There’s a popular saying when it comes to the elements, “theres no such thing as bad weather, only bad clothing”. And whilst I maybe slightly disagree with it, it does have a point. The right clothing can massively change your outlook on the weather, and make sure you still get to enjoy the day. I caught up with Mac in a Sac at the National Outdoor Expo 2025, and they offered to send me a few of their latest products to review, including their Synergy Insulated Jacket as well as their Travelite Backpack.
As always with gifted reviews, Mac in a Sac have had no input in this article besides gifting the jacket.
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- Mac in a Sac Synergy: Our Verdict
- Mac in a Sac Synergy: Technical Details
- First Impressions of the Mac in a Sac Synergy
- Where to buy a Mac in a Sac Synergy Jacket
- Style and where to wear
- Colour Options
- Materials
- Comfort
- Fill power
- Want to see more travel and outdoor gear?
- Packability
- Stuff Sack
- Waterproofing
- Out in the Elements
- Mac in a Sac Synergy Jacket: Final Thoughts
Mac in a Sac Synergy: Our Verdict
Pros
Cons
Mac in a Sac Synergy: Technical Details
| Feature | Details |
|---|---|
| Dimensions | 16cm x 22cm x 47cm |
| Weight | 377g |
| Sizes available | XS to 3XL |
| Water repellence | 600mm |
| Colour Options | Jet Black, Burnt Orange, Khaki and Sapphire Blue |
| Filling | Thermolite fill, 550 fill power |
First Impressions of the Mac in a Sac Synergy
So my last product from Mac in a Sac was the Origin Waterproof Jacket. I bought this myself a few years before, and I have carried it with me ever since. So I was excited to see what was next. I immediately tried the Synergy Jacket on and it feels really comfortable. The materials feel like they are good quality and it looks good on me too (I think so anyway).
I will say that it took me longer than I expected to test this. The jacket arrived in April, and the UK has had a year where it’s been incredibly hot. So there hasn’t been a huge opportunity to test it. Which is why this is only being published much later into the year.
Where to buy a Mac in a Sac Synergy Jacket
If you would to purchase my favourite jacket for travel. Check it out using the link below to Amazon.
Style and where to wear
Whether something is stylish or not will always be a personal preference. For me, this style of jacket is something I wear often. I love how I can throw it in my bag on a day hike, but I can also bring it into the city and it fits in just as well. You see people wear these style puffer jackets all the time in the city. The difference between theirs and mine, is that when I get hot I can stuff mine into my bag and cool down.
But its primary place is in the great outdoors, and it works beautifully. Any hiker will tell you the key to being comfortable is layering. You want light layers you can whip off and on to adjust to the temperature. Its weight means it doesn’t add a lot to your pack, so there’s no reason not to bring it.
Colour Options
I love the colour options, with black, blue, khaki or orange for men. Women have a choice of ivory, teal, navy and watermelon. So you can choose a colour based on where you will use it most. If you are hiking or often out in the wilderness, then for visibility and safety I would go with orange.
Since I mostly use these on walks around the city or well trafficked areas, I went with the sleek black. I wanted something for when I was doing street photography and as much as I love Khaki I already had a similar style jacket, and my Rab Jacket is already navy blue.
Materials
The insulation is made from Thermolite, which is a synthetic alternative to down. So you can wear this without any worry about ethical implications. The build is also PFC and PFOA free, reducing any harm to the environment during production.
I sometimes worry when I see a product advertise heavily how its materials are sustainable. I get concerned this has come at a compromise to quality of the products longevity. But that isn’t the case with this jacket. Every stitch feels like its been done with care, and I am confident this jacket will take care of you, provided you take care of it. The zips are even YKK which are renowned for their consistency and quality.
Comfort
Wearing this jacket is really comfortable. I love down jackets as they often flex and feel really soft. The cuffs are elasticated, which is perfect for keeping out a chill. I do have a habit of rolling my sleeves unless it’s really cold, so this does make it a little harder for my habit. Fit wise I am usually a medium and this fits true to form. The jacket isn’t too large or small. It does feel close to my body as a good insulation layer should. I will point out there is no elastic at the bottom so you can’t cinch it in the create a warm seal in really cold weather.
The Thermolite filling as well as providing insulation makes the jacket soft to wear. They make the baffles thick and puffy, which makes the jacket feel comforting. It’s quite impressive how something that is this puffy packs down so small.
Fill power
The Synergy is a thermolite filled jacket, with 550 fill power. This makes the jacket more suited for everyday conditions rather than anything extreme. Spring or Autumn evenings would be perfect, or when on a brisk hike. This is a great all year round jacket, as sometimes even in the summer there can be a chill. I would not recommend it for expeditions to Iceland or the middle of winter. However you can push it a little further if you choose to layer properly.
Want to see more travel and outdoor gear?
Packability
Having a 550 fill power gives the Synergy Jacket a good ratio of warmth to compressibility. For me, that is ideal in the UK, especially at the end of the seasons. The amount of days we have that start off chilly, turn into a scorcher by the afternoon, and at the end of the day you’re in a beer garden colder than the lager in your hand.
It also keeps it nice and lightweight, so you don’t mind throwing it in your bag for emergencies. I hate when I take a coat and it gets too hot so I am forced to carry it. The thermolite filling keeps this jacket packable and lightweight. If you do want an even more packable version, they do a gilet. Although the difference in bag sizes I would imagine is minimal.
Stuff Sack
Like their waterproof jackets, the Synergy jacket comes with the addition of a stuff sack for easier storage. This is great as it makes it much easier to pack into a bag. When I have a coat loose in my bag it always gets in the way when I need to find something. The stuff sack keeps it packed away and organised, making it much easier to see the rest of the contents of your bag when you aren’t wearing it.
It does feel a tad bulky in the stuff sack, it isn’t as small as the Mac in a Sac Origin but that is mainly due to the baffles. Still the good thing is you can squeeze and force it into the smallest of places without any worry about damage. It definitely packs down smaller than a lot of other down jackets on the market, but when packing your daypack be a little bit generous with your allowed space.
Waterproofing
In the elements, cold and wet go together hand in hand, so it’s great that this jacket has some waterproofing. The jacket is rated to 600mm, so light or weak drizzles. It’ll be fine if you get caught in it, but if it was raining I wouldn’t rely solely on this. Luckily you can always layer it with the original Mac in a Sac, the Origin jacket for heavier rain.
Out in the Elements
Of course the main object of this jacket is how it performs when being used. It doesn’t matter how good it looks if it fails to keep you warm and dry. But I have loved this jacket so far. As we get more into the winter months I’ll update this post, but so far its been perfect for chilly evenings. I have taken it on nights out where I knew I would get a chill. I live fairly near the sea and the chill can be biting even in summer evenings when you are walking along the seafront after dinner. So I’m really glad I have brought this along with me.
Mac in a Sac Synergy Jacket: Final Thoughts
I loved the versatility of the Mac in a Sac Synergy Jacket. It’s practical and versatile. I can wear this in the City of London but equally it’s just as suitable if I fancy a day hike. Good travel gear should be lightweight and packable, but without compromising performance. And you get that with the Mac in a Sac Synergy. I will no doubt be getting a lot of usage out of this waterproof packable jacket in the future on my trips. It is perfect for if you fly to a hot country, but don’t want to bring anything too big to keep you warm on the flight.