How to make the best DIY fresh air system on YouTube (great for apartments!)

This video will feature a step-by-step fresh air intake system build. I’ll also show you my technical drawings for multiple designs of different sizes, complete with all the measurements you’ll need to build your own DIY ventilation system.
These systems are best suited for those with a limited budget or those who can’t significantly alter their living space for whatever reason. Maybe you’re renting and your landlord doesn’t feel like spending thousands of dollars on a proper ventilation system. Maybe you live in the city and your outdoor air is particularly polluted.
I’ve been loving how much my designs improve my indoor air quality, and I know you will too!
DISCLAIMER: these systems absolutely have their limitations. They cannot regulate the temperature or humidity of the incoming air, and are thus not a high-performance solution. BUT, I’ll teach you some workarounds to maximize their utility.
-Intro: 0:00
-What are my fresh air systems? 0:28
-My technical drawings: 1:41
-The limitations of my systems: 3:23
-Materials list: 4:53
-BUILD VIDEO: 4:57
-The finished products: 17:56
-Performance data: 19:32
Necessary materials and tools (should cost $200-300 total):
-Pen or pencil
-4 mm coroplast sheets: amzn.to/4aAGmC5
-48" drywall T-square: amzn.to/3ytJ3I7
-Utility knife: amzn.to/3UOsaPO
-X-ACTO knife: amzn.to/4bxG1kZ
-Hot glue gun: amzn.to/44UkyQH
-Hot glue: amzn.to/3UUIfUb
-Lennox Healthy Climate MERV-16 filter: amzn.to/3WWCPuw
-2 pack of Filtrete 14x14 MERV 13 filters (I now recommend using a 1" thick filtrete instead of 4" thick filterbuy because filtrete has been shown to be superior even when thinner): amzn.to/450JKFh
-AC infinity CLOUDLINE LITE A6 fan: amzn.to/3RpVdIX
-AC infinity CLOUDLINE LITE A4 fan: amzn.to/3UQmBR6
Optional but sometimes useful:
-Coroclaw (For cutting coroplast, convenient but not necessary. Can just use utility knife): amzn.to/3Vhrt3b
-Short period repeat cycle timer (outlet): amzn.to/3WXiuoQ
-Non-toxic weatherstripping foam or tape
Above are affiliate links, which means I earn a small commission if you make a purchase through them. This helps support the channel at no additional cost to you. Thank you for your support!
Thanks for watching! Please like, subscribe, comment, and share with your friends and family.

[@kerrywang1126]

I'm still an advocate for filter before the fan. The filter also protects the fan from particulates and dust, which is especially important if the fan you're using is an axial fan (which I think your fan is). You wouldn't need to put the filter right in the window, given that you already built a housing for the filter that resizes its input. And you can always dampen the fan output or redirect it by pointing it upwards or something.

[@HealthyHomeGuide]

You have a fair point, and I do agree. I may make a future design in which the fan is after the filter. Though fan before the filter actually worked well in this context. And was easier to build and implement.

[@johnanon658]

@@HealthyHomeGuidealso, doesnt fan first make that pyramid you made a mold harbor w that damp outside air?

[@HealthyHomeGuide]

@@johnanon658 Good question. I didn't have mold issues with this device. Polypropylene is resistant to moisture. Many HVAC systems have a length of duct before the filter, it's not necessarily a problem to not filter air immediately as it comes in. One thing I also want to express is that it's definitely a more difficult build if you put the filter before the fan. Assuming you'd put the filter in the window (because otherwise, the system would take up tons of space), you need a much larger window insert, with a bigger cutout that'd be harder to get right. Not to mention that many windows aren't wide enough and don't open enough to fit the Lennox filter. Next issue with filter before fan: air comes at higher speeds out of a smaller fan than it does diffusing out of a larger filter. It's nice to avoid air blowing on people. For those reasons, I found that putting the fan before the filter was actually better in this case.

[@tlc1of3]

Thank you. Good info for improving air quality which is becoming a bigger issue every year!

[@HealthyHomeGuide]

Glad it was helpful!

[@gingerznz5742]

Great job mate

[@HealthyHomeGuide]

Many thanks!

[@winnerchild2854]

Awesome!

[@HealthyHomeGuide]

Thanks bud!

[@joefugate9338]

I like it. Thanks😊

[@HealthyHomeGuide]

Glad to hear it 🙂

[@davidhoover2446]

Great video man! That Lennox filter the by far the best on the market. I use that on my HVAC systems air handler. It’s awesome. Positive Energy has a podcast called “The Building Science Podcast.” You’d love the podcast. I actually have been contemplating the same things. I want to make a more compact one that can maybe mount to a wall with a flex duct going to the window to keep it out of the way. Living down here in Florida the fresh air has to be paired up with a dehumidifier as well. Keep up the good work!

[@HealthyHomeGuide]

Thanks so much David! Absolutely, that Lennox filter is top tier. It’s by far the best filter I could find. I checked out the titles of the episodes of that podcast you recommended and it really does look perfect for me. A wall mounted filter unit would be really interesting! I haven’t personally found flex ducting that doesn’t smell terrible - could you let me know if you find a decent one? For compactness, my other designs (#2 and #3) in this video do the trick well I think, but I like your idea of mounting them to the wall somehow instead of using the floor for support. P.S. I’ll be thinking about dehumidification strategies this summer!

[@Flash1857]

Awesome videos

[@HealthyHomeGuide]

Thanks!

[@ZenonDorinPower]

Would be interesting to have a video about home water filtration as well, not just for drinking but also for the showering water which otherwise would introduce some amount of chlorine (and possibly many other things) into your skin.

[@HealthyHomeGuide]

That’s a great suggestion, thank you!

[@johnanon658]

@@HealthyHomeGuidethe key to RO is to remineralize the water. Also you can filter water w cedar branches, or other type of fresh cuttings.

[@gadget2622]

Cool video! Thinking of installing my own ducted filtered air intake in my own place and stumbled on your video. Just FYI if you want a better cleaning product than vinegar, you should look into making your own hypochlorous acid. Non toxic, easy to make, and extremely effective as a cleaning agent.

[@HealthyHomeGuide]

Wow, this is fascinating! HOCl is apparently an endogenous substance in all mammals that is effective against microorganisms? That’s so cool, I’m gonna look into it.

[@gadget2622]

Yeah, it's pretty cool! Obviously need to be careful with the pH and free chlorine amounts, once the pH of your solution gets too low you start producing chlorine gas, but once you have a good recipe down it's a great cleaner. Plenty of research into using it for all sorts of things. Lower concentrations of Cl have been used for wound cleaning and there has been some work into investigating the effect of aerosolizing it to help with COVID treatment/prevention because it appears to not only kill harmful foreign micro organisms, but apparently also causes the mucus membranes to produce more n-chlorotaurine (i think, bit foggy on this detail, read the paper a while ago), I believe as a result of the increased concentration of free chlorine. And that stuff is also supposed to be a great anti-septic compound. Which is another pretty neat detail! But yeah, just an all around cool chemical, great for washing food if you're worried about fomites and bacteria and what not. @@HealthyHomeGuide According to a few studies breathing a misted/fogged/aerosolised sample can improve allergy symptoms and help with easing inflammation of the respiratory tract. But I personally haven't tested that yet.

[@HealthyHomeGuide]

@@gadget2622 Incredible! That is so impressive! A cleaning agent that is actually potentially beneficial to breathe in? THIS I have to look into. Thanks for your comment!

[@jvistas6074]

Is there a 'simple' recipe available?

[@krashanb5767]

I need to build something like this for a truck sleeper. Preferably 12v powered 😊

[@HealthyHomeGuide]

I love it

[@minutemansports2685]

Love this idea. I live in a colder climate in Canada would you know of any inline heaters that could be added so I could be bringing in heated air in the winter? Hard to keep the windows open in the winter.

[@HealthyHomeGuide]

Glad you like it! Good question. I haven’t explored the world of DIY inline heating because I’m a bit wary of its safety. Alternatively, have you heard of energy recovery ventilators (ERVs)? If you haven’t, they’re worth looking into. I have a video on how to do a DIY installation of an ERV.

[@minutemansports2685]

The safety thing definitely crossed my mind as well. And yes I have heard of ERVs. Do you know what affect they have on air pressure in a house? I live in an apartment and recently got new neighbors who smoke and found it wafting into my washroom. I patched up the holes in my washroom and started using the washroom fan less as I found it was creating negative pressure in my washroom and drawing in the smoke from the neighbors unit. My temporary solution is leaving two small windows open in my living room and having a floor mounted air purifier to draw air in from outside and create an overall positive pressure in my apartment thus pushing out unwanted smells from the neighbors. I found this video because I like the idea of bringing fresh filtered air into the house just hard to do in the snowy winters. Do you find with the timer you set up that you have major temperature changes in that room?@@HealthyHomeGuide

[@HealthyHomeGuide]

ERVs are what's called balanced ventilation, meaning they intake fresh air and exhaust stale air simultaneously, and thus don't affect the pressure in a house. They basically allow you to take in fresh air that's not too hot and humid in the summer and not too cold and dry in the winter. I feel you on that smoke situation. I've experienced something similar and it was maddening. Unfortunately, unless your home is very airtight, it's actually pretty difficult to positively pressurize a home. For the typical home, you'd need around 230-350 cfm to do so. That's more than people think. I suppose it could be accomplished by a system like the one in my video, but you'd need to turn it on a higher speed to bring in ~300 cfm, which would be quite problematic when it's hot/humid or really cold. The timer I set up definitely did help with those issues on extreme days, but I was running it on the lowest speed which only delivers 55 cfm. Another issue for your situation is it won't always be running if you use a timer, of course.

[@vladislavmolodtsov4795]

Man, I cannot find any merv 13 or merv 16 filters in my country. Can I use HEPA 11 or HEPA 13 instead?

[@jvistas6074]

Great system, but in my case I need just the opposite, I need a system that will take 'damp' air out of my unfinished basement. Do you have a design for that?

[@HealthyHomeGuide]

A dehumidifier would be perfect for removing dampness from your basement. I have a video on setting a great one up.

[@AnnainAwe]

I'm thinking your design might help me with making an off-gassing room out of a bedroom. I'll also be putting a ceiling fan in the room. ... It's turning out I need to have three of the four bedrooms off-gassing 🤯. The mattresses my two sons purchased are much too toxic to be tolerable with my MCS. .... The house has central AC, I could really use some coaching 🙏🏼

[@HealthyHomeGuide]

That’s awful! I feel your pain. The neighboring condo just sprayed Lysol in their place and now mine smells like it. I have MCS as well. Ventilation (bringing outdoor air inside) is indeed the best way to dilute concentrations of VOCs like from mattresses off-gassing. My device in this video could be useful to you as a short term solution (if it’s not too hot/cold/humid outside of your house). As a future goal, you may want to consider having an ERV installed in your home. That way you can ventilate safely no matter the outdoor conditions!

[@michaelgray5547]

Thank you so much for the very helpful video! Are you aware of any commercial products that offer similar capabilities as your window ventilator? Like you, I suffer from mold allergies and also live in a very humid area in Portugal where mold spores are everywhere. I would like to filter the outside air before it comes into my apartment, but I do not have much faith in my DIY abilities so am looking for some sort of retail filter-fan that can fit into an acrylic window insert (like yours), but having trouble finding anything designed for this sort of thing...

[@HealthyHomeGuide]

I’m glad you appreciated my video! HVACquick has some inline filter boxes that are similar, but lower MERV, and Martinson Manufacturing makes window inserts. Hopefully those can be shipped to Portugal. That being said, I feel that a simple fresh air intake would bring in too much humidity (which leads to mold growth) and heat for you. A better option for ventilation is an ERV (+dehumidifier) since you live in an area that gets humid. You could also try using a ventilating dehumidifier, but that may bring in too much heat. Anyway, if you’re interested in learning more about ERVs/dehumidifiers, I have a few videos on them. Good luck!

[@johnanon658]

Why would you not want to have a little positive pressure in the house to keep outside air from leaking in??

[@HealthyHomeGuide]

Some people might. It depends. For instance, in the winter, it can be risky if you humidify your house. Because you'd be pushing humid air behind your walls, which can cause mold growth.

[@johnpiek2750]

👾 Woah that is some great simple effective design/materials. I wish I saw this video before the Canada fires smoke impacting my area in New York state. What devices have you been using to monitor the PM 2.5 before and after in your rooms? Also, will that cloroplast/glue breakdown from being near window/sunlight? 😼

[@HealthyHomeGuide]

Thanks so much! This design is indeed very helpful for filtering out particulate from wildfire smoke. I used the Dylos DC1100 Pro for particulate monitoring. Hot glue and corrugated plastic are not significantly affected by sunlight. In order to become pliable, hot glue must reach temperatures much higher than those that would come from sunlight filtering in through a window. Coroplast is also resistant to that sort of heat - until it reaches a temperature of 600 degrees F, it will not break down.

[@davidtieu4920]

Likewise, during the wildfires, I actually taped a merv14 filter and a charcoal filter to a box fan and stuck in the window and sealed it up with cardboard. It allowed the house to be better ventilated, but then there was no exhaust and I found CO2 buildup in other areas of my apartment with a CO2 meterm I've been trying to figure out how to do what you've accomplished by literally "f*cking around"...but this channel really brings it all together in clear concise ways and takes all the experimentation away. Very inspiring channel @healthyhomeguide !

[@denizerkan5632]

What prevents insects from getting sucked into the fan ?

[@HealthyHomeGuide]

The window screen. It catches most insects before they enter the fan. Just have to clean it every so often. If you can’t use a window screen, that’s actually okay. You’ll just maybe want to vacuum insects out of the filter every couple months during warm periods.

[@denizerkan5632]

Hi - what kind of weatherstripping foam did you use? You mentioned "non-toxic" so I am curious.

[@HealthyHomeGuide]

Hi! The foam I used is unfortunately not available anymore. I’ll let you know if I find another good brand.

[@denizerkan5632]

What thickness was it ? Also , I think you mentioned that the foam in part corrected a mismeasurement, but wouldn’t I want foam regardless to ensure a tight seal between the chloroplast and the filter frame ?

[@KageBlink]

You got any ideas if this could work for Canadian weather? Snow and stuff lol

[@HealthyHomeGuide]

Absolutely. When I filmed this video, I lived in a mountainous climate colder and snowier than much of Canada.

[@KageBlink]

​@@HealthyHomeGuide Amazing! Going to make this for my bedroom, and the big HRV for the living room and kitchen. Or should I just make two of the small ones? Coroplast is expensive up here, the core looks like it'll take a lot of sheets

[@AnnainAwe]

​@@KageBlink Check for purchasing coroplast with sign making companies for best new purchase prices. Also you can repurpose old campaign signs.

[@VenturaIT]

carbon/charcoal filters only filter about 9% of VOCs at most and this includes huge carbon filters with 25 lbs of carbon in it, they help improve odors but don't really work for safety and health, so if you have a problem neighbor or live in an area with high VOCs outside, this is a bad idea, the only solution when you have gases (VOCs) outside is to move, outdoor TVOC should be around 0 ppb with no visible sources of pollution... just .0001 ppb of ethylene oxide, for example, exceeds the EPA's lifetime cancer risk limit.

[@HealthyHomeGuide]

Agreed. My stance is that activated carbon is not nearly as reliable or effective as people think it is in the context of air purifiers and VOC removal.

[@VenturaIT]

@@HealthyHomeGuide our testing of the #1 rated consumer air purifier showed 9% also for a huge consumer carbon filter with 25lb of carbon, same result... our lab with one of the world's leading expert with a PhD in Chemistry has spent decades testing filters with the same results, about 9%... that's not good enough for me when you are dealing with class 1a carcinogens, so the only option is to move... even more than that when you are dealing with class 1 a carcinogens they will stick to every surface and the filter surface so the filter will then become a source of trace amounts of carcinogens, and if it's blocked by the carbon, then later, like you said, it can re-release the carcinogens back into the air when it gets full or the humidity, temperature, and pressure are just right and then your carbon filter starts to poison you... this is not medical advice.

[@JoelKenningtonJDKW]

Do more

[@HealthyHomeGuide]

Thanks! Anything in particular you want more of?