An off the shelf ceramic heater is gutted and put in place of the existing vehicle heater core. May have difficulty fitting it into the existing heater box. Will typically draw 13A and 128V.

Pros: instant heat, inexpensive solution

Cons: have to modify the heater box for ceramic element. Have to modify temp controls to be electrical. May get very hot and melt plastic (may require a temp control)

Professional Electric Heater

Randy at CANEV sells a professional quality electric heater which can be installed in place of the existing heater core. Unlike with the inexpensive off the shelf ceramic heaters, these units work well, and have not caused any problems with melting, etc. These have been installed on hundreds of vehicles with great success. One of the most popular alternatives.

Here are a number of installations:

Ryan's 200SX EV Conversion

Ken Norwick's Amazing EV Conversion Supersite (1)

Ken Norwick's Amazing EV Conversion Supersite (2)

Bill Dennis' EV Conversion

Pros: instant heat, moderately priced solution

Cons: have to modify the heater box for heating element. Have to modify temp controls to be electrical.

Electric water heater/pump

An electric water heater/pump will heat water and circulate it through the existing vehicle heater/defrost system. See Metric Mind EV Heater for an example.

Pros: uses existing ICE heater and core, relatively easy to install

Cons: warm up time is slow (2-5 mins). Smaller units may not generate enough heat. Have to modify temp controls to be electrical. Costs about $400,

Use the heat from motor and controller

The motor and controller are too efficient to generate enough heat for the cabin. If the motor/controller is 80% efficient and the drive takes 10kW to go on a flat road, then the excess heat is approx 2kW. 2Kw is not enough to heat 2-3 litres of coolant, plus the controller and motor.

Fuel-Fired Heater

These heaters use kerosene or gasoline as fuel to generate heat. Espar (www.espar.com) or Webasto fuel fired heater make units which can tie into the existing cooling system and use the existing heater core. Although these units use fossil fuel, they put out a lot of heat, which can be useful in very cold climates.

Automotive Block Heater and Water Pump

A 240v 10litre/min pump combined with two 120v 1500w block heaters in series. This can be plumbed into the existing system. To control the temp, cycle the voltage to the block heaters with a control circuit. (How do I leverage using only a 120v pump?)

Peltier Cooler in Reverse

Use peltier coolers in reverse. Might be more efficient than a resistance heater, as you are moving heat plus getting it's inefficiency heat.

Seat Heaters

In addition to other heating methods, seat heaters may be desirable. See various commercial seat heaters.

Infrared lamps

Use Infrared light bulbs to heat a person's body. Depending on the type of IR bulb used, it may not work to defrost a windshield, experiments need to be done.

Heated Windshield

A special windshield has fine wires to electrically defrost.

Selection Criteria

Here are some things to consider when selecting a solution for cabin heating:

Cost to construct
Time to construct
Ability to integrate with existing parts
Durability
Electrical Safety
Effectiveness at heating and defrosting
High efficiency (low power consumption)
Environmentally friendly
Weight
Complexity
Extra space required

Selection for the New Beetle EV Project

At first a 3000 Watt MES Fluid Heater/Pump was going to be installed, as it is the easiest option to install. However, it turns out that most of the dash is removed anyways, exposing the heating unit. Therefore PCT electric heater is going to be installed.

The reasons why:

Does not require any extra space
The fastest warm up time
Very popular solution
Moderately inexpensive

The downsides are:

Requires removing the heater control box (for an integrated solution)

References

1500 Watt-hours = 5120 BTU of energy
Heat capacity of water is 4190 J/(kg degK)
Comparison of cabin heaters

Calculate Power Required to Heat a Room

The following chart shows the amount of power required to heat various sizes of rooms based upon an indoor temperature of 70 DEG degrees F and outside temp of 0 DEG F. In the diagram assume your car is considered as line "D", which is basically an un insulated "shed".

>Room Heating Requirements - Quick Estimate

Calculating Time to Heat Water

Question: how long does it take a 3000W heater to heat 3 litres of water (the approx amount for the MES RM4 fluid heater and coolant lines) from 10 deg C to 90 deg C?

From the thermodynamics formulas:

Energy = Water heat capacity * mass * increase in heat

And Energy = Power * time

rearrange to solve for time t:

t = (C M DT) / P

Insert our values:

t = (4190 J/(kg degK) * 3kg * 80 degK ) / 3000 W

t = 335 seconds (approx 5-6 mins)

NOTE: There are many factors which influence the warm up time of a fluid heater, and your heating enjoyment:

the heater will consume its full rated amount (3000w for the MES fluid heater).
if the pump turns on before it is up to temp, it will take longer to warm up.
the turn-on temperature of the thermostat in the fluid heater may be much cooler than the removed ICE heater (for the MES it is 85^oC)
these calculations do not take into account how long it will take to heat the surrounding pump, hoses or other material.