Most first-time EV converters focus on motors and batteries—then realize halfway through the build they have no cabin heat. No engine means no waste heat, and no waste heat means a cold cab in winter. The heater you choose affects not just comfort but range, wiring complexity, and whether your build passes inspection where defrost is mandatory.
Here is how the four main options compare and which one fits your specific build.
Option 1: PTC Air Heaters — Best for Passenger Cars and Small UTVs
PTC (Positive Temperature Coefficient) air heaters use ceramic elements that self-regulate temperature. They cannot overheat even if the fan fails. They mount inside the existing HVAC box or as an inline duct heater and provide instant warm air.
Best for: Sedans, SUVs, light trucks, and enclosed-cab UTVs running 96 V to 400 V battery packs. Low-voltage versions (12 V–72 V) work on golf carts and small farm vehicles.
CMVTE advantage: Our 400 V PTC heaters (5 kW and 7 kW) come with PWM or CAN control and integrate directly with our VCU. No need to hunt down a separate controller or hack together a wiring harness—everything is in one kit.
A DIY builder in the US installed a CMVTE 400 V PTC heater in a classic pickup conversion. The total install time for the heating system was under four hours, and cabin temperature reached 20 °C within three minutes at 0 °C ambient.
Option 2: Coolant-Based Heaters — Best for Vans, Buses, and Large Cabins
These replicate the ICE heater core layout. An electric element warms a closed glycol loop, and a pump circulates hot coolant through the existing heater core. The blower motor, ducts, and vents stay factory.
Best for: Mercedes Sprinter RVs, city buses, delivery vans, and any build where the original HVAC is intact and worth keeping. Farm UTVs with large enclosed cabs also benefit when PTC air heaters cannot keep up.
CMVTE advantage: We supply complete coolant heater kits from 5 kW to 15 kW—heating element, circulation pump, expansion tank, control harness, and overheat protection. Every component is tested as a system before shipment. A 10-meter city bus conversion in Europe runs a CMVTE 12 kW coolant heater integrated with the factory HVAC, meeting passenger transport heating standards.
Option 3: Heat Pumps — Efficient but Complex
Heat pumps move ambient heat into the cabin at 2–3x the efficiency of resistive heaters. They save range in mild climates but lose effectiveness below -10 °C, require a backup heater, and demand a full HVAC redesign. Most DIY converters skip heat pumps unless they are building from a complete blank slate.
Option 4: Diesel Heaters — Backup for Extreme Cold
Diesel-fired air heaters burn 0.2–0.5 L/hour and provide independent heat regardless of battery voltage. They are common in RVs and overland builds. Some farm UTV operators keep a diesel heater as a cold-weather backup and use an electric PTC for daily driving. The trade-off is fuel storage and emissions.
How to Pick the Right Heater
Cabin size: 3–5 kW for a car, 5–8 kW for a van, 10–15 kW for a bus. Oversizing wastes battery capacity; undersizing leaves the cabin cold on winter mornings. Climate: In regions where winter hits -15 °C or below, coolant or diesel backup is the safe bet. PTC air heaters work well in moderate climates for daily-driven vehicles. Voltage: A 400 V PTC draws directly from the main traction pack without loading the 12 V auxiliary system—more efficient and simpler to wire. HVAC state: If the donor heater core and ducts are intact, coolant-based is the path of least resistance. If you are replacing the HVAC anyway, a PTC air heater in the duct saves plumbing.
Why CMVTE Heaters Are Different
CMVTE is not a parts reseller. We manufacture the motor, controller, battery, DC-DC converter, and heater under one roof. That means your heater is designed to work with your drive system—CAN profiles match, voltage ranges align, and the harness plugs in without guesswork.
- 400 V PTC cabin heaters — 5 kW and 7 kW, PWM or CAN control
- High-voltage coolant heaters — 5 kW to 15 kW, with pump and tank
- Low-voltage PTC heaters — 12 V to 72 V, for small EVs and UTVs
- Engineering consultation included with every heater kit
Every kit ships with wiring diagrams, overheat protection, flow detection, and emergency shutoff. No chasing down missing parts.
Contact CMVTE with your vehicle type, voltage, and cabin size for a custom heater recommendation.
