I once did a sales course at F&P, and they told us that even the cold water detergents became significantly less effective below 20 degrees C.
Our front loader washes at 40deg.
Our previous LG top loader had a cold/warm cycle that was about 25 degrees.
Our previous to that F&P Intuitive Top Loader had Cold+ that added hot water so that the wash temp was 20degrees or above.
I find with the towels, chucking in the drier after they have dried on the line fluffs them up nicely. It is not detergent (at least not that I can smell), just a Front Loader thing (I have washed without powder and they still come out crunchy after line drying.