180w may do well in your California climate, I don't know.
On the wet coast my truck fogs as soon as I get on the highway in the rain. I went with out a heater core for a week and bout a 300w plug in the c-lighter heater for $30. I knew what I was buying having used one years ago in our Bug, all it will do is move warm air (if you can call it that) to the glass it's pointed at meaning if you point it at the drivers side thats all that will stay defoged. Mind you I only bout it for frosty mornings and it kept my side clear. If your serious about extra heat I'd sugest at least a 1000w heater but I don't know if there is a dash top model avalibe.
For fog I like RainX defoger that you should be able to get at any auto parts store, a little does alot. The only thing I don't like about RainX is if it rains everyday, I have to wipe the windows every morning and then after work. I tried a 50/50 mix with methol hydrate and it stayed defoged for a few days but the cab smelt like sour moonshine. Optical shops sell defoger and it's darn good stuff that lasts days but it is pricy for what you get.
