Wetsuit vs. Non-Wetsuit Swim Test

I had a swim workout planned for today, so I thought I'd do a little test and see what the time difference would be swimming without a wetsuit. Headed off to Walden pond where the distance across and back is pretty darn close to a Half Ironman (1.2 miles...2112 yards). I base that on my average swim time there vs. my average half IM time, and they are within a minute of each other. Normally I swim with an Ironman Stealth sleeveless wetsuit. I didn't wear my HRM today, but since my swim times are usually pretty repeatable (within a minute or so), I went strictly by stroke turnover and rate of perceived effort (RPE).

Normal Wetsuit Time: 37:00 / 38:00 minutes
Non-Wetsuit Time: 43:00 minutes

I was pretty surprised, but then I half expected the results. It was definitely harder, I couldn't relax as much and I was more tired than normal at the end. I'm a middle of the pack swimmer, base on my 19th place out of 43 in my age group at IMLP. Losing 5-6 minutes for a 1/2 IM is pretty significant. I figure that it would have cost me even more over the full IM distance, because I definitely would have been more tired. I might have been looking at a 13:00 / 15:00 minute loss for the 2.4 mile distance.

I guess the bottom line is, for me anyway, that anything over the Sprint distance is worth using a wetsuit, since the time lost in transition would be more than offset in the water. And I'd feel less tired getting on the bike. For the Sprint distance, maybe I'd lose a minute or so? Kind of a toss up as to whether it's worth it. Otherwise, it looks like the bottom line is "Get all the flotation you can afford!"