Yes, a tankless water heater can be installed outside, but it must be properly insulated and rated for cold climates to withstand snow and freezing temperatures.
Many homeowners consider outdoor installation for tankless water heaters to save space. But cold weather poses unique challenges. Proper winterization is critical to prevent freeze damage.
Outdoor Tankless Water Heater Installation Considerations
Most manufacturers approve outdoor installation, but with important caveats for cold climates:
- Northern exposure units face higher freeze risk
- Western exposures get afternoon sun but face evening temperature drops
- Units must have built-in freeze protection or supplemental heating
Freeze Protection Requirements
Modern units include basic freeze protection that activates at about 37°F. This feature:
- Circulates warm water when temperatures drop
- Uses small amounts of electricity to prevent freezing
- Works only when power is available
Winterizing Your Outdoor Tankless Water Heater
Follow these steps to protect your investment:
Insulation Strategies
| Component | Insulation Method |
|---|---|
| Water pipes | Foam pipe insulation sleeves |
| Unit body | Insulated blanket or cover |
| Exposed valves | Heat tape with thermostat |
Emergency Preparedness
During extreme cold snaps:
- Keep a slow drip (5 drops per minute) at faucets
- Open cabinet doors to allow warm air circulation
- Know your water heater’s minimum safe temperature
Manufacturer-Specific Recommendations
Different brands have varying cold weather requirements:
Rinnai
Their outdoor models feature:
- Self-draining design when not in use
- Heated freeze protection board
- Minimum operating temperature of -22°F
Navien
This brand recommends:
- Recirculation mode for constant flow
- External insulation jacket below 20°F
- Battery backup for power outages
Alternative Solutions for Extreme Climates
For areas with prolonged sub-freezing temperatures:
Indoor Installation
Consider moving the unit to a garage or basement. This provides natural protection and easier access for home temperature regulation.
Hybrid Systems
Some homeowners install:
- Small tank water heater as backup
- Secondary heat exchanger
- Dual-fuel systems
According to Frisco’s Public Works Department, outdoor units on north or west exposures need special attention during extended freezes.
The Rooter Man guide emphasizes checking outdoor vents regularly for snow and ice buildup.
