DIY Radiant Blockout Curtains for Stealth Camper Van Conversion

In this instructable I'm going to share with you how I made radiant blockout curtains for a stealth camper van conversion. These curtains keep the van cooler during the day, warmer at night, and block all light from inside and outside the van.

These curtains were made for a minivan conversion so that I could stealth camp inconspicuously but the same curtain making process will apply for any van or vehicle conversion. Follow along to learn how to make your own!

As a disclaimer, I'm no sewing expert by any means. If you have any suggestions for how to make this instructable better, feel free to suggest them in the comments!

I'll also admit that these curtains do take a while to properly make. However the initial cost and upfront effort is absolutely worth it when you are stealth camping later on. Quality curtains that reflect radiant heat will keep your van a more comfortable temperature throughout the day. Plus these curtains block out all light meaning you can inconspicuously stealth camp anywhere without anyone knowing that you're inside your van. And for days when you want to sleep in a bit longer, these curtains are great for delaying sunrise until that moment when you're ready to finally wake up. All right, let's begin!

Step 1: A Little Theory, Approximate Costs, and Hacks If You're Short on Time

Before diving into the project, I think it's worthwhile to understand why you might need radiant blockout curtains. If you've ever come back to your car on a hot summer day, opened the door, and felt a rush of hot air escape from inside your vehicle then you're intimately familiar with the problems of radiant heat.

For a quick primer on heat transfer, know that there are three kinds. Radiant heat is energy transferred via electromagnetic waves (in this case, the rays of the sun). Conductive heat is energy transferred by direct contact (think touching a hot stove or a holding a cold snowball). Convective heat is energy transferred through the circulation of liquids and gasses (why a breeze feels so refreshing on a hot day). This link provides a good breakdown of the three types of heat transfer as they apply to vehicle conversions.

While glass is a fantastic conductive insulator, its transparent properties make it a very poor insulator for radiant heat. By using a material that can reflect electromagnetic radiation (aka the sun's rays), we'll be able to better insulate all the windows in a van against radiant heat gain and loss.

Depending on the size of your vehicle and the number of windows, the cost of this project will vary. To outfit a standard minivan with curtains for all of the windows behind the driver's cabin, the cost of materials was about $60 USD and approximately 30 hours of time (measuring, making templates, purchasing materials, learning to sew, re-measuring, creating prototypes, pinning fabrics, sewing curtains, installation). If you are already proficient at sewing, I expect this project could take far less time. That being said, don't underestimate how much effort is required to create a quality finished product. The effort is well worth it, I just add this word of caution to advise you to not leave this project until the last minute.

If you are running short on time and need something quickly, you can get by with thrift store bed sheets cut to size and taped over the windows for privacy. For a radiant heat barrier, use either emergency blankets or reflective building insulation over the windows as well. This solution may be effective but takes a frustratingly long time to properly put up and take down while also making it obvious that someone is camping inside the vehicle. If you have the time, I strongly suggest making custom curtains instead.

If you don't have access to a sewing machine or are currently traveling, you can cheat by using staples to hold the fabric together. It's by no means the best solution but can get by in a pinch.

Step 2: Notes on Attachment

This is one area of the design that still needs to be perfected. I used a combination of curtain wire and velcro to keep my curtains flush to my windows but found this solution to be less than ideal for a few reasons. The biggest trouble I had with this method was that the adhesive backing on the velcro had a tendency to melt off the window on hot, sunny days. I think this effect was amplified due to the curtains re-radiating the sun's rays back through the window. I could have used a more permanent method for attaching the velcro to the windows but thought it would be unsightly to permanently glue large pieces of velcro to the inside of my windows. I also found it somewhat difficult to locate suitable attachment points for the curtain wire. In places where I could screw into the metal frame of the van, it was easy. In other places I had to screw into plastic trim which was prone to stripping out and leaving unsightly holes on the van's interior.

If I were to do it again I would try to use small rare earth magnets to hold the curtains flush to the windows of the van. Gluing small magnets to the vehicle's interior or even its non-moving windows would be minimally obtrusive and provide a repeatable location for attachment. Magnets could be sewn into the fabric or used externally to pinch the curtains to the magnets surrounding each of the windows.

If you are unsure of which method will work best for you, I suggest prototyping with inexpensive fabric for your most difficult window and seeing what works best. When you find a workable solution, proceed to replicating that approach for your final curtains.

Step 3: Supplies and Tools

Supplies:

These curtains are a three layer construction with a thin black outer layer, reflective middle layer, and thick inner layer. The black outer layer is dark enough to disguise the curtains from casual passerby but thin enough to let the sun's rays pass through and be reflected back. The middle layer is reflective and made of an emergency blanket-like material. The thick inner layer is standard blockout curtain material used for homes to prevent light from entering through windows. I found that reflective radiant barriers such as emergency blankets and summertime windshield sunshades are not 100% light blocking. To ensure that no one could see when I had lights on inside my van, I chose to use a blockout curtain. If you don't need your curtains to be completely light blocking, you can substitute this inner fabric for any other of your choosing.

All of the fabric materials and sewing supplies can be found at your nearest fabric store. The emergency blanket is usually available at outdoors stores, big box stores, or online. In my case, I used a silver metallic-colored tablecloth I found on clearance at Target. I found it worked just as well as an emergency blanket at 1/3rd the price. Depending on the attachment method you choose, you should be able to find these supplies at your fabric store, big box store, or online.

I chose 100% polyester fabric materials for their flame resistant properties. I occasionally cook inside my van and wanted to minimize the risk of fiery mishaps. Polyester is by no means fire proof, but it is slower to ignite than cotton and generally melts when exposed to flame. While I never anticipate having open flames close enough to my curtains to cause problems, I view a melting curtain to be a safer failure mode than a fiery one. If anyone has a better suggestion for a common, fire-resistant fabric let everyone know in the comments section!

The materials used are given below.

black polyester dress fabric
emergency blanket
blockout curtain fabric
thread
sewing pins
attachment method (curtain wire, magnets, velcro)
self-tapping sheet metal screws (optional - for curtain wire method)

Tools:

You'll want a few basic tools for this project and one specialized tool: a sewing machine. Chances are you'll have all the basic tools. For the sewing machine, I used one at a local makerspace. If you don't own one yourself, ask friends and relatives if they have one you can borrow. Similarly you could reach out to local schools and universities in case their industrial arts or home education departments have one you could use. There's always the option to purchase one too, but if you're doing the whole van life thing, chances are you're downsizing and not looking to bring along a sewing machine. For the utilitarian van dweller, a stapler and some patience could prove a functional albeit less polished alternative to sewing these curtains. I would not recommend sewing these curtains by hand; it'll take far longer than learning how to sew on a machine or roughly stapling the fabric together.

For tools you'll need the following.

tape measure
pencil
paper
tape
straight edge
scissors
sewing machine
drill and drive bit (optional - for curtain wire method)
super glue (optional - for magnet or possibly velcro method)

Step 4: Measure Windows and Make Templates

This first step is one of the most critical. Let your measurements be short and defeat the purpose of this project before sewing a stitch. Measure too long and spend far too much on fabric and materials. Spend time on this step to make future sewing work much easier.

You'll want to have your tape measure, pencil, scissors, tape, straight edge, and paper for this step. I chose to use large sheets of butcher paper but thin sheets of flexible cardboard or printer paper taped together works too.

Begin by measuring the approximate size of each window and jotting down the largest dimensions. Cut your butcher paper to size or tape your printer paper together to create a rough template for each window.

Bring this template into your vehicle, tape it to the inside of your window, and use your pencil and scissors to make incremental corrections to the size and shape of this template. After a dozen or so iterations you should have a paper template that perfectly fits inside your chosen window. Repeat the process for each of the other windows for which you plan to make curtains.

Step 5: Plan Material Usage

This step will depend a bit on which attachment method you have chosen (curtain wire, magnets, or velcro). Curtain wire requires about 5cm (2in) of extra material be added to the top and bottom of each curtain. Velcro and magnetic attachment methods can generally be the same size as the window itself or slightly larger if you are attaching the curtains to the vehicle's frame rather than its window directly.

In any case, lay out your window templates on a large table or floor and arrange them in a nesting pattern with slight gaps of about 2.5cm (1in) between each template. Try and create a rectangular layout with a width of between 110cm and 150cm (45 to 60in) since this is the width range of most bolts of fabric. Once an efficient rectangular layout has been arranged, make a quick sketch or take a photo of the layout and note its length and width dimensions. You'll need these dimensions for when you go shopping for fabric.

Step 6: Purchase Materials

Find suitable materials from your local fabric store. I recommend purchasing locally rather than shopping online for something as personal and aesthetic as curtains. The best way to know what a material looks and feels like is to actually handle the material in person! So head on down to the fabric store and begin browsing the aisles for suitable materials.

For the black outer layer I used a thin polyester fabric I found in the dress making section of the store. I held the material up to the lights and saw that the weave was loose enough to allow light to easily pass through the material. For the light blocking inner layer, I went to the curtain section of the store and found a neutral gray blockout material that closely matched the interior trim of my van. If you don't need your curtains to be completely stealth, plenty of other fabrics with more exciting patterns are available that block a significant amount of light.

Once you've settled on materials, double and triple check that the width dimension of each bolt of fabric will accommodate your curtain layout from the previous step. Then get the corresponding length of fabric cut, purchase matching thread, and pick up some sewing pins if you don't already have some. If you're new to sewing or just a bit rusty, consider purchasing a bit of inexpensive fabric to practice on. The thin outer material I purchased was 40% off so I purchased a bit extra to practice sewing.

Purchase an emergency blanket from an outdoors or big box store. If that is not an option, find one online. Note the unfolded dimension of the emergency blanket and compare to the area required for all of your curtains. If you're unsure of how many you'll need, purchase an extra. If you find you don't need it for the project, you can pack it along with your first aid kit for when you're out traveling.

Step 7: Cut to Rough Size

Use your layout sketch from Step 5 as a guide for cutting your fabric and emergency blanket to roughly the same size as each window. Once the appropriate amount of material has been allocated to each window curtain, you can begin assembling the layers and pinning the curtain.

Step 8: Pinning It All Together

Using your templates from Step 4, begin pinning each curtain together. If you plan on attaching the curtains using curtain wire, pin some of the extra material at the top and bottom of the curtain so that it makes a loop (third picture). If you are embedding magnets into your curtains, consider leaving a small section unstitched where you might insert magnets later. With velcro, I suggest sewing the curtain first, figuring out where the velcro needs to be placed to make the curtain lay flat, and then sewing the velcro on later.

When pinning the three layers of fabric together, I found it easiest to first place a few pins to prevent the layers from moving relative to each other and then proceeding to carefully pin the edges. I folded the raw edges of the fabric into the middle of the curtain to provide a more finished look. You can also choose to simply sew the pieces together and clean up the raw edges a bit with scissors after you are done sewing. Either way be sure to check your pinned curtain against the template before beginning to sew! As they say measure twice, sew once...

As a word of encouragement if you're new to sewing like me: it can take a frustratingly long time to pin everything up properly. But don't despair, it's worth the effort! Properly pinned curtains were a breeze to sew. It's like most projects really, spend 80% of your time setting up and the other 20% actually doing the work will be relatively easy. Cut corners on set up, and you'll spend the same amount of time or more frustratingly redoing sloppy work.

One tip I picked up while practicing was to place pins so that they are easy to remove as you go. I placed mine facing toward the presser foot of the sewing machine so that as I advanced toward the needle, I could pull them out from behind. If I had placed them the other way around, it would have been difficult to remove them without interfering with the presser foot and sewing needle.

Step 9: Sew It Up

Depending on your level of comfort with a sewing machine, this will either be the easiest or most daunting step of the entire process. I came to this project with very little sewing experience and in a day and a half found that I had gained a new skill and quite a bit of confidence. Once you learn to sew, it's actually pretty fun and super rewarding! If you're new like I was, start by searching for how-to videos regarding your particular machine. This isn't an instructable on how to sew, but I'll go over a few basics.

The sewing machine uses a needle to weave two pieces of thread together. The upper thread starts on the spool and is wound through a series of tensioning mechanisms before being thread through the machine's needle. The lower thread you'll need to wind onto a spool called the bobbin which sits below the presser foot and under the needle. Refer to your sewing machine's instruction manual and related how-to videos to get your machine threaded properly.

If your machine allows it, you'll also want to set it up to do back stitching at the start and end of your stitches. Back stitching prevents the thread from unraveling over time. I used four back stitches at the start and end of each curtain.

Once you've practiced enough to gain some confidence, begin sewing your curtains together. Don't worry if your curtains aren't perfect, you'll get better with practice and no one but you will ever see them. They are meant to be stealth curtains after all.

Step 10: Installation

Depending on your chosen method of attachment, begin the installation process.

If you are using curtain wire, find appropriate attachment points above and below your windows. Use a drill to drive in the self tapping screws. Stretch out the curtain wire between the attachment points and cut to length. Feed the curtain wire through the fabric loop, attach the screw eyes, and secure using the sheet metal screws.

For velcro attachment, stick small pieces of velcro along the edge of your curtain and position it over the window so that no gaps remain. Mark the position of the velcro pieces on both the vehicle window/frame and on the fabric. Secure one side of the velcro to your vehicle and sew the other side to your curtain.

While I have not yet used magnets for attachment, I think they might prove the best option. Similar to the velcro method, you'll want to position multiple magnets along the edge of your curtain until no gaps remain to let light in. Consider taping the magnets to the window glass or vehicle frame for alignment purposes and then bonding them permanently with super glue or two part epoxy once properly positioned. Avoid hot glue as the high temperature might demagnetize the rare earth magnets. Attach the magnets to the inside of the curtain by sewing around them completely or consider using the magnets as a way to externally pinch the curtain fabric to the vehicle. If anyone has suggestions for successfully using magnets to achieve a flush fit to the window, let everyone know in the comments section.

Step 11: Testing and Results

Since this project is utilitarian in nature, it's pretty important to know how well the curtains work. To initially test them out, I placed a cup of water in the van with a thermometer sticking out and left all the curtains drawn. I parked the van in an unshaded parking lot, let the afternoon sun bake the outside of the van, and checked on the thermometer a few hours later. The reading was 30°C (85°F). I then opened all the curtains and within 30 minutes the temperature had risen to 35°C (95°F). While not the most controlled experiment ever devised, I think it adequately illustrates the concept that radiant curtains do help regulate the temperature within a vehicle. If you're considering converting a vehicle of your own, radiant curtains are a good step in properly insulating your mobile abode.

Step 12: Conclusion

So do they work? Based on my experience, absolutely! After road-tripping around for a number of weeks, I can tell you that radiant curtains will definitely help prevent your vehicle from becoming a toaster oven. That being said, they only delay the inevitable and slow the rate of heat gain inside your vehicle. When possible it's usually best to park in shade and keep windows down to get a cross breeze flowing through the vehicle. But if you do need to have your windows up and keep heat out, these curtains do an awesome job!

Plus they are incredibly effective at blocking out light too! Check out the pictures of the van at night with all its interior lights on. With the curtains drawn, no one can tell from the outside that anyone is inside. Stealth mode achieved!

Step 13: Final Notes

For those of you following along closely, you'll notice that I didn't make any curtains for the front of the vehicle. Instead I chose to use a standard reflective windshield sunshade and a simple fabric curtain to separate the driver cab from the back of the van. I found that the standard windshield sunshade helped the vehicle blend in better with other parked vehicles and that the simple fabric curtain would block any remaining light. You could certainly make radiant blockout curtains for the cab partition but I found it wasn't as important as making them for the windows themselves.