Tonneau Cover - How to Vent in Hot Weather

ember1205 · December 4, 2023

11 hours ago, MrLeadFoot said:

I used to live in the tri-state area near you, and while it got humid, it never got anywhere near the heat we get where I am now, and it gets hot for days on end in the summer. I've not measured, because I don't have a tonneau yet, but on 110 degree days, our roads are over 120 and they are not sealed. I wouldn't be surprised if the inside of a bed covered with a black hardcover tonneau easily hits 135+, and probably higher. Sure, I would plan on not carrying ice or plants on days like those, but I was wondering what some people in hot climates like mine do, if anything, when transporting stuff under tonneau, or just to let the bed breathe in hot weather. I'm trying to decide on a tonneau that best meets my needs, hence my question.

The road surface will attract heat energy from the sun and get really hot. Similar for the top surface of a tonneau. That heat will generally not radiate down into the bed nor will it have a significant impact if it did. There are all kinds of air gaps around the cover, tailgate, etc. where the heat will be able to escape fairly easily.

The interior of the truck will get much hotter because the sunlight passed through the glass to heat items inside of the cabin. If the tonneau were clear, you'd have a similar issue with the space under it.

The complete lack of any discussion around the topic while tonneau covers having been "a thing" going back decades" should help you to feel a bit more at ease about the potential of there being a problem.

My last truck was dark gray with a black tonneau. The one before was a medium gray with black tonneau. Both were hard covers, same manufacturer. I toted all kinds of things in the bed that remained there for days, weeks, or even months without being removed. There have been plenty of times that I dropped the tailgate in mid summer to load groceries or other items that I just bought - never felt any temp increase above that of the ambient air temp even on the clearest, most sunny of days.

I believe you will find that there simply won't be the sort of issue you're concerned about.

MrLeadFoot · December 4, 2023

9 hours ago, ember1205 said:

The road surface will attract heat energy from the sun and get really hot. Similar for the top surface of a tonneau. That heat will generally not radiate down into the bed nor will it have a significant impact if it did. There are all kinds of air gaps around the cover, tailgate, etc. where the heat will be able to escape fairly easily.

The interior of the truck will get much hotter because the sunlight passed through the glass to heat items inside of the cabin. If the tonneau were clear, you'd have a similar issue with the space under it.

The complete lack of any discussion around the topic while tonneau covers having been "a thing" going back decades" should help you to feel a bit more at ease about the potential of there being a problem.

My last truck was dark gray with a black tonneau. The one before was a medium gray with black tonneau. Both were hard covers, same manufacturer. I toted all kinds of things in the bed that remained there for days, weeks, or even months without being removed. There have been plenty of times that I dropped the tailgate in mid summer to load groceries or other items that I just bought - never felt any temp increase above that of the ambient air temp even on the clearest, most sunny of days.

I believe you will find that there simply won't be the sort of issue you're concerned about.

Thank you for such a well-put-together post.

One of the reasons I asked about heat under a tonneau is because I'm a semi-pro musician and transport related gear to events. One summer, my wooden drum shells split playing an outdoor event in the direct sun in 94 degree weather. During that same gig, our guitar player experienced the sun or heat tweak the neck of one of his guitars. Hard, multi-thousand dollar lesson learned for us about what the sun and heat can do, and after that gig, our requirements forever changed to us mandating overhead cover from the sun or we wouldn't play.

Although a tonneau would "shade" items from the direct sun, perhaps you can appreciate why I wonder how hot it can get under a tonneau cover, and how I might vent one, if possible. Thanks again for your thoughtful reply.

Edited December 4, 2023 by MrLeadFoot

ember1205 · December 5, 2023

9 hours ago, MrLeadFoot said:

Thank you for such a well-put-together post.

One of the reasons I asked about heat under a tonneau is because I'm a semi-pro musician and transport related gear to events. One summer, my wooden drum shells split playing an outdoor event in the direct sun in 94 degree weather. During that same gig, our guitar player experienced the sun or heat tweak the neck of one of his guitars. Hard, multi-thousand dollar lesson learned for us about what the sun and heat can do, and after that gig, our requirements forever changed to us mandating overhead cover from the sun or we wouldn't play.

Although a tonneau would "shade" items from the direct sun, perhaps you can appreciate why I wonder how hot it can get under a tonneau cover, and how I might vent one, if possible. Thanks again for your thoughtful reply.

I can completely appreciate why this is of interest to you... Do you happen to know someone with a truck that has a hard-cover tonneau on it? Or a couple of people with them, maybe different styles (folding versus roll-up, for example)? If so, maybe they would let you use their trucks for an experiment...

I have a couple of these: https://a.co/d/5yuDxpD

They will track min and max readings over a 24 hour period and they have magnets on the back. If you were to put one inside of the bed of a friend's truck for a day and the retrieve it, you would get a sense for just how high the temps went under the cover. I might do the same at some point, but I'm looking at a wait of at least six months before it's even worth thinking about around here. lol

Mshawn · December 8, 2023

On 12/3/2023 at 12:19 PM, MrLeadFoot said:

We get hot where I am. I don't like the idea of a sealed 150F degree bed. Surely that can't be good for anything you might have in the bed, including a rug or mat. I'm curious to know what, if anything, you all might do to vent that heat under your Tonneau, while driving and/or parked?

For example, I understand Retrax can be opened to any point along the track, but what about others that don't include that option? Have any of you come up with mods to accommodate for such venting? Like, has anyone come up with a way to drive with only one panel of a Bakflip open? Do those of you with multifunction tailgates just leave your inner tailgates open? Any constructive thoughts or suggestions welcome.

If you think this is a stupid question/topic, please feel free to not leave a comment, and just scroll on by.

I don’t think that’s a stupid question at all. I hadn’t thought of that and I want a hard cover on mine. I’m interested in find the answers to this as well.

MrLeadFoot · December 8, 2023

On 12/5/2023 at 1:10 AM, ember1205 said:

I can completely appreciate why this is of interest to you... Do you happen to know someone with a truck that has a hard-cover tonneau on it? Or a couple of people with them, maybe different styles (folding versus roll-up, for example)? If so, maybe they would let you use their trucks for an experiment...

I have a couple of these: https://a.co/d/5yuDxpD

They will track min and max readings over a 24 hour period and they have magnets on the back. If you were to put one inside of the bed of a friend's truck for a day and the retrieve it, you would get a sense for just how high the temps went under the cover. I might do the same at some point, but I'm looking at a wait of at least six months before it's even worth thinking about around here. lol

I, too, have months to wait until I might be able to measure temps under a tonneau in hot weather. I am wanting to install a tonneau, but don't want to make a costly mistake. On one hand, I can get a retractable like Retrax that will cover me (no pun intended) if I want to be able to open the top any little amount I want, should venting prove useful. But, if it turns out that venting only makes a marginable difference, I would end up spending extra money only to lose precious bed space to a huge canister, never mind the potential for more parts to break, and potential leakage through the slat joins over time. While a Bakflip is half the price, it requires being open at least 2/3 of the bed, unless someone on here has hacked a way to safely drive with the top folded 1/3 of the way open. If I have to wait until summer to take temp measurements that means another year of no cover for me. I was hoping to hear from folks who might already have experience in this area. I guess I could drive with the multipro tailgate open, but not sure if that's safe or even legal without a red flag tied to an oversized cargo item, let alone if I back up to a wall and not remember I left it open!

Edited December 8, 2023 by MrLeadFoot

MrLeadFoot · December 8, 2023

On 12/4/2023 at 2:52 AM, Jus Cruisin said:

Just what are you going to keep in the bed 24/7? I lived in Florida for nearly 30 years. Always had a truck and had some sort of tonneau on them most of them. The entire state of Florida is south of you.......uv index 11+ for months. Had Bedrugs in most of them, as well. The first one of those was in my 1999 F150 Lightning that also had a tonneau. I figured you would have figured out heat isn't an issue with my replies on your other thread.

Sorry, didn't see this post until just now. Whileni don't remember asking this question before, I will go hunt down the other thread now to see what you said.

MrLeadFoot · December 8, 2023

On 12/4/2023 at 4:05 AM, KARNUT said:

I’ve had all kinds, even a full shell. An avalanche now. No problem. We had 30 days over 100 degrees this year.

Somehow I missed your reply. I've not heard of avalanche and will look it up. Thanks for the reply.

Squatch fromGifted716 · June 13

This is a real concern. Those that don't think shouldn't respond. So I carry many products in before of truck as they are not legally allowed in the driver cabin. I am always looking 4 shade