Do the teardrop shape helmets save that much time over 56 miles?
Oh my - you must be new around here 
Welcome!
Short answer is yes - and quite a bit.
Next answer is no - they are not hot, even in 90 degree F days.
Last answer is none are faster than an another since it depends on the individual rider, how it sits, etc.
Most would argue the Louis Garneau Rocket the best regarding tests, fit, price, etc. for the average rider.
Thanks, Yes First time on the forum. My third year in tri’s. and my first half ironman will be in june.
Yes I am looking at the rocket. Thanks for your help
Are you only worried about the physical advantage or do you also want to know about the psychological advantage?
A couple years ago (November 2005) I helped out at the Dragon Sports tent at IM Florida. This was the first time where I sensed a panic amongst many regular helmet wearing triathletes watching squadrons of aero helmet clad triathletes ride by the days before the race. 
Herbert
… I sensed a panic amongst many regular helmet wearing triathletes watching squadrons of aero helmet clad triathletes ride by the days before the race.
Oh, now there’s a quote right there Herbert!
You will learn that the game is in getting fit and shaving seconds (or minutes) based on one’s budget. Having said that, aero helmets give the most timesaving punch for the ‘least’ amount of money that an OCD tri-freak (like most of us are) can get.
Aero wheels look cool, and I’ll be using a rented version for those, but I was sure to let Santa know that I would be happy to risk the silly look of an aero helmet (Giro Advantage 2 for me) for the benefits.
Just remember: the benefits are really only good on the bike portion, won’t help much during the swim and run. But, if you want to try that out, please post the pics
Thanks, I think aero will be the way i will race from now on.
I just upgraded to a new aero helmet as a Christmas gift to myself. This beautiful Giro Advantage 2 will replace the LG Crono that has served me well.
Just picked up the Rudy Project one today.
LOL, mine just arrived at the front door a few minutes ago. Sweet!
And guess what helmet Chrissie Wellington used to win IM Hawaii … ?
IMHO, they look cool, and thats about it. Since I’m not racing to win, I wear one just for the psych effect. Also, don’t feel like you need to pay upwards of $140 for a helmet. I thought this was a litte ridiculous, so I managed to get an LG rocket from ebay for less than half that.
There is an old issue of Triathlete magazine a few years back (I want to say the one with Desiree Ficker on the cover) that showed a picture in one of the articles of a guy wearing a helmet with the same paint job as your Chrono. Was that you?
And guess what helmet Chrissie Wellington used to win IM Hawaii … ?
as been discussed many times before Aero helmets provide no advantage in hawaii if you pass out from the heat halfway through the bike portion. Just because she didn’t wear one doesn’t mean it isn’t faster aerodynamically.
Grant
It was indeed, a great shot by John Segasta.
He shot this pic way low from the back of a moto and made me look fast.
How funny. I was just rereading that issue when I found it at the bottom of my desk at work today and thinking what a cool paint job that was.