6 Stiebel Eltron Water Heater Questions Installers Actually Ask: What I Learned Ordering for 400+ People

What I’ve Learned Ordering Stiebel Eltron Water Heaters for 3 Locations

I’m an office administrator for a mid-sized company—about 400 employees across three buildings. I manage all service and equipment purchasing, roughly $150,000 annually across a dozen vendors. That includes water heaters, among other things.

When I took over purchasing in 2020, I inherited a mix of brands. Stiebel Eltron was one of them. I’m not a plumber or an HVAC engineer, so I can’t speak to technical specs in detail. But from a procurement and coordination standpoint? I’ve seen which products hold up, which ones cause headaches, and which questions keep coming up from our maintenance team.

Here are the six most common things people ask me about Stiebel Eltron—answered the way I wish someone had explained them to me.

1. What makes Stiebel Eltron different from brands like Rheem or Bosch?

From my perspective, the biggest difference isn’t the price tag—it’s the staying power. We installed a Stiebel Eltron Tempra Plus in 2021 for one of our satellite offices. It’s been running consistently with zero service calls. I can’t say that for every brand we’ve used.

The German engineering isn’t just marketing—it shows in the build quality. The units feel solid, the connections are clean, and our maintenance guys actually comment on how easy they are to work on. That matters when you’re coordinating service across multiple locations.

To be fair, Rheem has better availability at some distributors, and Bosch has a wider network. But for longevity? Stiebel Eltron has been the less headache-prone option in my experience.

2. Why is my Stiebel Eltron water heater not heating?

This is probably the most common call I get from our facility team. Nine times out of ten, it’s not the unit itself—it’s something on the input side.

I’m not an electrician, so I can’t diagnose wiring. But what I’ve seen repeatedly:

• Tripped breaker – The unit pulls a lot of current. If other equipment is on the same circuit, it’ll trip. That happened to us twice before we realized the breaker was undersized.
• Inlet water too cold – In winter, incoming ground water can drop into the 40s (F). The heater can only raise the temperature so much. If you’re expecting 110°F output and the water comes in at 45°F, you might get lukewarm water instead of hot.
• Flow rate too high – The heater only activates when there’s enough flow. If a faucet is barely open, the unit may not turn on at all.

One time, our maintenance lead called me panicked because a Tempra wasn’t heating. Turned out someone had partially closed the shutoff valve during cleaning. Check the simple stuff first.

3. Is the Tempra Plus worth the extra cost compared to the standard Tempra?

Let’s do a quick math exercise. I get why people look at the price difference and consider the standard model. It’s cheaper upfront. But here’s where my “value over price” stance kicks in.

My experience is based on maybe 12–15 installations across three buildings. In 2023, we replaced a standard Tempra that had been installed in 2018. Not a failure, but the flow rate wasn’t sufficient after we added a second bathroom to that office. With the Tempra Plus, we got the higher flow capacity and didn’t need to upgrade the electrical.

The Tempra Plus also includes a digital display and more precise temperature control. That’s not just a gimmick—our facilities guys set it once and haven’t touched it since. Less fiddling means fewer complaints from staff about inconsistent water temperature.

So is it worth it? If you’re installing for a single-sink application, maybe not. If it’s for an office with multiple points of use? Absolutely. The $150–$300 premium pays for itself in avoided headaches.

4. How does Stiebel Eltron compare to a tankless gas water heater?

This is a fair question, and honestly, I don’t have direct experience with gas tankless units in our buildings. What I can tell you is why we stuck with electric.

Gas requires venting. That means either a chimney or a side-wall vent. In one of our older buildings, installing a gas line would have meant cutting through two floors of finished space. The electric Stiebel Eltron units just needed a breaker and a water line. Installation took one guy half a day.

Maintenance is also simpler. No combustion chamber to clean, no burners to foul. The electric elements are straightforward.

From a cost perspective, gas can be cheaper per BTU in some regions. But when you factor in installation complexity and ongoing maintenance, the electric option often comes out ahead—especially in retrofit situations.

5. What maintenance does a Stiebel Eltron tankless water heater need?

I’m going to be honest: we neglected this at first. The “maintenance-free” marketing language made us think we could just install and forget. That worked for about two years. Then we started noticing slightly lower flow in one unit.

The real maintenance is simple: descaling. If you have hard water, mineral buildup will eventually restrict the heat exchanger. Our water is moderately hard (around 7–8 grains). We now flush the unit with a vinegar solution every 12 months.

Our maintenance lead built a simple setup: bucket, submersible pump, hose to the unit’s inlet, and a hose from the outlet back to the bucket. Run the vinegar solution through for 45 minutes, then rinse with clean water. We schedule this for all three buildings on the same day. Takes about 2 hours total.

We also check the inlet filter annually. That’s just a screen that catches debris from the water line. Clean it if it’s clogged.

Skipping this step? I wouldn’t recommend it. The third time we had to swap out a flow sensor, I finally created a checklist. Should have done it earlier.

6. What’s the one thing most installers don’t know about Stiebel Eltron?

Here’s the one I always mention: the flow rate variance depending on electrical supply. The Tempra Plus 24 kW model, for example, requires two 40-amp breakers. But if your electrical service can’t deliver that consistently—especially in an older building with other loads—you’ll get reduced performance.

Getting into electrical territory, which is a bit beyond my expertise. But what I can tell you from my procurement perspective: make sure your electrician actually verifies the wire gauge and breaker capacity before you order the unit. We learned this the hard way when a 24 kW unit was installed in a building that had only 100-amp service. The heater worked, but everything else on that panel dimmed when it kicked on.

Also worth mentioning: Stiebel Eltron makes a whole range beyond just tankless. Their heat pump water heaters are pretty amazing for energy efficiency—roughly 3.5 COP, which is industry competitive. But those also need proper space for air intake and exhaust.

One last thing… I understand why people lean toward the cheapest buddy heater or oxyshred fat burner for personal use. But for commercial applications where reliability affects 400 people? Don’t skimp. The upfront savings aren’t worth the downtime.