I generally have RO water in my car, and use the cleanest water available wherever I am, but can’t carry a bottle at all times.
How do you warm it?
In my experience using saline nasal flushes, having the water at room temperature hasn't really bothered me, as long as I've added the salt.
Someone else responded to my question saying the same thing. I tried using distilled water at room temperature (with the salt) and it REALLY hurt my nose. Feels great when the water is luke-warm. Maybe I am the only one.
I'm sure you're not. For me it's uncomfortable but bearable at room temperature. Much more comfortable after 12s or so in the microwave.
Could try microwaving it or using a chemical reaction to heat it, like an MRE meal.
I would recommend placing the bottle in a hot/warm water bath. Like how baby bottles are warmed.
If microwaving, make sure to mix well!
The temperature doesn’t make any difference to me.