iMiEV Heater Installation


Overall, I love my little electric car, the Mitsubishi iMiEV. It’s a good, affordable, all electric commuter car.

It’s one shortcoming is that it was never designed for COLD Wisconsin winters. The heater is electric (of course!) but it heats a liquid antifreeze (coolant) which then circulates through a heater core, where a fan finally blows the heat into the car. It’s not particularly efficient and has a bit of a warm-up time. On top of that, the system only heats the coolant to around 140 degrees Fahrenheit. Most typical gas cars keep the engine coolant at 190 degrees once they are at temperature!

1453064184742The car also has the smallest battery pack of any commercially-available battery-electric car in the United States. Combine a small battery pack with an inefficient heater, and a Wisconsin winter, and it becomes a recipe for short range and a cold driver. In this screen grab, red shows energy used by the heater, and blue shows energy used to push the car down the road. When it’s really cold, range can be shortened by a third or more!

So, after reading lots of information about “Winterizing” these cars on the MyiMiEV forum, I decided to install a dedicated fuel-burning heater. The heater I chose was one already used by several of those forum members. It’s a generic version of an Espar 5kW liquid heater. My heater was roughly $500 and was purchased through You can also find the heater through the manufacturer’s web page.┬áIt’s the 5kW 12V Gasoline version.

IMG_7626So, far, I’m running the heater on E85 from my local gas station. I have a friend who makes his own ethanol from scratch, and I intend to get some pure, sustainably produced ethanol from him. Even with the heater running full blast, fuel use translates into hundreds of miles per gallon.

Mounting the heater in parallel with the original electric heating system allows me to use the electric OR liquid-fueled heater, and I can still use the car’s electric “pre-heat” feature. I intend to use the fuel burner when it’s either very cold, or when I have concerns about range, due to the electric heater otherwise sapping power.

In effect, what I am doing is using a liquid fuel for heating, to maximize battery energy for propulsion – trying to “use the right tool for the right job”!

After the heater arrived in the mail, I first rigged it up on a stand in my garage to learn what I needed to do to hook it up and test it. I also shot some thermal video of the heater running hot water into a bucket as an initial test.

Once I had a basic understanding of the heater, I started the process of the actual installation of the heater into the car.

What follows is a series of 6 videos showing step by step how I installed this heater in the car.

A big Thank You to other Mitsubishi iMiEV owners who have shared information on modifying the heater systems in their cars! I hope these videos help anyone else who is interested in hybridizing their heating system in cold climates!

I’ll add some more information here as I get more experience using this heater!

-Ben Nelson

{ 1 trackback }

Electric Car Heater Thermal Imaging
February 16, 2016 at 11:33 am

{ 11 comments… read them below or add one }

1 John Gordon September 3, 2016 at 11:20 am

do the original electric heater controls work with both systems?
Thanks meantime,

2 BenN September 3, 2016 at 12:24 pm

The original electric heater control is completely unmodified, and works exactly as intended at any time. For the auxiliary system that I installed, it’s turned on and off with a very small control panel that was included, otherwise, it just uses the original existing controls for blower speed and where the heat is being directed. To use the auxiliary system only, I just set the temperature control on the car to neutral (neither hot or cold.) That makes sure that the electric heater does NOT come on, but that air is still being routed past the heat exchanger.

3 John Gordon September 4, 2016 at 10:02 am

I know you use a petrol heater but is the comment below relevant?
Thanks for your quick reply.
Just beware that the diesel heaters should have more than 3 liters to work optimal. With only 2 liters the heater will have very short heating intervals. This may cause the heater to burn less clean, use more fuel, and needing service more often. You might want to add a small tank.

4 BenN September 4, 2016 at 11:07 am

I can’t think of any reason why the size of the fuel tank would effect “How Clean” the heater burns fuel. If the tank was SO TINY that the heater could only run for a few minutes, that would be one thing, but even with this very small tank, the heater can run for hours. One upside of a slightly smaller tank would just be to top off the fuel less often.

5 John Gordon September 4, 2016 at 12:16 pm

This comment was for the amount of water ( Antifreeze mix ) in the original heating system.
Thanks again,

6 BenN September 8, 2016 at 9:27 am

This car does have a rather small antifreeze/coolant tank. However, there isn’t an issue with the heater cycling on and off. Typically, I’m just running the heat full blast. The heat is pulled out fast enough from the coolant that the heater doesn’t shut off from the coolant getting too hot.
One advantage of having MORE coolant would be that more could be heated up using the “Pre-Heat” feature of the car.
So far, the aftermarket “Parking Heater” has worked very well, and is a really nice addition to the vehicle.

7 John Gordon October 28, 2016 at 9:33 am

Hi Again,
My heater has now arrived but it has an external water pump this I assume is not required.
Thanks again,

8 admin October 28, 2016 at 10:22 am

Hi John, it would depend on your exact model heater. My fossil-fuel heater has a pump built right into it, which circulates the heated water into the existing heater system of the car. You may have a model of heater WITHOUT an internal pump. In that case, it may require an external pump.

9 John Gordon October 29, 2016 at 4:50 am

Please see above I bought the Petrol version and they said it was the same heater you used.

10 admin October 29, 2016 at 9:00 am

Hi John, I took a look at the PDF. On the first page that shows all the parts of the heater labeled, item #13 is the internal water pump. So, it appears that you have the same heater. I don’t know why yours also included an external water pump, but you don’t need it for an iMiEV installation.

11 frank Romero November 8, 2016 at 3:45 pm

HI Ben, I watched your videos on adding this heater . Thanks for the info. I just bought a 2013 leaf s. I understand that these have the older heaters from 2012 and older. Only sv and sl have that upgrade. How would I know if that’s true. Any help would be appreciated . I live in the suburbs of Chicago. It gets very cold here also. I didn’t realize you were so close until I saw many of your videos. HI neighbor :)

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