Tankless water heaters have pretty much become the standard in new construction homes and as their use has proliferated, a new set of issues are arising. We hope this blog helps increase the lifespan of your Tankless, and gives you peace of mind when it comes to your water heater.
Water Pressure
Tankless water heaters work by pulling water over a hot heat exchanger which quickly heats the water to the desired temperature and then a the unit distributes the water through the home. Many of these systems have pumps which recirculate the water through the home so you have instant hot water everywhere in the home. These recirculating systems will not push/circulate the water until it heats to the temperature set on the unit. The hotter the temperature setting the longer the water must be heated by the exchanger.
Most manufacturers recommend you set your tankless to 120 degrees which is how they are designed to operate as efficiently as possible. Tankless water heaters are designed to perform optimally at this setting. We do see some of our Owners request hotter settings and there are ways to do that up to 140 degrees. However there are some drawbacks to doing this.
The hotter you set your temperature, the longer the water must be heated over the heat exchanger, which will lower the volume and/or pressure you receive for your hot water. The end result is the water will be hotter, but you will get less of it. Another issue to be aware of is the longer and hotter you run your Tankless Water Heater, the shorter lifespan it will have!
A Tankless that runs as designed and is serviced regularly (See our GEMS post) can usually go solid for about 12-16 years. With luck and care maybe longer. A tankless that is run hot and hard will have a dramatically shorter life span. We mention this as some Owners will question while their unit cruded out on them after 8 years. There are typically 2 reasons, failure to properly service or running it longer and hotter than typically recommended.
Placement
Tankless units can be mounted in several different locations. Most often they are installed in the interior of the attic, inside of garages or on exterior walls, If you have an encapsulated attic we would recommend placement of the units in the attic. This will help the unit perform more efficiently as it is located within the conditioned space. This will also help the water entering the unit to get to temperature quicker during cold spells as it will warm up inside the insulation envelope.
Freeze Protection
If you have lived in Texas for awhile you either have stories or know someone who has stories from our big freeze event back in 2021. The large amounts of power outages created an assortment of issues including damage to Tankless water heaters. Most of these units have built in heaters which are designed to prevent freezing during cold events, however if the power is out these heaters are of little use. Our recommendation is if you have concerns about power reliability during serious freeze events you should leave your hot water dribbling (more than a drip) so the water continually moves through the Tankless. If the power goes out you won’t get hot water however if you keep the water moving you stand a good change of saving your units from damage. You should also be dribbling your cold water. We recommend you do this at any plumbing fixture on an exterior wall.
Design
A high capacity Tankless water heater can generate about 10 gallons a minute. A typical hot shower uses about 2 gallons per minute. If you have someone taking a shower, someone else doing laundry and running the dishwasher you can quickly exhaust your hot water supply. Most of our homes are designed with the Tankless units working together. This is where we put two Tankless units together so that if the demand for hot water exceeds its capacity the second until will kick on which in effects doubles your capacity. If you have your home split with one Tankless servicing half the home you can have delivery issues when you have high demand periods.
Recirculation
Most Tankless systems have recirculating pumps either built into them or installed alongside them. These help keep hot water constantly moving throughout the house so the wait for hot water is seconds and not minutes at most fixtures. These systems can be set to run several different ways:
- Predictive Software – Many of the units have algorithm software that will learn your usage habits and turn the unit on to run when it anticipates your usage.
- WiFi / Bluetooth – Many systems have WiFi and/or Bluetooth interfaces which allow you to set schedules for times you want hot water and turn on the system during times you need hot water that is not part of the schedule. Some of these WiFi systems have remote buttons or sensors you can use to turn on the system as well. Just push the button and the system starts delivering hot water.
- Keypads – Some systems have wired keypads which allow an Owner to set schedules, turn on the unit and make other setting adjustments. These keypads can be mounted by the unit or remotely in a location within the home for easy access.
- Always On – Some Owners ask us to have the units run continuously. There is a setting that allows us to have them run basically 24/7. This will keep hot water continuously flowing throughout the home, however the units work harder and this may shorten their life span.
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