Stiebel Eltron DHE vs DEL: Which Instant Hot Water Unit Should You Buy?
Same box, same heat, different brain. This is the question we get most about Stiebel Eltron.
In the Stiebel Eltron DHE vs DEL decision, buy the DEL 27 Plus for a house that only needs hot water in bathrooms, and buy the DHE 27 if you need water above 50°C or your mains pressure jumps around. Both put out exactly the same 28 kW. Both carry a 7 year warranty. The DEL 27 Plus costs $1,399 and the DHE 27 costs $1,545, so the real question is whether the DHE's extra 10 degrees and smarter temperature control are worth $146 to you. For most homes, they are not.
Want your exact size? Our instant hot water sizing calculator works out the kW or litres a minute you need in winter, checks single or 3-phase power, then shows the units that fit.
Our picks at a glance
The Stiebel Eltron DEL 27 Plus is our top pick for most 3 phase homes, with the DHE 27 as the upgrade and the DEL 18 Plus for warm climates.
- Best for most homes: Stiebel Eltron DEL 27 Plus, $1,399. 28 kW, capped at 50°C so no tempering valve on bathroom outlets. One shower anywhere on the mainland. View the DEL 27 Plus →
- Best for kitchens, laundries and patchy pressure: Stiebel Eltron DHE 27, $1,545. 28 kW, adjustable to 60°C, 4i control that holds temperature when someone flushes a toilet. View the DHE 27 →
- Best for Brisbane, Perth and Sydney on a smaller supply: Stiebel Eltron DEL 18 Plus, $1,365. 19.4 kW at 27 amps per phase. View the DEL 18 Plus →
Prices current as of October 2026, AUD including GST, unit only.
Stiebel Eltron DHE vs DEL Plus: the spec sheet side by side
The Stiebel Eltron DHE and DEL Plus share the same case, the same heat output, the same switch on flow and the same warranty; the differences are maximum temperature, control electronics, preheat limit and price.
| Spec | DEL 18 Plus | DEL 27 Plus | DHE 18 | DHE 27 |
|---|---|---|---|---|
| Rated output (415V) | 19.4 kW | 28 kW | 19.4 kW | 28 kW |
| Rated current per phase | 27 A | 38.9 A | 27 A | 40 A |
| Temperature range | 20 to 50°C | 20 to 50°C | 20 to 60°C | 20 to 60°C |
| Control technology | 3i | 3i | 4i | 4i |
| Electronic flow rate control | No | No | Yes | Yes |
| Electronic air detection | No | No | Yes | Yes |
| Max preheated inlet water | 50°C | 50°C | 55°C | 55°C |
| Switch on flow | 2.5 L/min | 2.5 L/min | 2.5 L/min | 2.5 L/min |
| Max pressure | 1 MPa | 1 MPa | 1 MPa | 1 MPa |
| Size (H x W x D) | 466 x 225 x 116 mm | 466 x 225 x 116 mm | 466 x 225 x 116 mm | 466 x 225 x 116 mm |
| Sydney winter flow at 40°C | About 10.3 L/min | About 14.8 L/min | About 10.3 L/min | About 14.8 L/min |
| Warranty (domestic) | 7 years | 7 years | 7 years | 7 years |
| Price | $1,365 | $1,399 | $1,415 | $1,545 |
Specs from the Stiebel Eltron technical data on each product page. Flow figures are our worked estimates for a typical Sydney winter mains temperature. Prices current as of October 2026, AUD including GST.
Read that table twice and you notice something. Heat output is identical. A DHE 27 does not make hotter showers than a DEL 27 Plus. It makes steadier ones, and it can go hotter for jobs that are not showers.
Where the DEL Plus wins
The Stiebel Eltron DEL Plus wins on bathroom only installs, because its 50°C cap means no tempering valve and its price undercuts the DHE at both sizes.
Australian rules want bathroom hot water delivered at no more than 50°C in most new and replacement installs. Our explainer on the 50 degree hot water rule covers the detail. A heater that physically cannot exceed 50°C keeps that part of the job simple. Your plumber confirms what your local rules need, but on a bathroom only unit the DEL is the clean answer.
You still get the good bits. Half degree adjustment for showers. A backlit display showing set temperature and power draw. ECO mode. Two memory buttons, so the person who showers at 38 and the one who showers at 43 can stop fighting about the dial.
And the price gap at 28 kW is $146. That buys a fair chunk of the electrician's afternoon.
Where the DHE earns its extra money
The Stiebel Eltron DHE earns its higher price in three situations: the unit feeds a kitchen or laundry that wants water above 50°C, the house has unsteady mains pressure, or the unit boosts a solar or heat pump preheat tank running between 50 and 55°C.
Hotter water. The DHE goes to 60°C. That matters for greasy dishes and a laundry tub. If one unit has to run the whole house, kitchen included, the DHE does the lot. Bathroom outlets then usually need a tempering valve, which the plumber fits.
Pressure swings. 4i technology compensates for changes in water pressure and incoming temperature, and the DHE adds electronic flow rate control on top. In plain terms: someone flushes the toilet, the pressure dips, and a DHE holds your shower within a degree where a DEL may wobble for a second or two. On a house with steady town water pressure you will rarely notice. On an older house with tired pipes, or a property on a pressure pump, you will.
Preheat. The DHE accepts preheated water up to 55°C against 50°C for the DEL Plus. If it sits after a solar tank that runs hot in summer, the DHE gives you more headroom.
The DHE also has electronic air detection, which protects the bare wire element if air gets into the line after the water is shut off for maintenance. Nice to have. Not a reason to buy on its own.
18 or 27: picking the size
Pick the 27 size (28 kW) for one shower in Melbourne, Adelaide, Canberra or Hobart, and the 18 size (19.4 kW) is enough for one shower in Brisbane, Perth or Sydney.
Cold mains water is the whole story. A Canberra winter feeds the heater water close to single digits, and lifting that to 40°C at shower flow takes about 21 kW. Brisbane needs closer to 15 kW. Sydney sits around 17 kW and Melbourne around 19 kW, which is right on the edge of what a 19.4 kW unit can do.
Our honest advice: if your switchboard and supply can carry the 27, buy the 27. On the DEL range the step up from 18 to 27 is only $34. On the DHE range it is $130. Either way it is the cheapest insurance against a lukewarm July.
The catch is current. The DEL 27 Plus draws 38.9 amps per phase and the DHE 27 draws 40 amps, against 27 amps for either 18. Your electrician checks the supply and switchboard can take it before you order. If you are not sure you have 3 phase at all, read single phase vs 3 phase instant hot water first. These are 3 phase units only. There is no single phase version.
The cheaper option nobody asks about
The Stiebel Eltron DHB-E 18 LCD at $1,139 is the cheapest 19.4 kW unit in the range, and it suits a one shower home in a warm city on a budget.
It adjusts from 20 to 60°C, carries the same 7 year domestic warranty, and accepts preheated water up to 55°C. It drops the memory buttons and ECO mode. For a rental or an investment property in Brisbane, it is often the smarter buy than either the DEL or the DHE.
What none of these units will do
No single Stiebel Eltron DEL or DHE will run two showers at the same time in winter, at any size.
28 kW gives roughly 13 to 17 litres a minute at 40°C depending on your city. A standard shower uses about 9. Two showers want 18. The maths does not work. If two people shower at once every morning, you want gas continuous flow, like the Midea M20 in warm cities or the Midea M26 in Melbourne, Adelaide and colder. For the whole Stiebel lineup, including the single phase basin units, see our Stiebel Eltron models compared guide.
Our verdict on the Stiebel Eltron DHE vs DEL
The Stiebel Eltron DEL 27 Plus is the better buy for about eight in ten 3 phase homes we talk to.
It is $146 cheaper than the DHE 27, puts out the same heat, and the 50°C cap keeps bathroom installs simple. Buy the DHE when the unit feeds a kitchen or laundry, when your water pressure is unreliable, or when you just want the best Stiebel makes and do not mind paying for it. Nobody regrets a DHE. Plenty of people did not need one.
Frequently asked questions
What is the difference between the Stiebel Eltron DHE and DEL Plus?
The Stiebel Eltron DEL Plus is capped at 50°C and uses 3i control, while the DHE adjusts up to 60°C and uses 4i control with electronic flow rate control that holds temperature more precisely when water pressure changes. Both come in 19.4 kW and 28 kW sizes with identical heat output, the same dimensions and a 7 year domestic warranty.
Is the Stiebel Eltron DHE worth the extra money in Australia?
The Stiebel Eltron DHE is worth the extra money in Australia only if the unit must supply water above 50°C, the home has unsteady mains pressure, or it boosts preheated water between 50 and 55°C. For a bathroom only install, the DEL Plus delivers the same heat for $50 less at 19.4 kW and $146 less at 28 kW (prices as of October 2026).
Does the Stiebel Eltron DEL Plus need a tempering valve?
The Stiebel Eltron DEL Plus is capped at a maximum output of 50°C, so Stiebel Eltron states no tempering valve is needed for bathroom outlets. Your licensed plumber confirms the final requirement under your local installation rules.
Which Stiebel Eltron unit do I need for Melbourne or Canberra?
A home in Melbourne or Canberra needs a 28 kW Stiebel Eltron unit, either the DEL 27 Plus or the DHE 27, for one comfortable winter shower. A 19.4 kW unit only just covers the roughly 19 kW a Melbourne winter shower needs and falls short of the roughly 21 kW Canberra needs.
Can a Stiebel Eltron DHE 27 or DEL 27 Plus run two showers at once?
A Stiebel Eltron DHE 27 or DEL 27 Plus cannot run two standard showers at once in winter, because 28 kW delivers roughly 13 to 17 litres a minute at 40°C and two showers need about 18. Homes with two simultaneous showers are better served by gas continuous flow at 20 or 26 litres a minute.
How many amps does a Stiebel Eltron DEL 27 Plus or DHE 27 draw?
The Stiebel Eltron DEL 27 Plus draws 38.9 amps per phase and the DHE 27 draws 40 amps per phase on a 415V 3 phase supply. The 19.4 kW DEL 18 Plus and DHE 18 each draw 27 amps per phase.
Still not sure which one fits?
Send us your suburb, what the unit has to supply and a photo of your switchboard, and we will tell you straight whether it is the DEL, the DHE, or gas. Usually takes one email.
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This guide is general information for Australian households and is not a substitute for advice on your specific home and site. Flow figures are worked estimates based on typical winter mains temperatures. Electric instantaneous water heaters must be installed by a licensed electrician and plumber, on a dedicated circuit sized to the unit. 3-phase units need a 3-phase power supply, and any supply upgrade must be arranged through a licensed electrician and your network provider. Gas continuous flow units must be installed by a licensed gas fitter. Confirm final sizing with us or your installer before you buy.