How to Select the Right PTC Heater?

Quick answer:

PTC Heater Selection Process

Voltage → Power → Heat Transfer → Airflow → Dimensions → Insulation & Safety → Application → Standard / Custom

Select a PTC heater by matching four parameters to your application: (1) supply voltage — KLC’s range spans 12V AC/DC up to 999V and Power output — 30W to 10,000W; (2) the Heating Method; (3) Insulation & Safety Requirements (electrically isolated exterior, ~10% lower power, required for automotive/EV and high-humidity environments); (4) Application & Compliance Requirements (UL/CSA/VDE/IP68), based on your operating.

PTC Heater Selection Guide for Engineers

Selecting the right PTC heater (Positive Temperature Coefficient heater) starts with defining the actual application conditions—not just the required wattage.

Follow the steps below to provide the key information needed for KLC to recommend a suitable standard or customized PTC heater.

Step 1. Define Voltage & Power

Provide:

• Operating Voltage: V / AC or DC
• Target Power: W
• Ambient Temperature: °C
• Target Temperature: °C

Important: PTC heater power is dynamic. Actual power depends on voltage, temperature, airflow, and heat dissipation. Power ratings should always be evaluated under defined test conditions.

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Step 2. Define the Heating Method

Air Heating

For HVAC, EV cabin heating, dehumidifiers, heat pumps, and industrial air heating:

Provide:

• Air velocity (m/s) or airflow (CFM / m³/h)
• Air inlet temperature
• Required outlet temperature
• Available installation space

→ PTC Air Heaters

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

 

Conduction Heating

For heating plates, components, or fluids:

Provide:

• Heated object or fluid
• Material / fluid type
• Dimensions and weight
• Contact area
• Target temperature
• Required heating time

→ PTC Heat Conductors

 

Contact Our Engineers to get tailored recommendations for your project.

 

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Step 3. Define Size & Mounting

Provide the maximum available:

L × W × H (mm)

Also specify:

• Mounting method
• Mounting-hole position
• Connector / cable location
• Airflow direction, if applicable
• Required insulation or electrical clearance

If no standard product fits your requirements, KLC can evaluate a custom PTC heater design.

→ [Customized PTC Heater Solutions]

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Step 4. Define Insulation & Safety Requirements

Specify whether the application requires:

• S-Type: Higher thermal efficiency; external fin may carry electrical potential depending on construction.
• D-Type: Electrically insulated external fin surface.

Also provide any requirements for:

• Inrush current
• Thermostat / thermal cutout
• Temperature sensor
• Fuse
• Electrical insulation
• Environmental protection

PTC self-regulation helps limit power as temperature rises, but it should not be considered a replacement for complete system-level thermal protection.

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Step 5. Define Application & Compliance Requirements

Tell us where the heater will be used.

Examples:

• Automotive / EV
• HVAC
• Industrial equipment
• Appliance
• Dehumidifier
• Fluid heating
• Thermal management

If applicable, specify required:

UL / CE / CSA / TÜV / GS / RoHS / REACH / IATF 16949 / OEM requirements

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Step 6. Define Production Requirements

For customized projects, provide:

• Prototype quantity
• Estimated annual usage (EAU)
• Target production date
• Mass-production requirements

This helps KLC determine the appropriate standard product, customization level, manufacturing method, and cost structure.

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KLC PTC Heater Selection Process

Application Requirements
↓
Voltage + Power
↓
Airflow / Heat Transfer
↓
Dimensions + Mounting
↓
Insulation + Safety
↓
Application & Compliance
↓
Standard or Customized PTC Heater
↓
Prototype & Application Validation

 

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Standard PTC Heater or Customized Solution?

Standard PTC Heater

Recommended when your requirements match an existing KLC product in terms of:

• Voltage
• Power
• Dimensions
• Airflow
• Insulation
• Mounting

Customized PTC Heater

Recommended when you require:

• Customized dimensions
• Specific voltage or power
• Special mounting structure
• Customized connector
• Special insulation
• Specific airflow configuration
• Application-specific performance

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Need Help Selecting the Right PTC Heater?

You do not need to have every specification finalized before contacting KLC.

Send us your available:

Voltage + Power + Application + Airflow + Dimensions

and our engineers can help determine the appropriate PTC heater configuration.

Request a PTC Heater Recommendation

Request a Quote

 

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Model	Dimensions (W×T×L, mm)	Standard L (mm)	Tube No.	Fin Width (mm)	Fin Pitch (mm)	Wired Available
MH	90 × 26 × L	70, 93, 106, 128, 150, 180, 202 (special: up to 492)	2 or 3	90	1.2 / 2.0 / 2.6	Yes (MHW)
MSH	65 × 26 × L	70–202 (special: up to 492)	3	65	1.68 / 2.6	Yes (MSHW)
SH	65 × 26 × L	70–202 (special: up to 492)	2	65	1.68	Yes (SHW)
DH	50 × 26 × L	70–202 (special: up to 492)	2	50	1.68	Yes (DHW)
TH	45 × 26 × L	70–202 (special: up to 492)	2	45	2.0	Yes (THW)
OH	30 × 26 × L	30, 40, 70–202 (special: up to 492)	1	30	1.68	Yes (OHW)
SS	22 × 22.3 × 15 up to 361 × 267.6 × 15	–	–	–	–	–
STW (high voltage)	10 × 10 × 10 up to 999 × 337.5 × 25	–	–	–	–	Yes

Dimensions and specifications may be changed without prior notice. SS and STW are flat/high-voltage variants; STW supports the full 999V high-voltage range.

Wired vs. Non-Wired PTC Models — Comparison

Attribute	Non-Wired (Standard)	Wired (New)
Power input	Positive (+) and negative (–) on either side	Single-sided positive (+) and negative (–)
Wiring	Requires wires with female terminals	Connects directly to power
Standard frames	Available	Available
Accessories & wiring	Available (single-stage / multi-stage power setting)	Requires customization
Current / power limitation	None	≤ 15A; ≤ 1,800W
Best suited for	Applications where power connection isn’t restricted to a single side; broad heating scope	Automotive (better vibration endurance, reduced terminal-oxidation risk); optional silicone seal for high-humidity use

 

→ Designing for EV thermal management? See PTC Heaters for Electric Vehicles (12V–800V).

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Accessories & Frames

For full technical data on Full Claded PTC air heaters, contact our engineers.

Available Frames (Recommended Accessories)
MHF-93	MSHF	MSHF-70	MHF-90

 

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Frequently Asked Questions

What voltage range do KLC PTC heaters support?

12V AC/DC up to 999V, with standard bands of 100V–120V and 200V–240V. Other voltage ranges are available on request.

Why does a PTC heater’s power drop when there’s no airflow?

PTC ceramic is self-regulating. As airflow decreases, the surface temperature rises toward the material’s Curie temperature, resistance increases sharply, and power draw falls — at zero airflow, power can drop to roughly 1/20 of the rated value at 6.4 m/s air speed. This is a built-in safety behavior, not a malfunction.

What’s the difference between single- and double-insulated PTC heaters?

Single-insulated (standard) heaters have exposed fins that carry input voltage. Double-insulated heaters fully isolate the heating element inside the aluminum tube, electrically insulating the entire exterior — at the cost of ~10% lower power output and 15–30% higher price. Double insulation is standard for automotive, EV, and high-humidity applications.

When should I choose Wired vs. Non-Wired?

Choose Wired when the power connection is fixed to one side and vibration resistance matters (e.g., automotive) — it connects directly to power and reduces terminal-oxidation risk, but is limited to ≤15A/≤1,800W. Choose Non-Wired for broader application flexibility with no current/power limitation.

How does fin pitch affect PTC heater performance?

Narrower fin pitch (1.2mm/1.68mm) maximizes heat output and outlet temperature but increases airflow resistance and noise. Wider fin pitch (2.0mm/2.6mm) reduces output by 5–10% but lowers airflow resistance and noise.