Trespass Unite360 Unisex Thermal Base Layer Set review
By Tom Calder
A thermal top-and-bottom set is one of the cheapest, most reliable ways to stay warm when the heating is off, since it needs no power, fuel or batteries. Generic synthetic sets do the job well for occasional use; just check sizing and don't expect the comfort or odour resistance of merino.
- Best for
- Cheaply adding real warmth during a winter power cut or in an unheated home
- Skip it if
- You already own decent thermals or merino kit, in which case a second budget set adds little
as of 2 Nov 2026, 16:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.We earn a commission if you buy through the retailer links on this page. It doesn't change our verdict. How we make money →
Researched, not used. We haven't used this product. This review is built from the maker's specifications, owner reports and our own sizing.
What we like
- Adds genuine warmth for very little money and packs down small in a grab bag or drawer
- Works with no power, fuel or batteries, so it keeps you warm when the heating cannot
- Layering traps body heat efficiently, which is cheaper than heating a whole room during a cold snap
Worth knowing
- Quality and sizing vary widely between generic brands; the cheapest sets can feel thin and pill quickly
- Synthetic fabric can feel clammy and hold odour if worn for days without washing
ⓘ As an Amazon Associate, PreparedBritain earns from qualifying purchases. We may earn a commission when you buy, or a fee when you request a quote, through our links. When two products are close, commission can decide which one we pick. A clearly better product always wins. Amazon prices come from Amazon's own product data and show the date and time they were retrieved. Prices at other retailers are checked by us, less often. Prices and stock can change at any time, so always check the retailer's price before you buy.
Our review
The Trespass Unite360 is a plain polyester thermal set, a half-zip top and leggings, sold as a unisex pair. It is the cheapest reliable way to add a warm layer when the heating is off, and it packs flat in a drawer or a grab bag. It will not match merino for comfort over several days, and the care label on the listing says hand wash.
What it is
Trespass describes the Unite360 as a 100% polyester base layer set: a long-sleeved top with a half zip at the neck and bottoms with an elasticated waist, which it says are made for insulation and warmth. Trespass's own page gives no fabric weight, no sizes and no care instructions. A Scout outfitter that stocks the set lists it as a 6 by 2 rib knit at 170 g per square metre in sizes XS to XXL, wicking and quick drying; the listing we link says hand wash only. Treat the fabric weight as a retailer's figure.
Polyester holds little moisture, so the set dries quickly and keeps some warmth when damp. It also holds odour after a day or two, which is the usual trade-off against merino.
Why a base layer is the first thing to buy
Ambulance and NHS cold-weather advice is to wear several layers of thinner clothing rather than one thick one, because the air trapped between layers does the insulating. A thermal set next to the skin is the bottom of that stack. It costs less than a day's heating, needs no power and works in bed as well as on the sofa. Our guide to keeping warm without heating sets out the rest of the stack, and our cold weather health alerts guide explains who is most at risk when the temperature drops.
One set per person is the sensible minimum. In a power cut that lasts more than a day you will want to sleep in it, and a second set lets one dry while the other is worn.
How it compares
On the keeping warm page the base layer set is the clothing item beside the wool blanket, the down throw and the hot water bottle. On our dedicated thermal base layers page the Odlo Active Warm set is the warmer synthetic for a higher price, and the Montane Primino and Mountain Warehouse merino tops resist odour for days of wear. Uniqlo's Heattech set is the mainstream alternative at a similar price. The Trespass set wins on cost and on being sold as a matched top and bottom in one order; it loses on fabric weight and on the hand-wash label.
Our verdict
Buy a set for each person who does not already own thermals, and try it on when it arrives, since generic sizing runs variable. Skip it if you already have decent base layers, or if it will be worn day after day with no chance to wash it, where merino is worth the extra. If the hand-wash label puts you off, a machine-washable Uniqlo or Odlo set is the alternative.
A researched review, built from the maker's specs, manual and UK listings; facts checked 2 Nov 2026. Sources: Trespass: Unite360 adults base layer set; The Scout Shop: Unite360 base layer specifications; West Midlands Ambulance Service: cold weather advice.
Who shouldn't buy this
You already own decent thermals or merino kit, in which case a second budget set adds little; and if you expect to wear it for days on end without washing, it is worth paying more for a merino set that resists odour and feels warmer for its weight.
Key specs
| Type | 100% polyester thermal top and leggings (unisex set) |
| Needs power | No |
This is a Researched review: we haven't used this product. We check every specification against at least two independent sources, re-check the UK price on a schedule where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
Best for Cheap, power-free warmth when the heating's off or the power's out.
in stock when checkedas of 2 Nov 2026, 16:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Best for Cutting heating bills by warming the person, not the whole room, during normal winter evenings.
as of 2 Nov 2026, 16:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
Best for Dependable home warmth during a winter power cut when the heating is off.
as of 2 Nov 2026, 16:07 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.Questions
What is the Trespass Unite360 made of?
100% polyester, according to Trespass, in a half-zip top and elasticated-waist bottoms. A retailer lists the knit as 170 g per square metre; Trespass does not publish a weight.
Can I machine wash it?
The listing we link says hand wash only, and Trespass's page gives no care instructions. A cool wash on a delicate cycle in a mesh bag is the usual compromise, at your own risk.
Is polyester or merino better for a power cut?
Polyester is cheaper, dries faster and copes with damp. Merino is warmer for its weight and resists odour over several days. For a kit that may be worn for a week, merino is worth the extra; for cost, polyester.
What sizes does it come in?
Retailers list XS to XXL. It is sold as unisex, so check the size chart against your chest and waist measurements rather than your usual label size.
Free alerts for your home
Home Alerts emails you when a power cut, a Met Office warning or a flood warning covers your postcode. Free for your own home. Sign up in a minute.
Start free →