We live in Northern California, in an area with a very mild climate. It rarely becomes too cold, and it rarely becomes too hot. Although we have a stove to warm up when it's cold, we don't have an air conditioner to use when it's hot, so we rely on fans. But when we go to bed, even if there is a fan in the room, even if the sheets are the lightest, it still feels uncomfortable. So, I went to find a solution.
I found this to be a very clever solution for $400, with an app-controllable fan that can provide room temperature or warm air under your sheets for extra comfort. It can certainly do the job, but at that price, it's a bit expensive, we don't need the heating function, and the application control just gold-plated Lily. However, looking at the entire setup from the perspective of my engineer, I think I can come up with something that can get the job done and is more economical.
In fact, it is not difficult. I went to Amazon again and found the key components:
This is the Apollo Horticulture 4-inch 190cfm duct fan, priced at $60. It is specifically used for ventilation in greenhouse settings, but can be used for various similar needs that require moving air through a duct system. It is quite quiet and moves a considerable amount of air (higher power devices are available, but this works well for us).
I started with this and an 8-foot-long flexible hose ($9), and then pumped in floor-level air under the sheets at the foot of our bed. It works well, but the end of the hose will move at night and make the overall cooling a bit inconsistent. So, I need to design a way to spread the cooling air and keep it in place.
My solution: a 5-foot-long 4-inch Schedule 40 PVC pipe (I bought it at the local Ace Hardware for about $15). I put a cap on one end, taped the open end of the hose to the other end, and then drilled holes along the length of the pipe to form what I call an "air sprinkler". There are even some engineering designs that involve the size and number of holes. I realized that in order to be able to deliver the same airflow generated by the fan, I need the total cross-sectional area of the holes to be equal to the cross-sectional area of the fan outlet (4 inches in diameter, or 2 inches in radius).
This is a very simple calculation. Since area = πr2, the output area of the fan is π x (2)2 or 4π, which is approximately 12.6 square inches. I chose a 3/8 inch drill bit, which can drill a hole with a cross-sectional area of π(3/8)2 or about 0.44 square inches. Using this drill bit, I can drill 12.6/0.44 = about 28 holes and maintain a fairly good efficiency. Then I just arranged an even pattern on one side of the pipe and imagined it facing our feet under the quilt, and then sprayed our feet evenly and filled the bed area with cooling air.
it works. It's really easy to use. We have spent a few very warm nights this month, even if there are floor fans in the room, we usually toss and turn, and every day of these nights is very comfortable. Even if the air under the bed sheet is only at room temperature, it can keep cool and comfortable well. Total price: about $85.
I'm still working on some details-like putting some bases on the pipe so that it won't roll at night, but this is just a small problem. Yes, I know it’s a bit silly to put a big plastic tube under the sheets when we sleep, but the point is that we sleep well—it's totally worth it.
This is a very clever device. Do you think it will be maintained over time?
How loud is the sound of the fan itself?
I also want to know if this fan is noisy. But this idea is really great!
How did this persist in the end?
We are still using!
I just made a similar device, but I used this duct fan: https://www.amazon.com/gp/aw/d/B06ZXWN3BG The cost is only slightly higher. When I bought it, it was 80 dollars. With a temperature probe (it is hidden under the mattress protector under our feet) and control unit, if we decide that we need a second fan, it can power and control both fans. As the bed gets hot, the fan blows faster! Still trying to figure out the best way to get air into the bed. I like your idea of pvc drilling. I have a section of flat tube, I can try a similar method.
David-looks great. I don't think it will be available when I build, but if I update, I will choose one of them entirely!
Thank you for posting this information! I am considering building my own. Still trying to figure out how to move it from under the bed to the head of the bed and be able to secure it in place safely and carefully. One method I am considering is to use pvc/vinyl gutter sheet. I believe there may be enough space between my mattress and the skirting board to install some downpipes. I also need to find an air filter for the pump. We have pets and I don't want to shoot pet fur balls onto the bed. Ha ha
An example of converting from a 4" circle to a 2"x3" downspout format: https://www.amazon.com/Amerimax-Home-Products-Flex-Drain-53227/dp/B008BGZ9CY/
Then expand https://www.homedepot.com/p/Amerimax-Home-Products-White-Flex-Elbow-37084/
Then it may leave a narrow nozzle or do something similar to https://www.homedepot.com/p/43-in-Low-Profile-Downspout-Extension-Kit-4601/303522071
All very good ideas! I just used a flexible hose improvised, so it was easy to move it, but after using it for a while, I realized that I needed to trim it to a certain length, otherwise it would swell due to the internal pressure of the fan.
As for the filter, this is a good idea-the easiest way is to put some fabric on the air intake. You just need to balance its filtering effect and the extra load it puts on the fan trying to suck in the air. good luck!
Charcoal 20 PPI Reticulated Polyurethane Foam Board
I am trying to find the person who created the bed fan on kickstarter. It is located on the floor and has an extension that extends upward and curves toward the bed. I am very angry. It took more than a year, even if it is brand new, it is not easy to use. Now it doesn't work at all. Frustrated customer.
Only when I searched for Kickstarter Bed Fan. 🙂
Great idea & thanks for sharing. I am preparing one for our bed. Quick note: In order to ensure that the total area of the holes drilled in the pvc pipe matches the area from the fan, I think your calculation is a bit off. If using a 3/8" drill bit, 3/8" is the diameter, not the radius of the hole. You may need some extra holes to keep the pressure constant.
My wife is always warmer than me, so this is a great idea! We are also paranoid about toxins. We have 100% natural latex mattresses and organic cotton sheets, so I don't plan to lay PVC on the bed between us. On Amazon, I found a 10-foot-long silicone hose with an inner diameter of 3/4 inch and an outer diameter of 1 inch (about 30 US dollars), and a collapsible silicone funnel with a length from 4 inches to 1/2 inch (approximately $5). Using the AC Infinity CLOUDLINE T4 in-line fan recommended in the comments above (now about $80, without thermostat) I used a closed metal hose clamp to secure the funnel to the fan. I cut off a little end of the funnel just enough to squeeze through a 3/4-inch copper fitting (Home Depot, $1) to connect to the 18-inch part of the silicone hose, which allowed it to rest on the floor without kinks. I think if I just bend it to the height of the mattress at the foot of the bed, the hose will be kinked, so I connected a 90-degree copper elbow ($2.50 Home Depot) and connected the 7-foot hose to bedside. I used a utility knife to cut small holes at even intervals on only one side (to cool her instead of me), and finally put a rubber plug ($1.50 at Home Depot). So if you are as crazy as we are, but still want a bed sheet fan, this is a good PVC or vinyl-free solution.
Cool! Can you add a link to the stated Amazon part? thanks
Silicone tube: https://www.amazon.com/gp/product/B079WRWH34/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Built-in fan: https://www.amazon.com/gp/product/B07JB292JC/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
I squandered directly from Bedjet and ordered an OEM air nozzle. The shipping fee is $19.
Note that the diameter of the hose connection is 3 inches.
Hello. I like this idea very much and don't think it is difficult to realize. My only question is how often do you kick the pvc pipe at the end of the bed? My boyfriend and I are both tall, reaching the end of the bed. I am worried that we will catch a toe in one of the holes.
We built it a few weeks ago and loved it. After some trial and error, it fits our sleep style. We both kicked and moved and pulled the blanket while we slept. We finally picked up our flat sheet, sewed a few ties, and then tied it to the fan at the foot of our bed. Then we use some straps to fix the PVC to the bed frame. It works miraculously. The sound of the fan is not louder than the window sash we went to.
This will be an absolute lifeguard when wildfires start and we cannot open the windows from the smoke. Seriously, my only complaint is that I wake up too cold sometimes!
That is amazing and wonderful. I am glad it is useful to you!
How about using pool noodles instead of PVC pipes?
I don’t know if you can get the same volume of airflow. Compared to the 4-inch PVC recommended in the project, pool noodles usually only have an open core of about 1 inch. However, you can use some non-rigid pipes, such as dryer vent pipes, and make it work.
What is the noise level of the AC Infinity CLOUDLINE S4 silent 4-inch duct fan beside the bed?
This problem is for those who have installed fans with manual control and temperature control units. I talked to the manufacturer and they stated that the advertised db level of <28 db is when it is installed in the attic of the duct, and the db level is measured at the ceiling air outlet instead of the fan.
Also want to know who installed the temperature control module-how does it work for your installation?
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