Reviewed: Is Uniqlo’s HEATTECH better than traditional winter clothes? A Singaporean uses two buns to find out.

Uniqlo HEATTECH has already started to replace Singaporean’s go-to thermal underclothing, but how effective is it, really? It’s silky, thin, almost to the point of flimsy – and yet we go on buying it. How does it compare with long johns, flannels or traditional winter wear? To what extent, exactly?

To get to the bottom of this – we enlisted the help of a couple of dabaos, a temperature probe, an extra toasty HEATTECH undershirt, and a flannel shirt off a friend’s back.

Flannel shirt, HEATTECH top, and two of Nam Kee Pau’s Big Pau in what appears to be the weirdest flat lay ever.


Our idea is to cover the heated buns with HEATTECH and/or regular winter clothes for a period of time before measuring to find out the drop in temperature difference. Et voila, we find out which material keeps you warmer!


This writer had the idea that Dabaos are like humans. Well, in the sense that they are meaty on the inside and covered with a layer of skin on the outside – oh, and they’re delicious too! *creepy smile*


Seeing that we’re in Singapore and we can’t exactly recreate cold conditions without travel – ahem, ahem, CORVID-19 travel restrictions. Aside from that, it wouldn’t be accurate to test these on people since everyone has a different resting temperature and responds differently to heat/cold.


For our results to be accurate, we let our Dabao buns to rest until room temperature before microwaving them together, so that they both rested at a toasty, feverish, human-like temperature of 38 degrees. We stabbed them both with a temperature probe to check that the temperatures were as close as possible.

Warm and toasty — but not as cute as the baby Bao in the Pixar film.
Easier for us to “stab” them for temperature taking.

We then covered each bun in clingwrap (for hygiene purposes) and then laid a thick flannel shirt on “Bao A”, and a Uniqlo HEATTECH sweater on “Bao B” for an hour.

From left to right: Bao A was covered in flannel and Bao B was covered with HEATTECH.
 Temperature After Microwaving (Celsius)Temperature After Covering For 60 Minutes (Celsius)

We were surprised to find that both the flannel and HEATTECH buns lost very little heat! We decided to monitor the temperature for another 30 minutes.

A big-ass bun being probed with a long stick? Make of that what you will.

After taking the temperature again at 90 minutes, you can see that both baos lost almost the same amount of heat with almost indiscernible ~0.1 degree Celsius difference at the end point of our experiment.

 Temperature After Microwaving (Celsius)Temperature After Covering For 60 Minutes (Celsius)Temperature After Covering For 90 Minutes (Celsius)
FLANNEL BAO A38.437.834.4
HEATTECH BAO B38.637.234.5

Overall, this is rather impressive considering how much bulkier the flannel is compared to our pink HEATTECH top. It may also be noted that the flannel seemed to display more consistent heat loss. Our HEATTECH initially showed faster heat loss but held on to more heat towards the end.

Although we were hoping to see a more drastic end to this experiment, I’m afraid these critics will have to concede… yes, the HEATTECH is actually effective and on par with traditional cold weather garments.

For this strange and crazy experimental stunt on Uniqlo’s HEATTECH, it really and truly deserves its final BRUTALLY APPROVED rating.

Want to see more of us pitting two things against each other? We compared two authentic Korean restaurants in this article!

Love reading about fashion and clothing? Get the lowdown and read our review on Wehr Singapore Men’s briefs. 


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