Sound Deadening & Tint

[thespacecowboy]

On my Dart, after replacing the floor pans, I installed 80mil Kilmat. It’s one of the many butyl rubber and aluminum sound deadening products out there. Primarily this was due to the fact that the exhaust ran directly under the driver’s feet, which made a drive quite uncomfortable after a while, or when going along the freeway. It additionally served the purpose of taking the rattle out of the sheet metal. I installed a couple of squares inside each door as well so reduce the rattle, as well as the hood and the trunk. I never removed the headliner and installed it in there.



It was highly effective at both heat and noise control, and I’m curious if anyone’s given any thought to adding any sound deadening products to the cab of the Slate. I remember seeing on a review from April 2025 of the SUV products that there would be no sound deadening on the ceiling of those, but in the maker it looks like there may be upholstery on the ceiling of the truck. Being made out of a presumably pretty thick piece of reinforced plastic instead of thin sheet metal, I’m not sure it’d do too much for rattling, but it may serve to reduce outside noise. One of the thicker acoustic foams under the headliner if there is one or behind where dash speakers might go could be of use.

As for tint, I’m eyeing one of the clear ceramic tints on the market for all four windows. They can really hardly be called tint, but they’re designed to reject UV, IR, and solar heat. It may help the climate control perform more efficiently since it won’t be battling the sun quite as much. Llumar advertises that their clearest one rejects 40% of total solar energy and their next step down rejects 60%. If that’s true, it may well beat stock. Not sure how much impact it would have on range, but maybe worth looking at.

 

[Kopsis]

One recent (2024) peer-reviewed study found windshield glass transmits about 40% of IR. Tempered glass in the other windows is about 30% of IR. Adding a "clear tint" film should stack with what's already in the the glass. So the 60% IRER film would bring side/rear IR transmittance down to 12% and front down to 24% -- a decent improvement. Check state laws -- some are really restrictive on windshield films.

However, it probably won't have much impact on range since if you're cooling the cab, the truck is probably also using the AC to cool the battery. But here in AZ it's worth doing just to avoid the second degree steering wheel burns when you leave your vehicle parked outside for more than 30 min in the summer

 

[phidauex]

Going between my cars I notice a big comfort difference between the MachE which has a full laminated glass and windshield with IR filters, stepping down to the Tacoma with a DIY tint job with a slight visible tint and strong IR filter, and the Prius, which is just 2006 factory glass.

The MachE and Tacoma are definitely more comfortable in hot weather, and they seem to cool down the interior faster. My arm feels like I'm going to get a sunburn when driving around in the Prius (though I think the natural UV blocking is enough to prevent that).

Whether it will improve range is debatable. This is one of those things where all logic dictates that it will improve range, but determining how much is virtually impossible because there are so many confounding variables.

Just on orders of magnitude, say you are cruising at 60mph, and the motor is drawing 25kW from the battery (a reasonable estimate). The HVAC is drawing is drawing 2kW keeping the cabin cool. That is 2.22 mi/kWh.

If your coatings drop the HVAC load by 25%, now you are drawing 25+1.5=26.5kW, which equates to 2.26 mi/kWh, a 2% improvement. Since some part of the year will be too cold for it to matter, and some parts of the year will be so hot it won't make much difference, maybe that nets out to an 0.5% reduction in kWh consumption over a year?

That is in that category of improvement that may be worth doing, and will help you out, but that you will probably never "notice". Though maybe one day you'll coast into your driveway at 1% SOC, and know that the coating saved your behind that day, since you would have been at -1% without it. But ultimately I'd do it for comfort benefits first, and efficiency second.

Sound deadening will probably help too. I know Slate is trying to do it right, but it is a low cost vehicle so I'm sure they won't spend a ton on NVH. The floor may not help much because that is where the battery is (rather than where the road/transmission/exhaust is on an ICE vehicle), but the footwells and doors where the tire noise comes in will probably help a lot, and possibly under the headliner and on the back wall to get the wind noise.

 

[thespacecowboy]

Going between my cars I notice a big comfort difference between the MachE which has a full laminated glass and windshield with IR filters, stepping down to the Tacoma with a DIY tint job with a slight visible tint and strong IR filter, and the Prius, which is just 2006 factory glass.

The MachE and Tacoma are definitely more comfortable in hot weather, and they seem to cool down the interior faster. My arm feels like I'm going to get a sunburn when driving around in the Prius (though I think the natural UV blocking is enough to prevent that).

Whether it will improve range is debatable. This is one of those things where all logic dictates that it will improve range, but determining how much is virtually impossible because there are so many confounding variables.

Just on orders of magnitude, say you are cruising at 60mph, and the motor is drawing 25kW from the battery (a reasonable estimate). The HVAC is drawing is drawing 2kW keeping the cabin cool. That is 2.22 mi/kWh.

If your coatings drop the HVAC load by 25%, now you are drawing 25+1.5=26.5kW, which equates to 2.26 mi/kWh, a 2% improvement. Since some part of the year will be too cold for it to matter, and some parts of the year will be so hot it won't make much difference, maybe that nets out to an 0.5% reduction in kWh consumption over a year?

That is in that category of improvement that may be worth doing, and will help you out, but that you will probably never "notice". Though maybe one day you'll coast into your driveway at 1% SOC, and know that the coating saved your behind that day, since you would have been at -1% without it. But ultimately I'd do it for comfort benefits first, and efficiency second.

Sound deadening will probably help too. I know Slate is trying to do it right, but it is a low cost vehicle so I'm sure they won't spend a ton on NVH. The floor may not help much because that is where the battery is (rather than where the road/transmission/exhaust is on an ICE vehicle), but the footwells and doors where the tire noise comes in will probably help a lot, and possibly under the headliner and on the back wall to get the wind noise.

You’re completely right on the math around total efficiency. It won’t do much to affect range, although it may do something. I think I could have phrased my thoughts a little bit better so let me try again.

I think the solar energy reduction of a window film and the potential heat rejection of a material like Dynamat/Kilmat may improve the efficiency of the air conditioning in achieving or maintaining a desired temperature, because the cabin volume would be better insulated and the system won’t have to compete as hard with solar energy wanting to bring up the temperature. My comment about range was more of an afterthought, because as you’ve pointed out it’d have next to no practical impact.

 

[phidauex]

You’re completely right on the math around total efficiency. It won’t do much to affect range, although it may do something. I think I could have phrased my thoughts a little bit better so let me try again.

I think the solar energy reduction of a window film and the potential heat rejection of a material like Dynamat/Kilmat may improve the efficiency of the air conditioning in achieving or maintaining a desired temperature, because the cabin volume would be better insulated and the system won’t have to compete as hard with solar energy wanting to bring up the temperature. My comment about range was more of an afterthought, because as you’ve pointed out it’d have next to no practical impact.

I agree with your thinking. If I get one I will end up tinting for sure, and depending on how good the stock condition is, installing some sound deadening. For me the benefits, in order, are Comfort, Appearance, Energy Efficiency/Range. The downside is $. Even if the range benefits are small, that is how you get improvements in this space, one half of a percentage point at a time!

 

[1yeliab_sufur1]

One recent (2024) peer-reviewed study found windshield glass transmits about 40% of IR. Tempered glass in the other windows is about 30% of IR. Adding a "clear tint" film should stack with what's already in the the glass. So the 60% IRER film would bring side/rear IR transmittance down to 12% and front down to 24% -- a decent improvement. Check state laws -- some are really restrictive on windshield films.

However, it probably won't have much impact on range since if you're cooling the cab, the truck is probably also using the AC to cool the battery. But here in AZ it's worth doing just to avoid the second degree steering wheel burns when you leave your vehicle parked outside for more than 30 min in the summer

any tint recomendations

 

[Kopsis]

any tint recomendations

The Llumar films that @thespacecowboy linked are really good. XPEL is another brand with an excellent reputation. SolarGard is a popular lower-cost option with reasonable performance but poor longevity (2 - 3 years typically).

 

[cadblu]

Where I live there are restrictions on the level of tint applied to to windshields; i.e. it must allow at least 70% light transmission (non-reflective tint allowed only on the top 6 inches).

The main glass area cannot be tinted darker. Same for front side windows (driver and passenger): Must allow at least 70% light transmission. This is the strictest and most commonly enforced area.

Same rules apply rear side windows and rear windshield for sedans, coupes, e.g. hatchbacks, convertibles, etc.

However the rear windshield and rear passenger windows of an SUV or van can be any darkness if your vehicle has functional outside rearview mirrors on both sides that give a clear view behind you.

Non-compliance may land you a ticket for illegal vehicle modifications and failure to pass the annual vehicle inspection. And yes, it happened to me. 👮‍♂️

 

[thespacecowboy]

Where I live there are restrictions on the level of tint applied to to windshields; i.e. it must allow at least 70% light transmission (non-reflective tint allowed only on the top 6 inches).

The main glass area cannot be tinted darker. Same for front side windows (driver and passenger): Must allow at least 70% light transmission. This is the strictest and most commonly enforced area.

Same rules apply rear side windows and rear windshield for sedans, coupes, e.g. hatchbacks, convertibles, etc.

However the rear windshield and rear passenger windows of an SUV or van can be any darkness if your vehicle has functional outside rearview mirrors on both sides that give a clear view behind you.

Non-compliance may land you a ticket for illegal vehicle modifications and failure to pass the annual vehicle inspection. And yes, it happened to me. 👮‍♂️

Luckily I’m in a state with no vehicle inspections. The Llumar tints I linked advertise themselves as clear instead of tinted and they pass through most of, as in 80+ and 70+ percent of visible light, so they shouldn’t cause too much of a problem. Of course I’ll need to actually lay eyes on them to see how dark they actually are and if it’ll raise any red flags, but I suspect something that’s letting 80%+ of light through and is the same on all four windows wouldn’t cause much concern.

 

[phidauex]

Summary of tint requirements by state. Can't confirm accuracy, but looks reasonable: https://greenfilmusa.com/pages/tint-laws-by-state

 

[KevinRS]

I kind of want to see what Slate ships with. Many of the images appear to have some level of tint.

 

[ReverendQ]

You’re completely right on the math around total efficiency. It won’t do much to affect range, although it may do something. I think I could have phrased my thoughts a little bit better so let me try again.

I think the solar energy reduction of a window film and the potential heat rejection of a material like Dynamat/Kilmat may improve the efficiency of the air conditioning in achieving or maintaining a desired temperature, because the cabin volume would be better insulated and the system won’t have to compete as hard with solar energy wanting to bring up the temperature. My comment about range was more of an afterthought, because as you’ve pointed out it’d have next to no practical impact.

Kilmat'd my F150 doors and that improved the sound from the stock system and of course deadened outside noise. Highly recommend it. Also had "clear" UV tint applied all around. "Feels" like it did something, but too many variables involved to really measure empirically. Can't hurt other than wallet. Neither should be appreciable to range although you can go crazy with the Kilmat/similar adding weight that may show up in reduced range I suppose.

Glad you brought the subjects up as reminders to something I will do with my Slate