Programmatically defrost car windows?

Question

It would be most convenient to find a way to defrost car windows programmically (using a timer and switch).

Remote starts don't seem to have the functionality to programmatically schedule a start schedule and fall short for the following reasons:

1. Affordability - initial product, installation and potentially monthly costs for data service devices, aren't quite worth it for me.
2. System wear and tear - warming up the engine in idle, at least the most common combustion engines, doesn't seem to be too good for the engine.

Currently, it seems all of the conventional products on the market, i.e. Peak® Programmable Defroster / Heater, are poorly rated, an there don't seem to be any series of parallel linear resistive conductors products to place on the inside of the window surface.

In concept, it seems better to run an outdoor extension cord into the vehicle that powers a timer/switch that has a battery backup, connecting a heat pad strapped to a sturdy shade reflector, or perhaps a space heater.

In an average car, mine is a '01 Altima, is there an ideal location to run either a flat or regular outdoor extension cord into the vehicle? Perhaps there is a hole or an air gap crevice in the bottom of the car, perhaps near the trunk?

Answer 1

The most convenient solutions are an electric engine block heater (as @mikes mentioned) or a petrol/diesel powered stationary heater. The latter is expensive, but generally more powerful than a block heater.

Putting a space heater inside the car interior is possible, but has some drawbacks. Running an extension cord into the car is one: I'd recommend to install a socket on the car (maybe recessed into a bumper) instead of running a cable through a door gap. With a permanent installation, it's much easier to run the cable from outside to inside in a safe way.

Then there's safety: you need a space heater that won't overheat when it falls over.

Answer 2

You could have a block heater installed. A block heater is a heating element that runs on household current. It is usually installed either in place of a freeze plug or in line of a large radiator hose. The power cord will then be run through the grill for access. The heater warms the coolant in the engine block and radiator. You could theoretically switch the power source via a timer. This would require some experiments to determine how much time it would take get the coolant to sufficient temperature at various ambient temperatures.

Answer 3

You're overthinking this. Just:

• start the car
• turn the heater on
• lock the car with the keyfob (engine and heater still running)
• go back inside your home and have a coffee for 20 minutes

Answer 4

A tube heater (first hit on google) on the dashboard does a good job. You can either run a suitable extension through the door seal (I suggest the bottom in case of rain/snow/meltwater, and the driver's door so you don't forget about it). The tube shouldn't really touch the plastic of the dash, but in my Transit the end caps are the only points of contact and they stay cool. In the car I have to position it carefully so the tube doesn't sit on the plastic. Using the supplied brackets perhaps with an extra baseplate would help too. Remember to stow the extension lead away safely when you drive off.

I tried this recently at around -5 C with a 40W heater (I'd forgotten the windscreen cover the day before). In about 20 minutes the patch directly over the heater was completely melted; the rest of the ice had detached from the windscreen and brushed off.

This will also take the chill off the cabin and prevent the windscreen fogging up before the engine warms up.