Why does one of my lightweight rugs make my horse sweat?

[Charla]

I have a warmblood who is currently in a no fill turnout at night and naked in the day if dry. I have 2 no fills, both different makes, one a combo and one standard. When I put the standard neck on him he doesn't seem very warm at all, day or night. Yet when I put the combo on him, if I don't take it off before the sun is out, he starts sweating in it. I've never had this with him before! Why does that particular rug make him sweat and the other doesn't even keep him warm enough when they are both no fill?!

 

[be positive]

The no fill rugs vary in quality, most are not suitable for use in colder wet weather as they lay the coat flat and so causing horse to actually be colder when wearing one than turned out with no rug.The one with a neck is probably more nylon, I think of some as almost being like a plastic material, these can cause sweating but the horse can feel chilly and clammy.
I will not use them once it is cold and wet although I have an Amigo that is not too bad. I would try yours in a light rug with 100gm fill or leave him without one.

 

[StormyMoments]

most heat escapes from their neck so if hes hot and his neck is covered too he may very well sweat also is it old? some older rugs arnt breathable

 

[Slinkyunicorn]

He is probably too hot in it! My WB never wears combos - even in the snow last year - even when fully clipped as he gets too hot. Just leave him with the no neck one - if a horse feels 'toasty warm' under any rug it means its too hot! It is easier for a horse to warm up than cool down - they are designed differently from us and do not feel the cold in the same way.