short commute (3 mi) + winter = defrost problems

[Daox]

My wife is now driving the Paseo to work and back. The one way trip is right around 3 miles. Definitely not enough time to get the car up to temperature. The heat isn't a problem since the trip doesn't take but 5 minutes. The problem is defrosting. Now, I have a block heater that I plan on installing real soon. Its a beefy 1000W circulating unit. However, I'm also thinking about adding a cabin heater like this. I can put the whole thing on a wireless remote and flick it on 1hr before she leaves each morning.

My question to you guys is has anyone used cabin heaters and how well do they work for helping with defrosting issues? Do you think that the block heater will be enough for defrosting?

[Ryland]

I have the same issue, right now it's warm enough that it's just fog and not frost, but to defog I've been using my little 22 watt solid state dehumidifier, of course once it gets cold enough that starts to frost up and stops working as well, but when it is warmer it works quite well at keeping the inside of the car dry and fog free.
I also plan to try using a ceramic 12v heater that plugs in, kind of wimpy but it should help.
I think the, that the Dash Sock (full of silica gel) or the dehumidifiers of the same idea that you plug in to cook the water out, should work no matter how cold it is.

[JRMichler]

I also have a 3 mile one way commute. It's normal to get to work with engine temperature below 120 deg F on a cold day.

I just leave the heater blower on low all winter, the air selector on Defrost, and the heat on full hot. My truck is parked inside, so is slightly warmer than the outside air when I start out. The combination is enough to keep frost from forming on the inside.

If you park outside, then you have a challenge. Radiation to the night sky makes the car colder than outside air temperature. I'd try some sort of car cover first. It that's not enough, add some heat to the cabin. I'd try a 100 watt light bulb for an hour or two ahead of time and adjust depending on how well it works.

[ConnClark]

two words for you "block heater"

[Daox]

Originally Posted by Daox

Now, I have a block heater that I plan on installing real soon. Its a beefy 1000W circulating unit...

I believe I mentioned that. Just not sure if that is enough.

[Ryland]

This is the brand of car dehumidifier that I have and as you can see they also sell for about $20 a silica gel dehumidifier and to me, if the inside of your car is dry then it doesn't matter if you have heat coming out because there shouldn't be enough moisture in the air to fog up the windows.
Calculations to figure out of course would be to see if a 1000w block heater does more good then a 1000w space heater (Ben was using an oil filled space heater in his electric metro), of course the block heater is going to allow you to get better mileage and with luck have heat right away, where the space heater is just going to help with heat and maybe defrosting windows.
From my figures last winter, plugging in a block heater used less energy then running a cold engine, so I think you should install that block heater while the weather is nice! I would do the same thing in my civic but I broke the last to sockets I had when trying to remove the plug where the heater screws in to.

[ConnClark]

My experience with a block heater is it makes a big difference even when used for just 10 minutes. No you won't get instant heat with it but your engine will warm up to operating temp much quicker. Another thing you can do is start the car with it plugged in while you scrape the frost from your windows. Any way you look at it you come out ahead, electricity is cheaper, you save your engine from some wear, and you save fuel.

[JRMichler]

If you are parked outside, the car is colder than the air because of radiation to the night sky. It will stay frosted until the windshield is warmer than the air. This will take some time, even with a block heater. That 200 watt cabin heater should do the job. It will work even better if you cover the car with a tarp.

[Frank Lee]

Originally Posted by Daox

I believe I mentioned that. Just not sure if that is enough.

A cheesehead not familiar with block heaters?

It should certainly be enough. In fact when I use a block heater it defrosts the little areas right above the vents before I even start the engine, simply because the heated coolant is thermosiphoning through the heater core and I've left the controls on "hot".

First thing: grille block.
Second thing: engine blanket.
Third thing: block heater- and it doesn't need to be on more than an hour either. Depending on how cold out it is, you can probably get away with less, maybe down to 1/2 hour?

[oil pan 4]

I had a 2 mile drive into work for the last 5 years.
What I would do is put a 110 volt space heater in the seat of the vehicle where it couldn't tip over and run the extention cord from it into the house, leaving it unplugged. Then all I would have to do is plug it in 10 to 20 minutes before I leave and the car would be nice and warm and all de-iced.
If the car is coved with iced on snow you might need up to an hour. After that time the door seal will be un frozen and the snow should be ready to fall off the cab of the vehicle with nothing more than the touch of a brush.

Something to look out for:
When it was got real cold the 2 mile drive would kill the batteries in my truck over the course of a week. The charging system worked fine, the glow plugs and cranking took more power out of the batteries than the alternator could put back into them in the short 7 to 8 minute drive.

Thinking ahead, when I built my new diesel engine I put 2 block heaters in it, 1 block heater was good, 2 should be twice as nice and installed a 1.5amp battery charger too. The combonation works very well for cold starts, leave the 1.5 amp charger on all night and plug in the 2 block heaters at least 15 minutes before I leave.
The next gasoline engine I build will have one block heater in it for sure.