I think you might find the reason the smaller bore hose isn't used as much on big reels (50m or more) is that most of us have 60 psi pumps.
When you get up to 50m of the air hose the flow rate is almost non existant for cleaning windows.
You need the 100psi pumps.
From what I now gather, these pumps cope with the smaller bore hose very effectively.
I too have the same type of system as ro man supplies, it works fine, and if someone is trying to say that water gets thicker as it gets colder...er, well, they are the thick ones, very unusual stuff is water, and it has many properties that make it an incredible substance, getting thicker in the cold isn't one of them!
When it gets thicker you will know about it...its called ice
The cold does affect R/O membranes though, their efficiency drops a little apparently.
The expensive R/O setups are top stuff, and if you are a two man operation then you may well need one that will produce more pure water in a given time.
If your work is all domestic (or mostly) and a large percentage of that work is on housing estates, for a rough guide, if you allow 18l of water per house that should give you an idea of your water needs.
If you are cleaning....say 20 houses a day (or the equivalent) then you could need as much as 370l of pure water a day.
Even on a really heavy usage day I haven't got near that yet, so that would be enough for the average days work I would have thought.
And that is doing all of the windows, and not just the upstairs with the WFP.
18l of water per house is a very generous allowance too.
The small systems will cope fine with producing this much water, if funds are an issue, the cost of buying the smaller unit might make sense, and you can always upgrade to a bigger system in a couple of years time when your work has increased to the point where you actually need to go bigger.
It isn't just the cost of the R/O system you have to consider, the pre filters and DI tank you will need are also larger and far more expensive too.
You can end out spending an awful lot of money you don't need to, at least in the start up phase.
Regards,
Ian