, and thermal bypass valve.
Recirculation technology is what ensures faster hot water delivery throughout the home, reducing the wait time for hot water and improving convenience and comfort. It also reduces energy consumption and greenhouse emission.
If you are the owner of the electric or gas tank-type water heater and hot water reaches the shower or the tap slowly and insufficiently, or you are running out of hot water fast, a solution is to install a water heater booster. A small point-of-use water heater can be used as a booster, such as the one from Rheem RTEX series.
According to the manufacturers, boosters can increase hot water delivery by close to 50%, also improve performance and comfort - if installed per instructions. So, per Rheem, if you own a 30-gallon short unit with the booster, it delivers hot water as the 40-gal medium unit, or if you own a 50-gal tall model, it becomes as the 80-gal unit – meaning more capacity is available to you.
This small electric unit has only a few pounds, making it easy to install directly to any tank or a nearby wall.
You can also buy a water heater mixing valve that works as the tank booster, where the higher temperatures inside the tank can be set. This easy add-on feature connects the cold inlet and hot outlet, mixing both cold and hot water, resulting in the lower outgoing temperature delivered to all fixtures. This way, water will be delivered at safe temperatures - preventing injuries from scalding. Since hot water can be stored at the higher temperature, there is less Legionella growth inside the tank. Per the manufacturer info, this type of booster can increase usable water up to more than 200%, but it varies.
There are also other available options for getting hot water faster. One of the options is to install a circulation pump, such as this Grundfos and a dedicated line from the water heater to the point-of-service, or installing an instant hot water dispenser such as Insinkerator. It all depends on what you need or want.