STIEBEL ELTRON · TANKLESS WATER HEATERSThe Stiebel Eltron space at AirGreenThe Tempra Trend and Plus we sell, sized with Stiebel’s own figures, for Montreal, Laval, Longueuil, the South Shore and the North Shore.

Mon–Thu 8 a.m.–6 p.m. · Fri 8 a.m.–4 p.m.

Stiebel Eltron · Tempra Trend and Plus · Updated October 20, 2026

Stiebel Eltron tankless water heaters: size it by the showers you run at once

A Tempra heats water as it flows, with no tank. Its size depends on three things: power (14.4 to 36 kW), the temperature of the water coming in during winter, and how many taps run at the same time. The technical figures come from Stiebel Eltron’s own documents, and every calculation is shown.

Count my showers See the models

Stiebel’s table, in showers

How many showers at once?

Maximum flow at 105 °F (40.6 °C), 240 V, from the Stiebel Eltron sizing guide. One drop = one 1.5 gpm (5.7 L/min) shower, Stiebel’s assumption. Pick the temperature of the water coming in.

Tempra15

Tempra20

Tempra24

Tempra29

Tempra36

3.0 gpm

4.0 gpm

5.0 gpm

6.0 gpm

7.5 gpm

2.3 gpm

3.1 gpm

3.8 gpm

4.6 gpm

5.7 gpm

1.9 gpm

2.5 gpm

3.1 gpm

3.7 gpm

4.6 gpm

1.6 gpm

2.1 gpm

2.6 gpm

3.1 gpm

3.9 gpm

With water coming in at 42 °F (5.6 °C), a Tempra 29 or 36 runs 2 showers at once; a Tempra 15, 20 or 24 runs one.

14.4 to 36 kWat 240 V (10.8 to 27 kW at 208 V)

2 or 3dedicated circuits, by model

7 yrs / 3 yrsStiebel warranty: leaks / defects

100–300 Amain service Stiebel recommends

AirGreen × STIEBEL ELTRONTempra Trend and Plus14.4 to 36 kW at 240 VStiebel Eltron, since 1924Stiebel warranty: 7 yrs leaks, 3 yrs defectsElectrical: RBQ 16Montreal · Laval · Longueuil · South Shore · North Shore

01 · The Tempra range

Five power sizes, two versions, one cabinet

All ten models share the same cabinet (16 5/8 × 14 1/2 × 4 5/8 in) and 3/4 in NPT water connections. What changes from one to the next: power, number of circuits and what your electrical service must be able to supply.

Tempra 15

14.4 kW at 240 V

2 circuits · 2 × 30 A
4 heating elements
Recommended service: 100 A

Trend Plus

Tempra 20

19.2 kW at 240 V

2 circuits · 2 × 40 A
4 heating elements
Recommended service: 125 A

Trend Plus

Tempra 24

24 kW at 240 V

2 circuits · 2 × 50 A
6 heating elements
Recommended service: 150 A

Trend Plus

Tempra 29

28.8 kW at 240 V

3 circuits · 3 × 40 A
6 heating elements
Recommended service: 200 A

Trend Plus

Tempra 36

36 kW at 240 V

3 circuits · 3 × 50 A
9 heating elements
Recommended service: 300 A

Trend Plus

Stiebel Eltron’s data, model by model

Stiebel Eltron technical data for the Tempra
Model	Part no. Trend / Plus	Power	Double-pole breakers	Copper wire	Elements	Flow to start	Weight	Recommended service
Tempra 15	239214 / 239220	14.4 kW	2 × 30 A	2 × 10/2 AWG	4	0.50 gpm	16.1 lb (7.3 kg)	100 A
Tempra 20	239215 / 239221	19.2 kW	2 × 40 A	2 × 8/2 AWG	4	0.50 gpm	16.1 lb (7.3 kg)	125 A
Tempra 24	239216 / 239222	24 kW	2 × 50 A	2 × 8/2 AWG	6	0.50 gpm	16.1 lb (7.3 kg)	150 A
Tempra 29	239217 / 239223	28.8 kW	3 × 40 A	3 × 8/2 AWG	6	0.77 gpm	19 lb (8.6 kg)	200 A
Tempra 36	239218 / 239225	36 kW	3 × 50 A	3 × 8/2 AWG	9	0.77 gpm	19 lb (8.6 kg)	300 A

The number in the name is a model designation, not the exact power. A Tempra 15 gives 14.4 kW at 240 V, a Tempra 20 gives 19.2 kW and a Tempra 29 gives 28.8 kW (Stiebel spec sheet, rev. 6.2025). At 208 V, power drops by about a quarter, so Stiebel advises going one model up.

02 · How many showers at once

How many showers at the same time? Run Stiebel’s math

Enter the temperature of the water coming in and what runs at the same time. The tool applies the formula Stiebel Eltron publishes: gpm = kW × 6.83 ÷ temperature rise in °F, with the flow rates from Stiebel’s sizing guide.

Water coming into the house

42 °F · 5.6 °C

Available voltage

What runs at the same time

Showers1.5 gpm at 105 °F

Kitchen sink1.0 gpm at 105 °F

Bathroom sinks0.5 gpm at 90 °F

Your result

Power needed

27.7 kW

2 showers × 1.5 gpm × (105 − 42) °F ÷ 6.83 = 27.7 kW at 240 V

Tempra 15

14.4 kW · too small

Tempra 20

19.2 kW · too small

Tempra 24

24 kW · too small

Tempra 29

28.8 kW · enough

Tempra 36

36 kW · enough

Smallest model that is enough: Tempra 29 (Trend or Plus).

Stiebel’s table: maximum flow at 105 °F (40.6 °C), in gpm, at 240 V

Incoming water	Tempra 15	Tempra 20	Tempra 24	Tempra 29	Tempra 36
72 °F (22.2 °C)	3.0	4.0	5.0	6.0	7.5
62 °F (16.7 °C)	2.3	3.1	3.8	4.6	5.7
52 °F (11.1 °C)	1.9	2.5	3.1	3.7	4.6
42 °F (5.6 °C)	1.6	2.1	2.6	3.1	3.9

Read this before you choose. Incoming water temperature changes with the season and the location; Stiebel publishes no value for Québec, hence the slider. In winter, use the coldest row. At 208 V, the tool uses the 208 V power from Stiebel’s spec sheet (Stiebel also advises going one model up). A shower head that flows more than 1.5 gpm needs more power.

AirGreen × STIEBEL ELTRON

Stiebel’s water heater, AirGreen’s math.

Stiebel Eltron designs the Tempra and publishes its power, flow rates and electrical requirements. AirGreen starts from those numbers to propose the size that is enough, no more, no less.

What Stiebel Eltron brings

Five sizes, two versionsFrom 14.4 to 36 kW at 240 V, in Trend or Plus.
Published figuresFlow rates, temperature rise, breakers and recommended main service, model by model.
Advanced Flow ControlOn the Plus: flow drops to hold the temperature, per Stiebel.
7-year / 3-year warrantyLeaks / defects in materials or workmanship, as Stiebel writes it.

What AirGreen brings

The math, done with youYour showers, your incoming water and your panel, with Stiebel’s figures.
Price on quotationFree quotation for the unit and the work.
RBQ 5645-9605-01Subclasses 15.8, 15.10 and 16. Plumbing falls under subclass 15.5, which AirGreen does not hold.
Showroom in Boucherville1370 Joliot-Curie St., unit 712.

The result: the Tempra that is enough for your showers and your panel, not a bigger one.

Count my showers Request a quote

03 · Your electrical service

Before you pick a model, look at your panel

For each Tempra, Stiebel Eltron recommends a minimum main service, “depending on total electric load at the installation site”. Enter yours: the page compares it with Stiebel’s recommendation.

Your main service (main breaker)

With 200 A, the Tempra 15, 20, 24 and 29 are within Stiebel’s recommendation. Your result from section 02: Tempra 29 (outlined).

Tempra 152 dedicated circuits · 2 × 30 A · 2 × 10/2 AWG · Stiebel recommends 100 AWithin the recommendation

Tempra 202 dedicated circuits · 2 × 40 A · 2 × 8/2 AWG · Stiebel recommends 125 AWithin the recommendation

Tempra 242 dedicated circuits · 2 × 50 A · 2 × 8/2 AWG · Stiebel recommends 150 AWithin the recommendation

Tempra 293 dedicated circuits · 3 × 40 A · 3 × 8/2 AWG · Stiebel recommends 200 AWithin the recommendation

Tempra 363 dedicated circuits · 3 × 50 A · 3 × 8/2 AWG · Stiebel recommends 300 ALoad calculation needed

This is not a load calculation. Stiebel’s recommendation is a minimum: a master electrician checks the whole house load (baseboards, range, EV charger…) under the Québec Construction Code, Chapter V – Electricity (2021 Canadian Electrical Code, in force in Québec since March 26, 2026, with a transition period until October 2027). Stiebel sizes breakers at 100% of the load; the electrician confirms this under the Code. AirGreen holds RBQ subclass 16 (electricity).

04 · Trend or Plus

Trend or Plus: it all comes down to asking for too much

Both versions self-modulate. The Plus adds Stiebel’s Advanced Flow Control: when you ask for more hot water than the unit can heat, it “will automatically reduce the flow rate to ensure that the hot water delivered stays at the desired temperature”. Try a demanding situation.

Model

Incoming water

Requested flow (setpoint 105 °F / 40.6 °C)

Tempra Trend

79 °F (26.1 °C) · 4.5 gpm

Flow stays at 4.5 gpm, but the unit can only raise the water by 37 °F (Stiebel table): it comes out lukewarm.

Tempra Plus

105 °F (40.6 °C) · 2.6 gpm

Advanced Flow Control cuts flow to 2.6 gpm (24 kW × 6.83 ÷ 63 °F) to keep the water at 105 °F.

Maximum temperature rise from Stiebel’s 240 V table (spec sheet rev. 6.2025); Plus flow = kW × 6.83 ÷ rise in °F.

What Stiebel publishes	Trend	Plus
Advanced Flow Control (German patent DE 3805441)	No	Yes
Self-modulation: draws only the power it needs	Yes	Yes
Digital temperature display	Yes	Yes
Optional hot water limit at 109 °F (42.8 °C)	Yes	Yes
Adjustable setpoint	68 to 140 °F (20 to 60 °C)	68 to 140 °F (20 to 60 °C)

05 · Installation in Québec

A tankless water heater takes two trades and two licence subclasses

Stiebel Eltron says so in its manual: the unit “must be installed by a licensed electrician and plumber”. In Québec, each part falls under its own RBQ licence subclass.

Electrical · RBQ 16

The electrical hookup

One dedicated circuit per element group, each with its own double-pole breaker: 2 circuits (Tempra 15, 20, 24) or 3 (Tempra 29, 36).
Copper conductors rated 75 °C or higher and voltage drop under 3%, per Stiebel.
Work reserved for an electrical contractor (subclass 16, CMEQ). AirGreen holds this subclass.

Plumbing · RBQ 15.5

The water hookup

3/4 in NPT connections; 30 to 150 psi, pressure-reducing valve required above 150 psi.
Stiebel does not require a temperature and pressure relief valve; if the inspector asks for one, it goes on the hot water outlet.
Work reserved for a plumbing contractor (subclass 15.5, CMMTQ). This part must be done by a 15.5 holder: AirGreen does not hold this subclass.

Stiebel Eltron Tempra tankless water heater mounted on a laundry room wall

Safety and care

What to know

In Québec, shower and bathtub water is limited to 49 °C at the outlet (Construction Code, Chapter III, art. 2.2.10.7). The Tempra can cap hot water at 109 °F (42.8 °C), per Stiebel.
Depending on water hardness, the unit may need descaling every 6 to 12 months, per Stiebel; scale damage is not covered.
No vent or flue: the unit is electric. Incoming water 131 °F (55 °C) maximum.

Furnace or baseboards? A Tempra only heats domestic water. For home heating, see our heat pumps.

06 · The Stiebel Eltron warranty

7 years against leaks, 3 years against defects: read the conditions

Stiebel’s warranty for tankless electric water heaters covers the Tempra models. Here is what it says, and nothing more.

The conditions

Runs from the purchase date (dated proof of purchase; otherwise, the manufacturing date stamped on the unit).
Labour, removal and shipping are at the owner’s expense. Stiebel repairs, supplies the part or replaces the unit, at its option.
Manufacturer liability limited to the price paid for the unit.
Restricted to the owner and cannot be assigned; valid in the U.S.A. and Canada.
Exclusions: hard or corrosive water, freezing, fluctuating pressure, installation not as directed, unit moved.
The installation manual asks you to register the unit online within 90 days of purchase “in order to activate the standard warranty” (the warranty document itself does not mention it).

Purchase date

January 18, 2027online registration (90 days)

October 20, 2029end of defect coverage

October 20, 2033end of leak coverage

Dates computed from the purchase date entered. Québec’s legal warranty is not covered here.

07 · Rebates and standards 2026

No program we checked pays for an electric tankless water heater in 2026

We checked each program below on its own website on October 20, 2026: none pays for a Tempra. If someone promises otherwise, ask for the program’s name and the page that says so.

Program	Covers a Tempra?	What the source says
LogisVert (Hydro-Québec)	No	The residential guide v1.10 (Sept. 15, 2026) includes no water heater.
ENERGY STAR	No	The Residential Water Heaters v5.0 specification excludes electric resistance water heaters; a Tempra cannot be certified.
Rénoclimat (Québec)	No	The mechanical systems part covers only air exchangers (HRV/ERV) and drain-water heat recovery; no water heater.
Chauffez vert (Québec)	Ended	Aid ended on March 31, 2026.
Canada Greener Homes Grant	Closed	Program closed; it excluded tankless water heaters other than heat pump models.

UL 499

“Conforms to UL Std. 499”: safety standard for electric heating appliances, per Stiebel’s spec sheet.

CAN/CSA C22.2 No. 88

“Certified to CAN/CSA Std. C22.2 No. 88”: the Canadian certification Stiebel lists.

NSF/ANSI/CAN 372

Certified by the WQA for lead-free compliance.

08 · Stiebel Eltron

A German family company since 1924

Stiebel Eltron has built tankless water heaters for decades. In North America, sales and service go through Stiebel Eltron, Inc., in West Hatfield, Massachusetts

1924founded in Berlin by Dr. Theodor Stiebel

Holzmindenhead office, in Germany

Family-ownedowned by the Stiebel family and the Stiebel Familienstiftung

“Made in Germany”Stiebel’s statement on its Tempra pages

What Stiebel claims

According to Stiebel Eltron, the Tempra reaches “99% efficiency” (published UEF: 0.96 to 0.98), and an electric tankless water heater typically uses 15 to 20% less energy than an electric tank, because it has no standby loss. These are the maker’s figures: we quote them, we did not measure them.

Every Tempra has copper heating chambers and a microprocessor with several temperature and flow sensors, per Stiebel.

Inside view of a Stiebel Eltron Tempra tankless water heater

Full catalogue and comparison tool BLACK+DECKER tankless water heaters GIANT water heaters

09 · Frequently asked questions

The questions people ask us about the Tempra

Type a word (shower, 208, warranty, rebate…) to filter the answers.

Search the FAQ

No answer matches. Call us at 514 316-2973.

Which Tempra for a house with two bathrooms?

It depends on what runs at the same time and on the incoming water. Two 1.5 gpm showers with 42 °F (5.6 °C) water need 27.7 kW: the Tempra 29 (28.8 kW) is enough at 240 V, the Tempra 24 is not. With 52 °F (11.1 °C) water, the Tempra 24 is enough. The tool in section 02 does the math.

Is my 100 A service enough?

Stiebel recommends 100 A for the Tempra 15, 125 A for the 20, 150 A for the 24, 200 A for the 29 and 300 A for the 36, “depending on total electric load at the installation site”. Only a load calculation by a master electrician confirms it.

What is the difference between Trend and Plus?

The Plus adds Advanced Flow Control: if demand exceeds power, it cuts the flow to keep the water at the set temperature. Both self-modulate, have a digital display and can cap hot water at 109 °F (42.8 °C).

Why does the Tempra 15 give 14.4 kW?

The number in the name is a model designation. Stiebel’s spec sheet (rev. 6.2025) gives 14.4 kW at 240 V for the Tempra 15, 19.2 kW for the 20 and 28.8 kW for the 29. The 24 and 36 do give 24 and 36 kW.

What happens at 208 V?

Power drops: for example 18 kW instead of 24 kW for a Tempra 24. Stiebel advises going one model up at 208 V.

Is there a rebate for a Tempra?

No, not in 2026. LogisVert covers no water heater, ENERGY STAR excludes electric resistance water heaters, Chauffez vert ended on March 31, 2026 and the federal grant is closed.

Who can install a tankless water heater?

Stiebel requires a licensed electrician and plumber. In Québec, the electrical hookup falls under subclass 16 (AirGreen holds it) and the water hookup under subclass 15.5 (AirGreen does not hold it).

How long is the warranty?

Seven years against leaks due to a defect and three years against defects in materials or workmanship, from purchase. Labour is not covered. The manual asks you to register the unit within 90 days.

Does it need a relief valve?

Stiebel does not require one for the Tempra. If the inspector asks for one, it goes on the hot water outlet. A pressure-reducing valve is required if pressure exceeds 150 psi.

What if my water is hard?

Per Stiebel, the unit may need descaling every 6 to 12 months, depending on hardness. Damage from scale or corrosive water is excluded from the warranty.

What flow does it need to start?

0.50 gpm for the Tempra 15, 20 and 24, and 0.77 gpm for the Tempra 29 and 36, per Stiebel’s spec sheet.

What water temperature can it deliver?

The setpoint ranges from 68 to 140 °F (20 to 60 °C). A high limit shuts the unit off at 185 °F (85 °C). At showers and tubs, the Code limits water to 49 °C (120 °F) at the outlet.

Your project