Outdoor tankless electric water heaters are the go-to solution for homeowners and businesses who want instant hot water without sacrificing indoor space. Whether you’re setting up an outdoor kitchen, a poolside shower, a remote guest cabin, or simply prefer installing your unit outside to free up indoor room, an outdoor electric tankless water heater delivers hot water on demand while keeping things compact, clean, and efficient.
In this guide, we’ll explore the best outdoor tankless electric water heaters for 2025, how they’re different from standard indoor units, and what features to look for. We’ll also cover installation tips, maintenance advice, and one often-overlooked plumbing factor that could save you from costly repairs.
Why Choose an Outdoor Electric Tankless Water Heater?
Here’s why many homeowners and commercial property owners prefer outdoor installation:
- Space savings: Keep your utility areas uncluttered by installing the unit outside.
- No venting required: Outdoor electric units naturally vent heat without needing special exhaust systems.
- Energy efficiency: Heats water only when needed—no standby energy losses.
- Easy service access: Technicians can perform maintenance without entering your home or business.
- Weather-resistant design: Outdoor-rated units are built to withstand rain, sun, and temperature changes.
Best Overall: Stiebel Eltron DHC-E Outdoor Series
The Stiebel Eltron DHC-E Outdoor is a purpose-built electric tankless water heater designed for permanent outdoor installation. Known for German engineering and reliability, it’s ideal for residential or light commercial outdoor setups.
- Power: Available in multiple kW sizes to match demand.
- Rugged, weatherproof casing for year-round outdoor use.
- Precise electronic temperature control.
- Quiet operation, making it perfect for poolside or garden areas.
Other Top Outdoor Tankless Electric Water Heaters
Rheem Outdoor Electric Series
Designed for the Australian and US markets, Rheem’s outdoor electric units offer strong performance, easy installation, and robust weather resistance.
Bosch Tronic Outdoor Adapted Units
Bosch’s Tronic range includes models that can be adapted for outdoor use with protective housings, perfect for climates that don’t experience freezing temperatures.
EcoSmart Outdoor Conversion Setup
EcoSmart’s electric models can be mounted outdoors with appropriate weatherproof enclosures, making them a flexible choice for both indoor and outdoor needs.
Eemax Outdoor Commercial Units
For high-demand situations like beachside facilities or outdoor sports clubs, Eemax offers commercial-grade electric models rated for exterior installation.
How to Choose the Right Outdoor Tankless Electric Water Heater
Before buying, consider these important factors:
- Climate: In freezing regions, ensure the unit has built-in freeze protection or install it in a sheltered location.
- Power supply: Outdoor electric units may require dedicated high-amperage circuits—check your electrical panel’s capacity.
- Hot water demand: Calculate peak flow rate needs for your outdoor setup (e.g., shower + kitchen sink).
- Durability: Look for corrosion-resistant materials to handle coastal or humid conditions.
- Maintenance access: Even outdoors, the unit should be installed where it can be serviced easily.
Pro Tip: If you live in a coastal area, choose a marine-grade stainless steel unit to prevent salt corrosion.
Installation Tips for Outdoor Units
Outdoor tankless electric water heaters are generally easier to install than gas units, but you should still follow best practices:
- Use a weatherproof electrical connection and conduit rated for outdoor exposure.
- Mount the unit on a secure, level surface away from direct sprinkler spray.
- Ensure proper drainage below the unit in case of leaks or overflow.
- For colder climates, insulate exposed pipes and consider a freeze-protected model.
Maintenance for Long-Lasting Performance
With proper care, an outdoor tankless electric water heater can last 15–20 years. Key maintenance tasks include:
- Annual descaling in hard water areas to prevent mineral buildup.
- Cleaning inlet filters to maintain water flow.
- Checking for signs of corrosion or weather damage on the casing.
- Inspecting electrical connections annually for safety.
The Overlooked Side of Your Plumbing System
Outdoor hot water setups are great, but what happens after the water goes down the drain? If your property uses a septic system, increased hot water use can stress a poorly maintained tank, leading to odours, clogs, and expensive repairs.
Homeowners often forget that septic health is part of the whole water system. Preventative care is much cheaper than emergency fixes—and it ensures everything works smoothly year-round.
SEPTIFIX – Keep Your Septic System Healthy
SEPTIFIX is the #1 septic tank treatment in the US, Canada, and Australia, trusted by thousands of property owners. These flushable tablets release oxygen and beneficial bacteria to break down waste, sludge, and grease while neutralising unpleasant smells.
Benefits include:
- Eliminates odours within days.
- Prevents backups and costly pump-outs.
- Safe for all septic and plumbing systems.
- Easy to use—flush one tablet monthly.
Pairing your outdoor tankless electric water heater with regular SEPTIFIX treatment ensures your property’s water systems—from heating to drainage—stay in perfect condition.
Final Thoughts
For 2025, the Stiebel Eltron DHC-E Outdoor Series leads the pack for outdoor tankless electric water heaters, offering durability, precision, and reliable performance in various climates. The Rheem Outdoor Electric Series, Bosch Tronic adaptations, EcoSmart outdoor conversions, and Eemax outdoor units also provide excellent choices for different budgets and needs.
And remember—hot water is only one part of the equation. Keeping your septic system healthy with SEPTIFIX ensures your plumbing runs smoothly, indoors and out.
Order SEPTIFIX Today – Protect Your Septic Tank and Keep Your Water Systems Running Smoothly
Reliable outdoor hot water and a trouble-free septic system—that’s smart, sustainable living.