Mack’s ThermaFit Review and Noise Reduction Test Results

Mack’s ThermaFit have been my backup earplugs for reducing low frequency noise (LFN) at night for more than two years now.

Lately, my go-to low frequency noise earplugs have undergone such substantial changes that they now feel like entirely different earplugs.

Consequently, ThermaFit have moved to the top spot. It’s good to have options!

In this post, we are looking at how potent these earplugs are at reducing low frequency noise and what you have to do so that they do more for you than only muffle higher pitched sounds.

I mostly use these earplugs during nights where I need to block the noise of trucks, music bass, stomping, generators, and hums from AC units, etc.

In a nutshell, Mack’s ThermaFit are excellent low frequency noise reduction earplugs for sleeping (detailed results below). I find them comfortable for sleeping on my side and can use them for a whole night without issues. 

How come we have porous, barrel-shaped earplugs?

ThermaFit are made of PVC foam, which is the same material the first foam earplugs to ever come out, 3M’s E-A-R Classic, are made of. In contrast, tapered earplugs made of PU are a more recent thing.

Classic are a bit shorter but have about the same diameter as ThermaFit. Classic are a bit stiffer though. Personally, I prefer ThermaFit.

But, E-A-R Classic, the original foam earplugs, still have a large number of fans all around the world! E-A-R did a lot of research on the ideal diameter for their barrels.

Both earplugs have an NRR of 29.

To avoid irritation and pressure points and test new models, I vary the type of earplug I use. When LFN is not my main concern, I like Moldex Pura-Fit (a tapered PU plug) a lot.

I know it is tempting to stick with one model, but to give your ears a break and to give you options, consider varying the type of earplugs you use as well.

Noise Reduction

Note: The following discussion pertains to my experience using these earplugs against everyday noise. (e.g., at night in my bedroom). It is not meant to assess suitability as a hearing protector. For hearing protection, please refer to the published noise reduction ratings and use instructions on the package.

I consistently get a reliable, deep seal with the barrel-shaped ThermaFit.

As mentioned in previous posts, when in doubt, I slam the freezer compartment door of my fridge to quickly determine whether I have got the insertion right.

It would be good if you could find a similar quick-assessment test in your home as well: something that makes a “bassy bumm sound.”

There are a few tapered PU earplugs with which I can achieve a comparable effectiveness against low frequency noise, but they are much less forgiving when it comes to insertion depth.

Moreover, when I insert these PU plugs sufficiently deep, they tend to be less comfortable than ThermaFit.

Please check my comparative review and test of other LFN earplugs if you are looking for alternatives or no-roll options for use during the day.

Here is how ThermaFit perform in my ears (against pulsed noises, 1/3^rd octave steps) and compare to my previous favorites (Flents Protechs Quiet Please before the recent formula change):

The higher the line, the better.

As you can see, in terms of noise reduction, there is not much of a difference between ThermaFit (red line) and Flents Protechs Quiet Please v1 (blue line).

Low frequency noise reduction (noise <=250 Hz) is mostly around 35 decibels for both earplugs, which is excellent. Quiet Please (blue line) appear to be a tad more effective in that range.

I believe that difference is real (in particular since the original QP performed even a bit better), but it is small.

ThermaFit very effectively reduce all noise, not only LFN. I am getting >30 decibels reduction across virtually the entire tested frequency range.

And, importantly, the noise reduction is even. These earplugs don’t shift the tonal balance by muffling higher frequency noises and letting more of trucks and low frequency hums pass through.

With most foam earplugs, even noise reduction is hard to achieve.

How effective are ThermaFit compared to my favorite tapered foam earplugs?

The following chart includes the noise reduction curve (again my ears) for one of my favorite tapered foam earplugs, Moldex Pura-Fit (NRR 33).

Against LFN <160 Hz, ThermaFit (NRR 29) are quite a bit more effective than Pura-Fit (NRR 33), which is why I choose “the barrels” when I am bothered by LFN.

Overall, however, Pura-Fit block more noise.

For example, barking dogs, shouting and crying, and honking all are more effectively reduced by Pura-Fit.

That said, ThermaFit help a lot against these kinds of noises as well, so you don’t have to forgo good overall noise reduction just to get an LFN benefit.

Pura-Fit are designed to have a higher noise reduction rating (33), so it is to be expected that they attenuate mid and high frequency noise more effectively; ThermaFit have an NRR of 29.

Insertion and Wearing Comfort

To achieve optimal low frequency noise reduction, ThermaFit need to be fully inserted. Here is a photo showing them in my ear:

“Fully inserted” looks quite deep, doesn’t it?

But you have to consider that these earplugs are shorter than most tapered earplugs, and my ear canal is quite long. I can insert them even deeper but then it becomes a hassle to remove them.

In any case, I can comfortably wear ThermaFit like this for a whole night.

When you insert them (like with any earplugs), you have to be mindful of your own ear canal, so don’t just ram them in.

I roll them into a tight cylinder between my thumb and index finger (using progressively increasing pressure), pull up my ear a bit to open the ear canal, and then slide them in.

For additional guidance, also check my post How to Put in Foam Earplugs.

They should go in easily.

At most wiggle them in, but don’t try to force them.

If they have expanded too much for them to go in easily, take them out and roll them some more to compress into an even tighter cylinder.

Initially, these earplugs may appear a bit stiff; they will become soft in the ear.

It is important that you take your time when rolling them up. If you compress them too fast, you might end up getting creases or deform them, which can lead to sound channels and poor noise reduction.

They are more forgiving than tapered earplugs when it comes to insertion depth.

But, if you only insert them 75%, chances are they will not offer even noise reduction across the frequency range, but only muffle higher-pitched noises instead.

If you want relief from stomping and heavy traffic, it is the last few millimeters that can make all the difference.

These earplugs exert less pressure in my ear than many other earplugs. They are, however, a bit denser than my previous favorite barrels, the original formula Flents Quiet Please (unfortunately replaced by the soft formula), in particular during the first night.

Note: The current incarnation of Quiet Please, “the soft formula,” exerts a lot more pressure in my ears than ThermaFit, and the soft formula doesn’t perform particularly well for me either.

Tip:

Should you find ThermaFit too dense, simply roll them up as you would for insertion but don’t use them right way; instead, store them in a container. The following night, roll them up again (their PVC foam requires less finger pressure the second time) and insert them in your ear.

Durability

Technically, these earplugs are disposable, so for hygienic reasons you would ideally use them only once. This applies in particular if you want to use these earplugs for hearing protection.

In the past, I too only used earplugs once and then tossed them out.

These days, to economize and reduce waste, I re-use them for a few nights, unless it’s for hearing protection.

I can use ThermaFit for a max of 5 to 6 nights. After that they don’t expand enough to completely seal my ear.

For optimal low frequency noise reduction, I may change them earlier, perhaps after only two days if they don’t perform anymore: As soon as they fail the fridge door slam test, they are out.

I know people who wash their earplugs, and I have tried to clean ThermaFit and other plugs as well.

But so far I haven’t been able to get them back to their original “springiness” and noise reduction performance.

This brings us to the end of this review. I hope it contributes to reducing stress and improving sleep for you!