Cabin Thermal Loss

[Nickage87]

So I noticed there is a lot of thermal losses because of:
- frameless windows
- glass roof
- lack of additional insulation around doors

With comfortable temps around 75F during winter I get 320-360 Wh/m. Have anyone tried insulating the roof? I found this product: Tesla Model 3 Sunroof Insulation & Battery Insulation: EV insulate wanted to check if anyone tried it and noticed significant improvement.

 

[mike123abc]

I get significant improvement in the winter with the heat off and the seat warmer's on. On really cold days wearing a coat in the car. This is only on long drives. If I am not trying to stretch the limit of the batteries, I use the cabin heat and not worry about the high drain.

 

[nvx1977]

the glass roof insulation would be something I'd be willing to try (though not at the price being advertised from your link). Battery insulation not so much. The site says it's better for short ranges:

Insulation helps it warm up faster and retain heat longer – especially useful when making a series of short trips.

I don't buy it. On a short drive and a cold soaked battery, there really isn't enough time to raise the battery temp. that drive is still going to be significantly nerfed by running a heater. Also based on the shape of those foam pads, you're going to take an aerodynamic hit on highway driving. That may cancel out any benefit of a warmer battery for both short and long trips.

If you need the best efficiency, I would reduce heater usage. I find myself comfortable setting ambient to 68F since I'm already bundled up for the weather when I get into (and out of) the car. You'll find that 68F will be a lot more efficient than 75F, esp in sub freezing temps.

 

[Atari2600]

From my own tests the parts you look out of were by far the worst. The top back and the very top had better thermals. This is my own car taken with my own FLIR camera. The panel is 33.6F and the windows are around 45-46 in the warmest areas. I forget what parameters I used for this. I did have the Tesla sunshade in the top. Bottom line, hard to insulate the parts you need to see out of!

This is my own conclusion. Please make your own.

 

[acarney]

That FLIR image (if fully believed) would lead me to think the windshield and side windows are the largest bridges for heat. They are significantly warmer than surrounding area and long wavelength FLIR does not pass through glass so we’re not seeing the INSIDE air temperature. That would make me think the glass is conducting heat from inside the car and radiating it off the outside of the glass.

I honestly can’t imagine the battery insulation doing much of anything. There is so much uncovered space and such a large mass with that battery (both in coolant and assembly materials and cells) that it’s a strong bridge right to the cold spots between. If it did anything, I would think it would be very little.

Again the glass insulation might help some, but slapping it on there isn’t going to be near as good as insulated glass. I would think there would be a small space between the glass and insulation sheet and convection would go to work. The glass will cool the air and that heavier air would “leak” out the sides and drop down in the cabin while hot air moved in to fill its spot and start to get cooled down by the large sheet of glass...

Instead, I think your best bet would be to precondition the cabin way longer than you would think you need. Instead of five minutes and jumping in as soon as the cabin air temp is up to 70, let it run for like 30 minutes. Yes you’re still using electricity, but drawing from the grid. Heat soak the metal, glass, and possibly even the battery. (It’s hard to track down for sure, but at least initially it was believed that the coolant loops were common between the battery and cabin heat exchanger.)

 

[android04]

I do have the EV Insulate roof and battery kits. I used the roof kit this winter, but I didn't notice much difference since I mainly did my daily drive to work. I do like the appearance of the roof kit (I still have it in and might just leave it on). I also almost always have my cabin temperature set to 68°F year-round. This part winter was pretty mild, so it was hard for me to casually observe any results of the roof insulation.

I don't have the battery pack insulation installed, and I'm not sure I will install it.

 

[Sam1]

That kit only covers part of the roof. It's silly IMO.

Get all of your windows ceramic tinted, including the windshield.

 

[Atari2600]

That kit only covers part of the roof. It's silly IMO.

Get all of your windows ceramic tinted, including the windshield.

I do not have anything on my windows. I do have triple pane double low-e windows for my house. Never noted a film that is low-e both directions.

 

[android04]

That kit only covers part of the roof. It's silly IMO.

Get all of your windows ceramic tinted, including the windshield.

It has 2 pieces and covers ALL of the "roof" parts of the glass. It covers the whole section above the front seats, and half of the rear roof glass (down to the part where the tint transitions into a lighter shade for rear visibility). So it basically converts the car roof into a more traditional one with insulated headliner.

I agree that it's more expensive than it's probably worth, but I also like the look of the interior better with it. Kind of like those people that prefer the look of Alcantara, even though I don't like it. As far as I know, tint will not insulate from heat transfer out of the cabin and will cost way more than the EV Insulate roof kit (especially if you get ceramic tint).

 

[HughH]

My problem is all the oposite than the OP. Our enemy in TX is the sun. I won't have a Tesla until next April but I already spoke with the Ft Worth SA and he told me Tesla makes a kit for the glass roof and it sells for around $90. He said it's easy to install. Of course, around here you just don't see a vehicle without tinted windows. I was thinking about getting the Y but that one has an even larger glass roof. We have a BMW 530e and like almost everyone around here we try to park under a tree, no matter how far it is when we go shopping.

 

[Atari2600]

My problem is all the oposite than the OP. Our enemy in TX is the sun. I won't have a Tesla until next April but I already spoke with the Ft Worth SA and he told me Tesla makes a kit for the glass roof and it sells for around $90. He said it's easy to install. Of course, around here you just don't see a vehicle without tinted windows. I was thinking about getting the Y but that one has an even larger glass roof. We have a BMW 530e and like almost everyone around here we try to park under a tree, no matter how far it is when we go shopping.

Although I have no window tint I do own both the top and rear window sunshade and it helps a lot. They call it front and rear but no it does not go on your front window. I did not bother taking it out this winter.

Tesla claims:

Constructed of lightweight mesh fabric with a collapsible rigid frame, the Model 3 Glass Roof Sunshade further reduces heat transmission into the cabin by blocking two-thirds of solar thermal load.

 

[Sam1]

It has 2 pieces and covers ALL of the "roof" parts of the glass. It covers the whole section above the front seats, and half of the rear roof glass (down to the part where the tint transitions into a lighter shade for rear visibility). So it basically converts the car roof into a more traditional one with insulated headliner.

I agree that it's more expensive than it's probably worth, but I also like the look of the interior better with it. Kind of like those people that prefer the look of Alcantara, even though I don't like it. As far as I know, tint will not insulate from heat transfer out of the cabin and will cost way more than the EV Insulate roof kit (especially if you get ceramic tint).

If you're only concerned with the roof, why not get the Tesla shades that cover the entire top and rear window?

 

[SlimJim]

I think glass roof provides greenhouse effect. Net effect of glass roof is thermal gain than loss. AC uses less power than heating element. So extra need for ac in summer due to glass roof is still fully compensated by saved energy due to greenhouse effect in winter.

 

[jerry33]

This really depends on what kind of winter you experience. If you are in Winnipeg or Saskatoon, the full insulation package would be a big help. Vancouver, Seattle, California--not so much. A/C doesn't use that much energy, so it's probably not worth it. If you park your car outside where it's hot, then sun visors and cracking the windows would do more than insulation.

 

[HughH]

This really depends on what kind of winter you experience. If you are in Winnipeg or Saskatoon, the full insulation package would be a big help. Vancouver, Seattle, California--not so much. A/C doesn't use that much energy, so it's probably not worth it. If you park your car outside where it's hot, then sun visors and cracking the windows would do more than insulation.

Of course I don't have any scientific proof as to which will do best. In Texas we need every bit of help in keeping the sun's heat out of the car. I can slide the protection from the sunroof on my BMW and leave the car under the sun for say, 30 minutes. You get in the car and if you touch the glass sunroof you can feel the heat immediately uncomfortable. With the protector in place it's not cool but not uncomfortably hot. Of course, if no rain is expected we also crack the windows open a few inches away from where the sun is shining. And we also tint the windshield and all the windows and still seek a tree's shade to park under.

 

[jerry33]

Of course I don't have any scientific proof as to which will do best. In Texas we need every bit of help in keeping the sun's heat out of the car. I can slide the protection from the sunroof on my BMW and leave the car under the sun for say, 30 minutes. You get in the car and if you touch the glass sunroof you can feel the heat immediately uncomfortable. With the protector in place it's not cool but not uncomfortably hot. Of course, if no rain is expected we also crack the windows open a few inches away from where the sun is shining. And we also tint the windshield and all the windows and still seek a tree's shade to park under.

Yes, though I don't have a tree and the tint person came down with CV-19 so tint didn't happen. The one thing I really miss on the X is the pano roof that the S had. You could open it up 15% and crack the windows and the car would stay reasonably cool (at least it stayed about the same temperature as the outside).

 

[DCGOO]

Cabin overheat will keep the cabin below 105°F. If I am parked for a couple of hours or less, I just leave the A/C running when I get out. You also can turn Climate on remotely when time to go to the car.

 

[HughH]

Yes, though I don't have a tree and the tint person came down with CV-19 so tint didn't happen. The one thing I really miss on the X is the pano roof that the S had. You could open it up 15% and crack the windows and the car would stay reasonably cool (at least it stayed about the same temperature as the outside).

Yes, sure. I could do the same thing with all the last 5 or six cars I have had. They all had unwanted by me sun roofs that I could tilt and let 105 degree wind come in. Guess you've never been in Texas during the long hot summers. Really delightful )

 

[jerry33]

Yes, sure. I could do the same thing with all the last 5 or six cars I have had. They all had unwanted by me sun roofs that I could tilt and let 105 degree wind come in. Guess you've never been in Texas during the long hot summers. Really delightful )

Take a look at my location (and my Teslas have always lived outside).