Best Ethical and Sustainable Thermals In The UK To Keep Cosy

Looking for the best ethical and sustainable thermals to keep you cosy? Here are my top picks – from vegan-friendly bamboo to cosy ethically sourced merino wool and more.

I used to think thermals were just for mountaineers and skiers. And then quite some years ago my parents retired. Suddenly, their wardrobes expanded with a full array of thermals for almost every occasion.

I thought they had taken up mountain climbing or some other kind of alpine pursuit. And then I realised, no. There were no alpine adventures. They were just looking for ways to keep the heating off for as long as possible, now that they were at home much more often.

My parents have always been the original energy savers. In fact, I feel like I’ve learned almost all that I know about saving energy from them. But I’ll be honest, I did giggle at them when they were decked out in all their thermals.

But life has now gone full circle, and in response to rising energy bills, I’ve found myself thinking that my parents have been on to something all these years.

As such, I’ve found myself searching for sustainable thermals as a way to keep warm when working from home, without resorting to cranking up the heating.

So whether you are concerned about heating costs, and are looking for a way to stay cosy at home without turning on your heating so much. Or whether you are looking to get out on some alpine adventures without freezing your bits off, then here are the best ethical thermals I’ve found.

Ethical and Sustainable Thermals Guide

No matter if you are vegan or you prefer natural fibres, I’ve sourced the most sustainable and ethical thermals. From performance wear to casual wear, there’s something for every circumstance.

To help you out, I’ve included a rough price range for each brand. The key to this guide is:

 £ = Under £50 | ££ = £50 – 100 | £££ = £100+

Joha: Best For Natural Fibre Thermals

Budget: £

Caters for sizes XS – XXL

For cosy ethical thermal baselayers, then try Joha, a Scandinavian brand that’s been going for over 50 years.

When it comes to thermals, this brand knows its stuff – it only makes thermals, and makes them well. All of its products – from long johns to vests, boxers, and long-sleeve tops, are made from mulesing-free merino wool and/or organic cotton. There are no synthetic fibres here.

What’s more, all of its products have Oeko-Tex Standard 100 certification. This means that every component – right down to the thread – has been tested for harmful substances. For extra peace of mind, Joha also holds Scandinavian independent certification for the responsible sourcing of wool.

Shop women’s Joha thermals and men’s Joha thermals in the UK via Alpinetrek.

BAM: Best For Vegan Bamboo Thermals

Budget: £ – ££

Caters for sizes: men’s S – XXL / women’s 8 – 16

For vegan-friendly base layers, hot-foot it to BAM. With bamboo baselayers for both men and women – these soft and stretchy insulating base layers help to keep you warm on even the coldest days.

Designed for both performance and comfort, the flatlock stitching means these sustainable thermals are chafe-free.

Made from bamboo jersey blended with organic cotton, this sweat-wicking blend is designed to be just thick enough to keep you warm, yet highly breathable so you don’t overheat. The blend is also incredibly absorbent so it helps you to stay dry, helping you with your temperature control.

From long-sleeve to short-sleeve tops, and zip-neck tops to help keep your neck cosy, to long johns for men, BAM has a great selection.

What’s more, BAM only works with responsible producers. For example, BAM only works with bamboo fibre producers who use safe and responsible chemistry and waste treatment practices. These producers are committed to investing in the technology needed to further improve their practices, processes, and chemistry where necessary.

BAM also ensure that its suppliers are paying their staff above the national minimum wage and are offering good working conditions throughout the entire supply chain.

I wrote more about BAM and its ethical commitments – if you are interested in reading more.

Shop women’s base layers and men’s base layers at BAM.

Polarn O. Pyret: Best For Kids Thermals

If you have kids and are off on outdoor adventures together, then Polarn O. Pyret is a solid choice when it comes to kids’ ethical thermals.

Offering thermals made from responsibly sourced wool, and recycled materials, for babies up to kids aged 12 years, it’s a great place to pick up thermals that will last and last. In fact, Polarn O. Pyret says that every garment is made to last at least 3 children, if not many more.

Polarn O. Pyret also runs a buy-back scheme. Here, when your child grows out of their Polarn O. Pyret clothes, it will help you find a new owner for them. In return, you’ll receive a voucher to use on new items online.

As always, as I come across more ethical thermals, I’ll be sure to add them here, so do check back again.

Looking for more ways to keep cosy? I have you covered. Try my guides to ethical jumpers, ethical hats, ethical gloves, and ethical socks.