It gets a bit chilly here in Kent over the winters, but my old unit was hardly blowing any air so it basically did nothing anyway! (i always had a sponge and a scraper handy to get rid of condensation AND ICE on the inside of the windscreen).
The unit will be running the demister and the footwell, i'll still have fresh air from the dash vents, just not currently to this heater but there may be scope for change depending on how it works over winter. If in doubt, i'll just crack the window open a little
So this is a decent comparison of the size of the units. MUCH smaller.
Here is the front switch panel. Its easier to work with it out to give your hands a bit of room. You can see that i've moved the temperature pull to the left where the choke would be on older cars and the actual unit it connects to is now behind the glove box. On the right is where the potentiometer sits (it has a separate control unit that i need to find a home for. As you can see, my wiring is a bit of a mess at the moment, i was working out where was best to run everything.
Last one in situ (sort of). Pipes are just loosely fitted with the 5/8" to 1/2" reducers, not fitted the pipes to the demisters yet as they were getting in the way, but you can see the holes where they attach. I may keep the unit slightly angled like this (but not as much) as it gives a bit of extra clearance to the pipes at the back and still keeps it fairly hidden from view at the front
Its a slow process for me between work and having a garage full of junk that i can't use at the moment. So its just when i can get time.
Certainly be worth it in the end!