He did a lot of hiking but didn't like the gear he used, and thought of creating his own yak product.
"It feels amazing, I'm sure it must be amazing if they can live in these sort of conditions in the winter, I just thought I can combine this fibre that I've found with something that I'm really passionate about."
The yak wool is sourced from yak herding communities on the Tibetan Plateau.
Warnaar is one of the first to be in the clothing niche, after crowd-funding over $50,000 to manufacture the garments.
He said he wants to change the way outdoor clothing is made.
Compared to other fibres, yak wool is more sustainable because yaks aren't farmed specifically for wool.
The wool is a bi product, so regardless of demand it would be growing in the Tibetan Plateau. Yaks aren't shorn, but rather combed before the wool begins to fall off in Spring.
"I think more and more people want to buy outdoor clothing that promotes and sort of preserves the whole natural outdoor environment and the people living there," said Warnaar.
His business has the mantra that every step should be beneficial for every person involved in the process.