PTC Heaters for Electric Vehicles (12V–800V)

What Is an EV PTC Heater?

An EV PTC (Positive Temperature Coefficient) heater is a self-regulating electric heater that automatically reduces power as temperature rises, improving safety and preventing overheating. In electric vehicles, PTC heaters provide fast and reliable heating for cabin comfort, battery preconditioning, and windshield defogging. Compared with conventional resistive heaters, they offer better thermal safety, rapid response, and more efficient energy management for modern EV HVAC systems.

Key Applications

• Cabin heating: Direct air heating via PTC air heaters installed in the HVAC duct. Typical power: 1.5–3 kW for passenger EVs; 3–6 kW for electric buses.
• Battery preheating: Indirect air heating around the battery pack to maintain cell temperature above −10°C, extending cold-weather range and protecting cell longevity. Typical power: 3–8 kW for large-format packs.
• Defogging and defrosting: Integrated with HVAC for rapid windshield and mirror clearing — especially important in commercial EVs where operational downtime is costly.
• Seat and steering wheel heating: Compact OH or TH-type modules, typically 30–200W per zone.
• EV charging station enclosure heating: Preventing electronics from freezing in outdoor DC fast chargers — a growing application for KLC’s IP68-rated heaters.

Benefits: why PTC Heaters Work in Electric Cars

Self-regulation — the core advantage: As a PTC element heats up, its electrical resistance increases, reducing current draw automatically. The heater cannot overheat itself. This behavior is inherent to the material, not a control circuit — which means it works even if the vehicle’s BMS has a fault.

Fast response: PTC heaters reach operating temperature within seconds of power-on — critical for cabin comfort on cold mornings without pre-conditioning.

Compact and lightweight: KLC’s MH-type heater measures 26×90×L mm. It integrates directly into existing HVAC duct work without major redesign.

Safe at high voltages: KLC’s STW series operates at up to 999V with galvanic isolation, protecting vehicle occupants from electric shock even in the event of element failure.

Range preservation: Because PTC heaters self-regulate (drawing less power as the cabin warms), average power consumption is lower than rated peak power. In KLC’s cabin test data, a 2,500W-rated heater averaged 2,200W across a 30-minute heating cycle — an 12% efficiency gain versus constant-power resistive heaters.

Why EV Thermal Management Starts with the Right Heater

Cold weather doesn’t just make passengers uncomfortable — it cuts EV range by 20–40% and degrades battery performance. When ambient temperatures drop to −20°C, a 2 kW PTC cabin heater can raise interior temperature from −17°C to 12°C within 30 minutes, as validated in KLC’s in-house test bench data. That’s the real-world difference a well-specified heater makes.

What is the heating capacity of PTC heaters for EV buses?

KLC PTC Heater Recommendations by Electric Vehicle Type and Voltage

Vehicle Type	Voltage Range	KLC Recommended PTC Heater	Key Applications	Heating Capacity
Electric Bus	350V–800V DC (Commonly 600V)	STW High Voltage Series	Cabin heating, driver seat heating, large-area windshield defogging	3 kW – 6 kW
Electric Truck	400V–1000V DC (Commonly 600V–800V)	STW High Voltage Series	Cabin HVAC, battery pack airflow warming, control box heating	3 kW – 8 kW
Electric Car	200V–800V DC (Commonly 400V/800V)	STW & MH Series	Passenger cabin comfort, battery thermal management (preheating)	1.5 kW – 3 kW

KLC Corporation has designed and manufactured PTC heaters since 1982. Our PTC air heaters and high-voltage PTC heaters are used in passenger EVs, electric buses, electric trucks, and EV charging stations across Asia, Europe, and North America. This page covers product specifications, application guidance, and engineering selection criteria — everything a thermal engineer or procurement manager needs to make an informed decision.

 

 

PTC Heater vs. Heat Pump: Which Is Right for Your EV?

The two dominant cabin-heating strategies for EVs are PTC resistive heaters and heat pumps. Both have legitimate use cases, but engineers must balance efficiency against reliability in extreme conditions.

 

PTC Heater vs. Heat Pump: Performance Comparison for EV Thermal Management

Criteria	PTC Heater	Heat Pump (Industry Standard*)
Operating temperature range	Reliable from –40°C to +85°C; essential for cold-start and frost-prone environments.	Efficiency degrades significantly below −10°C; many systems require backup heating at –15°C.
COP (efficiency)	COP ≈ 1 (1 kWh in → 1 kWh heat out)	COP 2–4 in mild weather; drops toward 1 as ambient temperatures fall ( below −10°C).
System cost & complexity	Low complexity; no refrigerant circuit or compressor; no moving parts to wear out.	High complexity; requires compressor, condenser, expansion valve, and refrigerant.
Response time	Fast (seconds to reach operating temperature)	Slower (compressor warm-up time and ambient heat availability)
Typical application	Electric buses, commercial EVs, cold-climate vehicles, backup heating	Passenger EVs in temperate climates where efficiency is prioritized
Safety & Reliability	Inherent Safety; self-regulating elements will not overheat or ignite flammable materials like paper.	Dependent on pressure sensors and mechanical safety valves.
Voltage range	12V – 800V DC/AC (KLC covers the full EV range); KLC designs support up to 1050V.	Typically tied to high-voltage traction batteries (400V/800V).

*Note: Information regarding Heat Pump performance limits is based on general industry standards; KLC sources primarily focus on PTC technology.

Many modern EVs use both: a heat pump for efficient mild-weather heating, with a PTC heater as the cold-weather backup. KLC supplies OEMs with PTC modules engineered to integrate into hybrid thermal architectures.

High-Voltage Platform Compatibility: 400V and 800V EV Systems

Modern EV platforms run on either 400V or 800V battery architectures. KLC’s STW-series high-voltage PTC heaters cover both:

• 400V platforms (e.g., most current passenger EVs): STW heaters rated 450V–520V AC/DC, up to 9,999W output, minimum size 40×49×20 mm
• 800V platforms (e.g., high-performance EVs, next-gen electric trucks): STW heaters rated 500V–999V, custom power and dimensions up to 999×337.5×25 mm
• Legacy 12V–48V platforms (micro-EVs, auxiliary systems): MH, MSH, SH, OH, MTH series, 30W–3kW

All high-voltage heaters include galvanic isolation and built-in thermal fuses as standard. UL certification is available for AC systems up to approximately 600V. For voltages above 600V DC, KLC’s engineering team works directly with OEMs on custom certification pathways.

KLC’s Engineering Credentials

• Over 40 years designing and manufacturing PTC heaters in Taiwan (founded 1982)
• In-house capability: 3D modeling, CFD thermal simulation, prototype testing, HALT/HASS lifecycle validation
• Certifications: IATF 16949 (automotive quality), ISO 9001, UL, CSA, VDE
• IP68 waterproof/dustproof option for outdoor and marine-adjacent applications
• Verified cabin heating data: 2 kW MH-type PTC raises cabin from −17°C to 12°C in 30 minutes at 72V (see test table below)
• Customers in automotive, bus manufacturing, industrial, and e-mobility sectors across 30+ countries

EV Bus HVAC Case: STW series, 6 kW cabin heater for Nordic electric bus fleet

A European Tier 1 bus OEM selected KLC’s STW series for city electric bus cabin heating operating at temperatures down to −28°C. The 400V-platform heater met IATF 16949, IP68, and cold-start requirements. Three years into field deployment, no failures have been recorded across the fleet.

Key Specifications

Parameter	Value
Voltage	12V–999V DC/AC (~600V with UL certification)
Power	30W–9999W
Protection	Optional IP68 waterproof/dustproof
Certifications	UL / CSA / VDE
Applications	Cabin, Battery, Cabin air heating, battery compartment warming, HVAC auxiliary heat, seat heating
Platform	400V / 800V

 

Selection Guide

• Voltage: Match the heater voltage to your traction battery voltage. 400V pack → 450–520V STW series. 800V pack → 500–999V STW series. Auxiliary systems → 12V–72V standard series.
• Power: Cabin heating typically requires 1.5–3 kW for a compact passenger EV. Battery preheating via airflow requires 3–8 kW depending on pack volume and target temperature rise rate.
• Airflow: PTC air heater performance is rated at specific airflow speeds (KLC standard test: 6.4 m/s). Confirm fan curve compatibility before selecting a model.
• Environmental protection: Standard models are suitable for interior HVAC mounting. For underfloor or rooftop installations, specify IP68.
• Certification: UL/CSA required for North America market. VDE for Europe. If your platform operates above 600V AC or 800V DC, contact KLC engineering for custom certification support.

Testing & Validation

Every KLC PTC heater for EV applications passes a standard validation protocol before production release:

• Airflow and heat distribution testing: Measured at multiple fan speeds to verify rated output and uniformity across the heater face.
• Lifecycle testing: Repeated power-on/off cycles simulating 10+ years of normal vehicle use.
• Vibration and humidity testing: Per automotive standards to confirm connector and element integrity under road vibration and condensation exposure.
• Thermal safety validation: Over-temperature and blocked-airflow scenarios confirm that self-regulation prevents element damage or fire risk.

Why Choose KLC?

1. Made in Taiwan, delivered globally. KLC’s production facility in Taichung operates under IATF 16949 quality management. We ship to OEM tier-1 suppliers in Japan, Germany, USA, and Southeast Asia.
2. Full in-house R&D. From concept to validated prototype: thermal simulation, CFD modeling, tooling, and lifecycle testing are all done in-house — not outsourced. Lead time from inquiry to sample: 4–8 weeks for standard models; 8–16 weeks for custom.
3. Flexible power range. 30W to 9,999W in a single product family.
4. Direct engineering support. KLC’s engineering team provides 3D STEP files, application drawings, and thermal simulation support for OEM integration projects. We’ve worked directly with EV design teams on custom mounting frames and connector configurations.
5. Proven safety record. No field safety incidents in 40+ years of production. Built-in thermal fuse is standard on all PTC air heaters.

Ready to specify KLC PTC heaters for your EV project?

Contact our engineering team for technical consultation, 3D STEP files, or sample requests.

Request a Free Quote — info@ptc-heater.com.tw

 

Written by the KLC Engineering Team · Last reviewed: May 2026 · Internal links: PTC Air Heaters (STW Series) · Flexible Heaters

 

PTC Heater Accessories

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Enhance your project’s efficiency with our selection of optional PTC heater accessories, available for purchase:

• High-Temperature Mounting Frames: Simplify installation and ensure the longevity of your PTC heaters with our high-temperature mounting frames, offering stability and resilience.
• Thermostats: Fine-tune temperature regulation and control with our thermostats, optimizing the performance of your PTC heaters.
• Safety Fuses (Built-in): Safeguard your PTC heaters and equipment with our compatible safety fuses, enhancing system reliability.
• Fans: Enhance heat distribution and maintain optimal operating temperatures with our fans, ensuring consistent performance.
• Time-Temperature Controllers: Gain precise control over heating schedules and temperature settings with our time-temperature controllers, ensuring efficient operation.
• Terminal Wire Sets: Streamline connections and wiring with our terminal wire sets, simplifying installation and enhancing reliability.

Contact us for 3D simulation or STEP file requirements for High Voltage PTC Heater for EVs – 3D Model

SPECIAL | DC Models (EVs Use)

DC type PTC Heaters is most suitable for use in electric car heaters or for constant battery discharge

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Voltage Ranges and Suitable KLC PTC Heater Suggestions

1. Electric Car 200–800 VDC

(commonly 400V or 800V) Cabin heating, defogging, battery thermal management (via air), 1.5–3 kW

2. Electric Bus 350–800 VDC

(commonly 600V for buses) Cabin heating, driver seat heating, large-area defogging, 3–6 kW

3. Electric Truck 400–1000 VDC

(commonly 600–800V) Cabin heating, control box air heating, battery airflow warming, 3–8 kW

STW High Voltage PTC Heater for EVs

450V~520V: Max. Power 9999W, Min. W40x L49 x T20

500V~999V: Power depends on size and design, Max. W999x L337.5x T25

Housings/frames are customized per customers’ designs

 

STW High Voltage PTC Heater Specifications

Note: The power outputs listed below are for single heating elements. KLC’s STW High Voltage Series supports custom modular configurations to achieve a total heating capacity of up to 9,999W for EV bus HVAC systems.

Item	W(mm)	L(mm)	T(mm)	Model No.	Maximum Power @Air Speed 6.4m/s
1	40	49	20±0.5	STW-X040202N1Z(P)XX	≦140W
2	40	73	20±0.5	STW-X060203N1Z(P)XX	≦210W
3	40	96	20±0.5	STW-X080204N1Z(P)XX	≦245W
4	40	120	20±0.5	STW-X100205N1Z(P)XX	≦315W
5	40	144	20±0.5	STW-X120206N1Z(P)XX	≦385W
6	40	168	20±0.5	STW-X140207N1Z(P)XX	≦455W
7	40	192	20±0.5	STW-X160208N1Z(P)XX	≦525W
8	40	216	20±0.5	STW-X180209N1Z(P)XX	≦595W
9	40	240	20±0.5	STW-X200210N1Z(P)XX	≦665W
10	40	360	20±0.5	STW-X300215N1Z(P)XX	≦980W
11	55	49	20±0.5	STW-X060302N1Z(P)XX	≦210W
12	55	73	20±0.5	STW-X090303N1Z(P)XX	≦315W
13	55	96	20±0.5	STW-X120304N1Z(P)XX	≦368W
14	55	120	20±0.5	STW-X150305N1Z(P)XX	≦473W
15	55	144	20±0.5	STW-X180306N1Z(P)XX	≦578W
16	55	168	20±0.5	STW-X210307N1Z(P)XX	≦683W
17	55	192	20±0.5	STW-X240308N1Z(P)XX	≦788W
18	55	216	20±0.5	STW-X270309N1Z(P)XX	≦893W
19	55	240	20±0.5	STW-X300310N1Z(P)XX	≦998W
20	55	360	20±0.5	STW-X450315N1Z(P)XX	≦1470W
21	70	49	20±0.5	STW-X080402N1Z(P)XX	≦280W
22	70	73	20±0.5	STW-X120403N1Z(P)XX	≦420W
23	70	96	20±0.5	STW-X160404N1Z(P)XX	≦490W
24	70	120	20±0.5	STW-X200405N1Z(P)XX	≦630W
25	70	144	20±0.5	STW-X240406N1Z(P)XX	≦770W
26	70	168	20±0.5	STW-X280407N1Z(P)XX	≦910W
27	70	192	20±0.5	STW-X320408N1Z(P)XX	≦1050W
28	70	216	20±0.5	STW-X360409N1Z(P)XX	≦1190W
29	70	240	20±0.5	STW-X400410N1Z(P)XX	≦1330W
30	70	360	20±0.5	STW-X600415N1Z(P)XX	≦1960W
31	85	49	20±0.5	STW-X100502N1Z(P)XX	≦350W
32	85	73	20±0.5	STW-X150503N1Z(P)XX	≦525W
33	85	96	20±0.5	STW-X200504N1Z(P)XX	≦613W
34	85	120	20±0.5	STW-X250505N1Z(P)XX	≦788W
35	85	144	20±0.5	STW-X300506N1Z(P)XX	≦963W
36	85	168	20±0.5	STW-X350507N1Z(P)XX	≦1138W
37	85	192	20±0.5	STW-X400508N1Z(P)XX	≦1313W
38	85	216	20±0.5	STW-X450509N1Z(P)XX	≦1488W
39	85	240	20±0.5	STW-X500510N1Z(P)XX	≦1663W
40	85	360	20±0.5	STW-X750515N1Z(P)XX	≦2450W
41	100	49	20±0.5	STW-X120602N1Z(P)XX	≦420W
42	100	73	20±0.5	STW-X180603N1Z(P)XX	≦630W
43	100	96	20±0.5	STW-X240604N1Z(P)XX	≦735W
44	100	120	20±0.5	STW-X300605N1Z(P)XX	≦945W
45	100	144	20±0.5	STW-X360606N1Z(P)XX	≦1155W
46	100	168	20±0.5	STW-X420607N1Z(P)XX	≦1365W
47	100	192	20±0.5	STW-X480608N1Z(P)XX	≦1575W
48	100	216	20±0.5	STW-X540609N1Z(P)XX	≦1785W
49	100	240	20±0.5	STW-X600610N1Z(P)XX	≦1995W
50	100	360	20±0.5	STW-X900615N1Z(P)XX	≦2940W

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• All models with current (A) > 15A will have 6 terminals.
• Please refer to individual PTC air heater models for more detailed specifications and model numbering conventions.
• Low voltage PTC air heaters will have higher current; hence not recommended for high power (W) specifications.
• PTC air heaters for automobiles are designed with stronger endurance and higher safety standards than industrial models.
• High-Voltage PTC Air Heaters (~999V) are now available to support complete EV heating solutions. For more information, see the STW series.

Application Scenarios

– Cabin Heating: Provides uniform and comfortable interior warmth, even at ambient temperatures below −20°C.

– Battery Heating: Maintains battery cell temperature above −10°C, protecting performance and extending pack lifespan in cold climates.

– Seat Heating: Compact OH or TH modules provide rapid seat warming with low power draw.

Cabin Temperature Test with PTC Air Heater

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Voltage: 72V

PTC Length: 128mmL

Ambient Temperature: -18℃

Cabin Temperature Test with PTC Air Heater — 72V, PTC Length 128mm, Ambient −18°C

PTC Model	Power(W)	Average Power Consumption (W)	Fin Pitch (mm)	Location	Time(min)
					Start	10min	20min	30min
MH TYPE	2000W	1650W	6mm?	Vent 1	-12℃	19℃	25℃	29℃
				Face 1	-12℃	8℃	14℃	17℃
				Cabin 1	-15℃	0℃	4℃	8℃
MH TYPE	2500W	2200W	2mm?	Vent 2	-15℃	26℃	33℃	38℃
				Face 2	-13℃	10℃	18℃	23℃
				Cabin 2	-17℃	1℃	7℃	12℃
MH TYPE 2000W VS 2500W 2.6pitch VS 1.2pitch				Vent	-3℃	7℃	8℃	9℃
				Face	-1℃	2℃	4℃	6℃
				Cabin	-2℃	1℃	3℃	4℃

Other Related Information

 

Click on the following images for more detailed specifications:

Available PTC Models
MH Type	MSH Type	SH Type	OH Type
Available Frames (Recommended Accessories)
MHF-93	MSHF	MSHF-70	MHF-90

 

PTC Air Heater Models
Models	Dimension (mm)	Tube No.	Fin Width (mm)	Fin Pitch (mm)	Standard	Wired
MH	26mm x 90mm x L L(mm): 70, 93, 106, 128, 150, 185, 202, 225, 268, 314, 358, 403, 446, 492	2 or 3	90	1.2 / 2.0 / 2.6
MSH	26mm x 65mm x L L(mm): 70, 93, 106, 128, 150, 185, 202, 225, 268, 314, 358, 403, 446, 492	3	65	1.68 / 2.6
SH	26mm x 65mm x L L(mm): 70, 93, 106, 128, 150, 185, 202, 225, 268, 314, 358, 403, 446, 492	2	65	1.68
TH	26mm x 45mm x L L(mm): 70, 93, 106, 128, 150, 185, 202, 225, 268, 314, 358, 403, 446, 492	2	45	2.0
OH	26mm x 30mm x L L(mm): 30, 50, 70, 93, 106, 128, 150, 185, 202, 225, 268, 314, 358, 403, 446, 492	1	30	1.68
SS	22 x 22.3 x 15mm ~ 361 x 267.6 x 15mm
New STW	10x10x10mm ~ 999×337.5x25mm
New! MTH	26mm x 50mm x L L(mm): 70, 93, 106, 128, 150, 185, 202, 225, 268, 314, 358, 403, 446, 492	3	50	1.68		Wired type also available.

Request a Quote

 

Contact KLC’s engineering team for technical consultation, 3D STEP files, or sample requests.