I know this topic has been written about to death, but I can't find an existing thread that answers all of my questions and needs or talk about exposure suits for temperature ranges that I dive in.
I currently dive in Sweden where water temperatures regularly get down to 0°C winter season but might touch 22°C during the summer, but I'm more concerned about diving in the colder temperatures. Atm. I use a rental neo drysuit but would like to get a trilam very soon. However, my undergarment system right now is mixed layers of different materials like wool and fleece. Now, I am looking to build a true dedicated drysuit undersuit/undergarment system but have some preferences. I dive recreational with a single tank so dive times aren't all that long. Even then, I tend to be cold and easily freeze in my hands and feet (I always have cold hands and feet, even out of the water).
I'm looking to build a system with maximum warmth in mind but also with minimal bulk, to minimise extra weight requirements but keep good mobility. That's why I am thinking about electronically heated options like undersuits, vests, shirts and such. The thought is to have a thinner undersuit that can be electrically warmed up to be similar to a thicker undersuit. They may also be used together with a base/mid layer garment as well if needed. I know of quite a few brands that sell heated garments: Santi, SmartTex, Venture Heat, Thermalution, Heizteufel, etc. I also know of some heated gloves and a couple of heated socks by the same brands and have even thought of heated insoles, all for added warmth to the digits. Any thoughts and/or suggestions on the heated garment route? Santi BZ400, Flex 2 undersuit and Flex 2 vest are often named. I personally like the idea of the full undersuits for the heated arms and legs. Anybody with experience with them? Could the Flex 2 when heated (preferable as it is thinner) be as warm as the BZ400 unheated or equivalent undersuit? For gloves and socks, I'm partial to thinner materials to keep dexterity in the dry gloves.
Apart from heated garments, I also find the FE Halo AR interesting. Using argon to make a warm yet thing undersuit makes it really appealing. Anybody know how well they work? I realise I would have to use layers with this undersuit and would likely use FE or Waterproof layers. Any other suggestions for maximum warmth with minimal bulk?