Since you don't want to heat the room with the towel warmer, I'd be more concerned about the average temperature that the unit gets, whether it has a programmable timer and maybe even a temperature control so that you have the towel toasty warm when and how hot you want.

I don't know about curved bars; you bring up a good point. I do know that the more layers you can create on the warmer, the more insulation you provide for the towel to stay warm. So, you're right about the number of bars so more surface area touches the towel as well as making the towel thick as you put it on the bar. Hope that makes sense.

Here's a towel warmer that looks like it meets most of your needs.

Good luck with your project!

Here is a link that might be useful: Towel Warmer that meets your needs

Thanks, MMhappy. I was definitely planning on a timer - I've learned that lesson from the plug in models I've been using for the last few years.

After I posted the question, I spoke with my brother who just remodeled his bathroom and he recommended this one which I had already been considering so I think its the one I'm going to go with.

Here is a link that might be useful: Myson towel warmer

Looks like a nice one! Good luck with your project! :)