Having done a spot of window cleaning in the past I find that a tiny squirt of washing up liquid and a splash of vinegar in warm water works really well.
An applicator and squeegee make life a lot easier.
I bought one of those karcher window vacs and they are the bees knees. I have got two big dogs and my inside windows( Ive got 5 french doors as well, 2 doubles and a single) get a good coating of dog paw mud and dog nose wipe. I wash the glass with a wet (not sopping dripping) cloth using a bucket of dilute hg window cleaner till the yuck is off, then dry the window. The result is amazing, very easy, very quick, and smear free.
You don't need hot or warm water, cold works fine - you just need a good detergent. I use fairy washing up liquid, make the water about the same strength that you'd use for doing the dishes.
A bit of practice using a squeegee and you're away - smear free every time. You could always get a window cleaner to clean them for you and if you ask nicely, they might do inside as well - a bribe in the form of a brew helps ....... I'm a window cleaner by the way :)
E-cloths. Magic. One to use wet to wipe over in pure water (no detergent or anything) and the other to dry off. No smears, no chemicals, no elbow grease needed. A revolution.
I have one of those Karcher window vacs and I love it. You do have to charge it up on a regular basis, but it's a small price to pay for the convenience, IMO.