Warmup recommends towel warmers to be installed horizontal only. Towel warmer bars are designed to evenly distribute heat across the entire surface of the towel. Towel bars work most efficiently when towels are hung flat against them. Hanging a towel vertically reduces the surface area of the towel that’s in contact with the bar, which means it will take longer for the towel to warm up, and you might not get the desired warmth. When you hang a towel vertically, only a small portion of the towel comes into contact with the bar, resulting in uneven heating. In addition, towel bars are designed and tested to be installed horizontally, according to our installation manual. Installing them vertically could potentially compromise their structural integrity and safety.