DAM 35 Cooler Review and Testing

How long does it keep things cold?

Real-world testing

This a review and some tests of the DAM 35 Cooler, which uses vacuum insulated panels (VIP) instead of foam or other insulation, like from manufacturers like Yeti. I bought the DAM 35 cooler direct, using one of their 20% off promotions. MSRP is $219 but it's usually discounted. I got a blue one. It also comes in light grey, tan, and white. Yeti has a 35 that is $275. DAM was originally a Kickstarter project.

The DAM 35 cooler, per the manufacturer, has 0.85in thick VIPs. DAM claims an R-value of 50/in, but other resources point to different, generally lower numbers.For instance, one source indicates an R-value of 38 per inch for a VIP. That would put 0.85in as an R-value of 32, still substantial.

Polyurethane foam used by other manufacturers has an R-value of up to 6.5 per inch, so the "up to 3in" of foam that Yeti uses in their 35 cooler would thus be 19.5.

Regardless, the proof is in the pudding, as they say. The results of some testing are shown below.

TL;DR

The DAM 35, compared to the similarly sized Yeti 35, holds more, and the VIP insulation, despite being thin, is comparable to the Yeti 35. The DAM 35 price point is lower for similar performance, in a lighter weight.

Next, a quick review of the cooler itself, in comparison to the Yeti Tundra 35.

The Cooler

The DAM 35 cooler has slightly smaller exterior dimensions than the Yeti 35, but larger interior dimensions, i.e. it is bigger inside. Both coolers come standard with a small dry goods tray. The DAM 35 has options for dividers -- there are slots on the interior walls where panels can be placed to separate whatever is stored. The can be useful for separating drink types, for example. Water vs soda vs adult drinks.

	Length	Width	Height
DAM 35 Exterior Top	20 3/4	15	15 3/4
Interior Top	16 3/4	10 1/4	11 1/2
Interior Bottom	16	9 1/2
Volume: 31 quarts
Weight: 15 lbs
Yeti 35 Exterior Top	21 3/8	16 1/8	15 3/4
Interior Top	15	10 3/8	10 5/8
Interior Bottom	13 7/8	9 3/8
Volume: 26.5 quarts
Weight: 19 lbs

As for sitting or standing on the coolers, the DAM 35 supports 175 lbs. Yeti doesn't publish a specific figure for a weight limit; however, Yeti coolers are bear-proof, so I suppose that means a bear could put its weight on it and it wouldn't break, so it sounds like the weight limit is higher than 175 lbs. The DAM 35 is not bear proof. Both coolers are padlock-able.

Insulating with vacuum insulated panels is not new. Two other brands also have VIP coolers. One is Yeti, with their V-Series 50, at $800. The other is a German brand, unavailable in the US, called Qool, which has two sizes, a 28 for $375 and a 44 for $450. Qool ran a test of their coolers vs competitors and held ice for much longer -- it looks like their panels are quite thick.

Handles

The DAM 35 has rope handles with plastic molded grips that are free to slide. When not utilized, the handles just hang down. The Yeti 35 has similar handles,  but they tuck into the body of the cooler when unused. The DAM 35's handles hang from a tab that extends from the body of the cooler.

Closure

The DAM 35's closure mechanism comprises two rubber pulls with balls that fit into receivers. The Yeti has a similar setup. The difference is that the DAM 35 pulls are mounted below the lid and pull the lid down, whereas the Yeti mounts the pulls on the lid, with the receivers on the main body. It's debatable which is better. The DAM35's solution means that the pulls extend above the lid, which, while potentially being in the way, also facilitate getting your fingers into them to pull them loose.

Feet

The DAM 35's feet are grippy non-slip rubber. They're screwed in. They are removable, but at present, there are not alternate feet like Yeti provides (their sliding feet). 

Drain

The DAM 35's drain works very well. There is a screw in plug that will drain without fully unscrewing, though it will drain faster with full removal. Inside, the drain hole itself is below the floor of the cooler, enabling full drainage of any liquids.

Misc

Generally speaking, the Yeti is much cleaner, in terms of not having anything protrude from the main body. The hinges, handle mounts, padlock mount, and closure are all indented into, or are part of the main body. Conversely, all of the above protrude for the DAM 35. This is likely a function of how much thinner the DAM 35 walls are. The indentations made into the Yeti main body are quite likely to be indentations into the insulation, hence their marketing about "up to 3 in" of insulation, i.e. where there are indentations into the body, there is less than 3" of insulation.

The DAM 35 is not a rotomolded cooler. One of the stated advantages of rotomolding is to create even thickness walls, so that injected insulation can be optimally thick. With the DAM 35's VIP, that need isn't quite so important, as the VIP are independent of the plastic. It's unclear without destructive testing, how the DAM coolers mount the VIPs, but the top plate of the cooler is screwed on, so I guess that the VIPs are inserted into slots in the walls of the main body, then the cover plate is screwed on. The seam is not caulked or otherwise sealed, though I would guess there must be some sealing tabs internally. Will have to see how this aspect holds up in terms of durability.

Testing

There are various claims about how long coolers can keep ice. One can do controlled testing to compare different coolers. The testing reported here does not do any of that. This is uncontrolled testing. 

Test 1

This test put10 lbs of store-bought ice into a room-temperature DAM 35 cooler (approx 70°F). The thermometer was placed in the dry-goods tray, which was placed on top of the ice. It stabilized around 42°F for some time, and then you can see that the temperature suddenly went down to around 35°F. This happened because the storage tray fell off the melting ice block and started floating on the melt water. Then over the next period of time, the rest of the ice melted and the temperatures rose. Testing was stopped when the temperature rose above 50°F. The cooler was opened twice during the period for a quick look. This test was conducted inside, with ambient temperatures between roughly 68°F to 75°F, using a Thermopro TP357 Bluetooth thermometer.

The FDA safe food storage temperature is below 40°F, and the thermometer didn't get that low until later in the test. I think that the amount of ice was insufficient to be able to cool all the air in the cooler, and because the thermometer was in the upper part of the cooler, it registered a higher temperature. Lower down would have been below 40°F.

Time below 42°F: 3.5 days

Time below 50°F: almost 4 days

The Outdoor Gear Lab did a big comparison test of coolers, and their setup was 1/3 fill of ice, plus some chilled and unchilled cans on top. The Yeti 35 had 3.8 days below 40°F, 4.2 days below 50°F.  

For this test, that 10 lbs of ice had to cool the cooler and a lot of air, since there was nothing else other than the ice in the cooler. Considering that, the DAM 35 did pretty well, roughly matching the Yeti 35's performance in the Outdoor Gear Lab test. That 10 lbs of ice melted to not that much water -- it is maybe a couple of inches in depth. This photo also illustrates the panel divider slots.

Test 2

Stay tuned for another test that more closely follows the Outdoor Gear Lab test. Also, better placement of the thermometer.

Test 3

Stay tuned. This will be a test with way more ice.

Another VIP cooler from Germany is the Qool brand. They did some comparison testing too, and they filled the coolers very full of ice, and tested until the ice all melted. In that test, the Qool coolers retained a substantial quantity of ice at day 10. The Yeti 50 was the closest competitor, but having melt water by day 10.

Test 4

Stay tuned. This will be a test of the cooler in the wild, on a trip, with whatever hot ambient temperatures exist, either outside, or being baked in the car, and being opened and used. Let's see how the temperature holds up.