Answering the common search: tankless water heaters that offer recirculation to minimize wait time for hot water. This guide compares five top options, highlighting who each model is best for and where one might outperform another. Ideal buyers include busy households needing instant hot water, homes with long pipe runs, and those upgrading from traditional tanks.
| Product | Best For | |
|---|---|---|
| Rheem RTGH-RH11DVLN | Families wanting fast hot water | Built-in recirculation, high efficiency, space-saving |
| Rinnai RXP160iN | Compact, flexible installs | Versa Vent, indoor/outdoor install options, Smart Sense controls |
| Rinnai RU199iN | Whole-home capacity with recirculation | Circ-Logic external pump readiness, strong flow |
| MIZUDO 199k BTU | Large homes with multiple simultaneous demands | High input, precise temp control |
| Watts H2O 0955805 | Easy retrofit for existing systems | Programmed recirculation, DIY-friendly |
Rheem Prestige Condensing Tankless with Built-in Recirculation
This unit combines a compact indoor design with a built-in recirculation feature and high efficiency. It is best for homes replacing a traditional tank where space is limited and hot water waits must be minimized. The model emphasizes savings on hot water while keeping operating costs manageable for a mid-sized household. A potential limitation is the need for precise venting and space considerations in retrofit projects.
Rinnai RXP160iN Condensing Smart Sense
Best for flexible installation, the RXP160iN offers indoor/outdoor versatility via Versa Vent and supports natural gas or propane with Smart Sense control. Its compact profile makes it suitable for spaces where layout flexibility matters. The unit is ideal for small to medium homes that want rapid hot water delivery with efficient operation. Limitations include the need for proper venting considerations and the external control module for full remote features.
Rinnai RU199iN Condensing Tankless 11 GPM
Best for whole-home performance with recirculation features, the RU199iN delivers up to 11 GPM and supports Circ-Logic for pairing with an external pump to optimize hot water timing. It’s well-suited for larger households with multiple simultaneous uses. A clear caveat is that advanced features may require additional components (e.g., an external pump) to achieve optimal recirculation results.
MIZUDO Natural Gas Tankless, 199,000 BTU
Best for large households with heavy simultaneous hot-water demands, this model offers high input and precise temperature control. It supports up to 10.3 GPM and can maintain comfort across multiple fixtures. A notable limitation is the higher BTU requirement, which may demand a compatible gas supply and proper venting in retrofit scenarios.
Watts Heat H2O 0955805 Recirculation System
Best for homeowners looking to retrofit for instant hot water, this programmable timer system uses thermal bypass technology to deliver hot water quickly at faucets and showers. It is not designed to work with every tankless model, so ensure compatibility prior to purchase. The system is easy to install for DIY enthusiasts and supports significant water conservation benefits.
Buying Guide: Key Purchase Considerations
- Flow rate needs: Determine peak simultaneous hot water usage (fixtures, showers, and appliances) to pick a model with adequate GPM.
- Recirculation approach: Decide between built-in recirculation (simpler install) and external pump systems that pair with Circ-Logic or equivalent controls.
- Vent and fuel compatibility: Gas models require proper venting and gas supply capacity; propane vs natural gas may influence model choice.
- Space and installation: Consider indoor vs outdoor installation, venting requirements, and whether the unit fits your living space.
- Energy efficiency: Look for high UEF or equivalent efficiency metrics, especially when replacing an old tank.
- Upgrade compatibility: If retrofitting, ensure compatibility with existing piping, return lines, or external pumps.
Frequently Asked Questions
- What is a tankless water heater with recirculation?
It is a point-of-use or whole-home heater designed to deliver hot water with a built-in or connected recirculation path, reducing wait time at taps.
- Do all recirculation systems require a return line?
No. Some systems use a thermal bypass and do not require an additional dedicated return line, simplifying installation.
- Which is better for a small home: built-in recirculation or external pump recirculation?
Built-in recirculation is typically easier to install, while external pumps can offer more customizable recirculation timing for larger homes.
- Can these systems be installed indoors in tight spaces?
Yes, many models are designed for indoor installation, but check venting, clearance, and service access requirements for your space.
- Do tankless recirculation systems save water?
Yes, by reducing wait time for hot water, they minimize water waste at the taps, especially in longer pipe runs.
- Is professional installation recommended?
For gas models and complex recirculation setups, professional installation is advised to ensure safe venting and proper operation.