Home built passive solar air heater

Bozeman, Montana Building and Remodeling Contractor Peter Brown describes a simple home built passive solar air heater that uses only the buoyancy of heated air for circulation.

[@tomlampros7122]

I built hundreds of these collectors in the early '80s, in upstate NY, and they worked well. The original design, similar to the one shown here, used 1x4 for the perimeter frame, but quickly found it didn't stand up to the heat, warped and twisted. We changed to aluminum (Al) C channel , lined with thermax. The back wall was thermax, skinned with an Al sheet to act as an absorber. Over that we put 2 layers of 2' wide Al house screen, top to bottom. We installed Al standoffs to supprt a gridwork of 2'x2' glass, mounted to bars that were attached to the standoffs and C channel, held in place with butyl tape. The pass throughs, orignally a passive system with a plastic flap (as shown in the video), stagnated too much air and the collector would overheat. We began installing 6" ductwork, wrapped in fiberglass, at the top of the collector, run through the attic, to a diffuser on the north side of the house, with a squirrel cage blower in line. The intake at the bottom of the collector was a flap covered vent.which worked well because at night the cool air would push the vent shut. After much success with this design, we augmented the system with a heat exchanger for summer use and when the house was satisfied. Plumbing was run from a storage tank tot he exchanger, installed in a thermax box. A pump was controlled by a thermostat in the house, and thermostats in the exchanger. A controller would turn the pump on when the house was satisfied, or when the duct temp was right and the tank needed heat. The whole system without the water part sold for ~$6000, and ~$10k with the water heater (1983 USD).

[@A_Pa-Plainjane]

thank you kindly for that. I would like to see that setup. I did want to note, as modest a cost that was, my goal would be to make an even less expensive system, if that is possible, using only convection or thermo-syphoning. Of course if a home was designed well enough, that could be done. but not the way we currently design and build our mac-mansions.

[@inhocsigno9151]

Good info, thanks. I would like to try something in my home.

[@rickewachewski3392]

this is the best solar heater I have seen so far. I built one for myself but I made a few changes, here is what I did.. I have a 20x30 ft shop and I put a 8x18ft panel on the south wall. the 20 ft wall faces south. I put a 2 inch opening a the top and bottom , the plastic flap at the top opening works very good. Their two things I did differently, (1) I used a plywood backing on my solar frame and I took of the siding off my building so I could attach the solar frame to my wood wall studs. I then painted the plywood flat black, I did not put the screen in because it just does not work (a screen has maybe a 25% surface area and it slows the air flow as well , the plywood has 100% surface area and does not restrict air flow) . I covered the panel with clear plastic sheeting (the same as they use for sky lights on steel buildings) . (2) I built a header box over the 2 inch opening on the inside of the building, and mounted a 12 inch furnace fan at one end of the box. I put a heat switch inside my solar panel and attached it to the black plywood, it turns on the fan when it gets110 degrees and shuts of at 90 degrees. the solar panel cost me $400.00 ca. On a -10 f day out side the inside temp will start at 32 f in the morning and rise to 65f . On warmer days out side the inside temp will not drop below freezing. I live in southern Manitoba canada

[@A_Pa-Plainjane]

Bravo, Rick- sounds good. Having the plenum (header) part seems to help a lot, I think. Several (wise) folks have come to the same conclusion if you search youtube a little. I do not know why this idea is not more widely used.

[@rickewachewski3392]

@@A_Pa-Plainjane I have been using my system for three years now, it has been working great. People has asked about condensation , I have had none that I can see. Because I use a fan to force the air through the system I get great air movement inside the shop, floor temp is the same as ceiling temp. day time temps get to 65 to 75 f in side the shop on sunny days in dec and jan with out side temps around -10f , my panel is attached to wall so in the summer time it gets no direct sun lite, it produces very little heat in the summer this design will work on any size shop.

[@tzmdomeguy]

Excellent heart! I have two suggestions for anyone building such a project: 1( Under the clear coragated plastic, first install a simple flat sheet of heat resistant clear plastic - this will give the effect of a double pane window for better heat retention 2( The seal for the back flow preventers must be a tighter seal NOTE: keep in mind that during the night this extra air space helps to retain heat that would normally radiate out of the wall of the house! COOL ...I mean WARM !!!

[@817tempestinateacup]

Human ingenuity will be the only method for humanity to survive the technological adolescence we are currently experiencing. Kudos on your efforts and thank you for inspiring my own projects :)

[@pinarellolimoncello]

You're not wrong, technology is presently being used to drive us all into digital / binary dystopia. As my teenage son correctly pointed out , one persons Utopia (endless cheap travel and holidays ) is another persons dystopia (low paid baggage handlers, bus drivers, air pollution etc) . Until everyone comprehends 'All for one and one for all ' we are looking at deeply divided planet/ society not to mention poor old mother nature. To conclude technology use...an aeroplane can be used to drop either bombs or drop seedlings that would generate new forests, there is no balance / compromise to be struck as the devil would have people believe, you cant half drop a bomb on someone or half spoil the planet from greed, stupidity and overdevelopment. As it says in Proverbs, Where there is no vision, the people perish.

[@JohnBau]

I built two of these on the south side of my 90-yo home in 2009, with modifications adapted for a massive masonry wall. On sunny days (which are the norm here in NM) they heat the entire main floor to 75-78ºF. I added two small fans on the outtake of each to increase efficiency. IMO Gary Reysa's technique is the best way to do solar air heating. The central stream boiler was relegated to backup, and my nat gas bills went from $300/mo to $60/mo.

[@tchr2249]

In 1988, while Prof at MO Southern State we built a similar solar panel and used 4 layers of black screen wire spaced 1/4 apart, total thickness 1 inch and we could get 115 degree temps out of the solar panel [80 degree difference @ max] with double glazing. Cost was very nominal then and lasted nearly 8 years before having to change the clouded glazing to improve efficiency again. --- More need to use this idea. It works WONDERFULLY! -- The old shop tchr of 40+ yrs.

[@swilhelm3180]

Was it sensitive to wind? And how many hours a day did you get lots of warmth in the middle of winter?

[@pinarellolimoncello]

@@swilhelm3180 Probably more than you...

[@swilhelm3180]

@@pinarellolimoncello I'm not understanding your reply to my questions. Or was that an attempt at humor?

[@pinarellolimoncello]

@@swilhelm3180 Maybe I mistook your question for cynicism , if I did I apologise but as you know there is NO shortage of the spawn of satn on the internet that take great pleasure in raining on somebody else parade. Back on the subject of the air source heat collector, I think they will all vary in different latitudes, Thing to do would be build a small pilot one, see how it performs then go bigger if it works.

[@swilhelm3180]

@@pinarellolimoncello That makes sense. Thank you.

[@GadgetAddict]

This is the simplest design I've seen to date. Very clever.

[@stanisawwarwas2169]

Okej

[@copperclockmaker]

I built something similar to heat my shop in the winter. It is only 8 foot by 8 foot. I use a 20 inch box fan to pull air out of the collector, controlled by an attic fan thermostat to arm the fan and a baseboard heater thermostat to control the heat. BTW this is in New Mexico.

[@miicar204]

I have built 4 of these heaters and they work very well without fans. I am glad you have baffles at the top, because as you know if you omit this step your solar heater will run backwards at night and suck all your heat back out. I put baffles on the top and bottom. It does not reverse with these baffles and it heated the entire suite as long as the sun was out.

[@backyardbraaapn1017]

mil car why the fuck did you feel the need for this redundancy? They went over this in the video

[@angelaj8958]

I built a similar heater on a house near KCMO almost 35 years ago. The design used Thermax insulating board painted black and tacked up on the siding, and also had the clear glazing and thru-wall vents. It heated the entire house. In summer, it had vents on the standing side walls to prevent unwanted heat in the house. It had fewer vents, and had regular register vents that you could close or open as needed.

[@jackrodgersjr]

Tongue in cheek idea: every Florida driver knows what it is like to open and sit in a car that has been left in the sun. So get long lengths of flexible schedule duct and run it from car to home.

[@denisecomeau6847]

When we bought our house in 2003 ,we were looking for ways to heat cheaply. After reading the Mother earth news article about the Montana fella,hubby built our first one around 2009 for $100 and mounted it on the outside of his office wall.Installed a small computor fan register and it would click on when needed. The comp fan gave out after 1 year.-that cost was $100. But the collector is still there and heat drifts in just by natural means. Top and bottom holes are in place. I think its time to install another little fan.This is on our south side and works no matter the outdoor temps.

[@denisecomeau6847]

Now here we are in 2021. I want to add a big collector to the big living room wall...

[@karenleeklee3627]

FANTASTIC variation of a trombe wall system, which I think almost every building can use for supplemental heating. And so much more cost effective in the initial building. LOVE it. Thanks so much.

[@GlasbanGorm]

I trust a home builder named house. 110%

[@Mbenham04]

Very nice. I cant wait to find some time in my life to make one.

[@VostockREvolution]

never, enjoy capitalism, slave

[@VostockREvolution]

you only must work and buy, nothing of create and "think" things, understand? and die fast, that FMI cristine lagarde say that you will be a problem when you get old..

[@gavinyates9189]

Wonderful, if it'll work on a small-scale it will work on a big scale.

[@aaronvallejo8220]

I made 6 inch and 4 inch R24 insulated plugs with brass handles riveted to duct caps sealed with aluminum tape. When it is cold those holes will loose a lot of heat. Solar heaters do work really well to heat houses.

[@TheMyopath]

It looks like the Trombe wall designed by a french engineer in 1930's.

[@claudedesaulniers2300]

Very good. I would also put mirrors on the ground.

[@thorthunder3227]

maybe some old tv magnifiers also would throw lot of heat

[@SolarCompanies]

It looks interesting by the looks of it. I think solar air heater is efficient and cost effective. Thanks for sharing this cool video guys!

[@singularity844]

This only works while the sun is shining. A good augmentation would be to use coiled tubes and run water through it (probably anti-freeze). Then you can use a tank size of your choice as a heat sink, and you can use the tank's heat for probably a few hours after the sun sets. At the end of the day, you're just blowing air across hopefully hot coils of tubes. The circulation pump clicks off the moment the collectors temp drops below the inside temperature.

[@just-dl]

I think a thermal mass (concrete, stone, brick, water tubes) would be good for capturing more heat, adding to the heat transfer into the moving air. great concept. I think it can be applied anywhere that direct sunlight is available.

[@DeterminedDIYer]

You may not want it to get too hot though. Risk of fire.

[@zakarygardner5158]

So would black bricks in the heater work better or black pipe heating water barrels inside?

[@just-dl]

@@zakarygardner5158 the screen is going to allow fast heat transfer, both absorbing and releasing...adding black bricks behind this would be an excellent way to increase the ambient temp inside the systems, and also provide more surface for the temperature transfers to occur on. I'd consider your idea very advantageous in a particularly area...at first light, the mesh will start to absorb/release heat; the bricks will take a while to warm up. So the initial benefit of the screen is felt, while the benefit of the brick is delayed; however, the bricks will continue to radiate warmth after the sun goes down, which the screens will not do. if you want water pipes to augment the air warming, i think the bricks are better...bricks don't leak! :-) however, if you want additional hot water...then black water pipes are a great idea. My suggestion would be to use the black water pipes to absorb what heat they can, the store in a tank which is then augmented by an on-demand water heater. Let's say that it's not 100% in terms of hot water supply, but, gets a tank up to 85* or 90* (F). The on-demand system then only has to elevate from 85/90 to 125/130...instead of from 60/65 groundwater temps. That'll require less fuel on the on demand system's part. in the summer time, with extended heating times, you may not need the on-demand at all. If you're looking to do something like this, good luck with it!

[@justgivemethetruth]

This is a very simple elegant and clever design ... but I' thinking two problems. 1. All the heat is up at the top of the room and you need some kind of power for a fan or to mix the air so that while it is surely effective it is not strictly passive. 2. What do you do when the room gets hot enough? Turn off the vents, but then the side of the house is still heating up, and I wondering if you can really tune the overhang so well that you get no heat in summer.

[@NJRenewableEnergy]

I like the idea, I just wonder about heat loss at night or cloudy days. The flap is not going to prevent conduction heat loss. So what are the btu loss at these times, versus the gains.

[@michaeldvorak8140]

When working in solar heating in 1981, I had first hand knowledge of the remarkable amount of heat developed by this simple design. The panels we sold and installed were of the newest design and made in Israel 🇮🇱. We demonstrated these panels at a solar fair being held in San Francisco California and wowed the crowd.

[@b57ecv]

Great design, I'm thinking of using the same on a brick house here in England.

[@konasan]

I live in Hawaii. I have a south facing wall that is "single wall" 3/4" redwood painted white that gets warm to the touch not long after the sun hits it in the morning. In the winter the house is in the low 50's(F) but warms to 60-70's later in the day. The house is unheated. I am after heat as soon as I can get it but don't want it after 10am when the eaves start to have effect anyway. I want the heat fast and not stored for later. This system looks perfect. My only concern is a way to clean the space. I'm thinking hinged panels (like doors). I'll update this comment after it's built if I live long enough.

[@glassblastcollision]

If you duct this heat into the back of a clothes dryer set to " no heat "and if your lazy hanging clothes on a line then you can dry your clothes with this system idea. Most of the electricity is used by the element in a dryer not the tub rotation motor . So even in the summer time when it's not being used to heat your home you can scavage the heat from your passive solar heater. You will also find that for the most part your home is hotter inside then outside at night time and most of the heat is at the top of the room so at night the pop can solar heater will cool down and draw hot air from the ceiling go out to the collector and then cool air will naturally drop back in at the floor inturn cooling your space a couple degrees.

[@bodryn]

Now we're getting somewhere! This is what I need on my garage, except that part of the time the sun is partially blocked by the house shadow. Might have to see if I can use the south half of the garage roof.

[@citroenraspdideveed9243]

I have a question. After some time don’t you get mold in the box? Logically the water in the air condenses inside the box when temperatures drop outside the box. This will make the box wet inside leading to mold. When the box is used again to blow hot air, the spores of the mold will end up in your heated area. Do you have this issue?

[@TheOldGuyPhil]

This does not happen. The intense heat and UV sterilizes every sunny day. There is very little nightly condensation unless your dampers are not sealed properly.

[@justgivemethetruth]

I imagine they are depending on the black screen to shield the side of the house from the sun so that it does not directly conduct to inside and only heats the air which will only convect heat into the house, so you only get heat when you want it, and not like in summer or something. If you paint the house black you open that area to heat all the time, or at least more often.

[@EastTexasEquity]

I like this system much better than the painted tin cans.

[@NARM82]

It's certainly much easier to build.

[@LK-pc4sq]

yup...much easier to build all right. I dont think screen should be used. Simple corigated steet painted flat black will work.

[@miicar204]

I used corrugated black steel panels and a glass front. I do not understand the mesh either.

[@putheflamesou]

what about folding foam painted black...or ordered that way. Covered with greenhouse film.?

[@KyAl2]

I wonder if the black mesh can be rolled up like a window blind during the summer? If one were to paint the wall black you would have to cover it and corrugated panels you would need to make them removable.

[@terryorourke9632]

Great really professionally done Terry

[@solarheat2978]

I have two thoughts on this design. Paint the exterior of the barn black to absorb more heat, and cover the collector during warm months to avoid sunlight exposure and to prolong the life of the polycarbonate.

[@MrKenjiro2012]

+Solar Heat Great idea, but who want's black walls?

[@solarheat2978]

+MrKenjiro2012 I only meant to paint the section of barn behind the collector Black. Not the entire barn.

[@MrKenjiro2012]

Ahh, but still wouldn't that stand out? Not trying to give you a hard time, because it's a great idea, just I know if I did something like that, my wife would disapprove lol.

[@twiztidbagz]

+MrKenjiro2012 my thought would be to hang stone tiles of any color on the back, stone absorbs heat like a sponge, and would retain heat into the night.

[@MrKenjiro2012]

Bob Villa ok

[@hanseich]

Would installing a window not have been more effective? I understand that it would have been more expensive (in my view, not having windows in a south site, just shows that building was not built with the sun in mind in the first place), but as I understand, the thermal siphoning acts negatively at night, those flaps look like they might hinder some of it, but they also hinder the flow of warm air.

[@tzmdomeguy]

I love this installation - it is excellent for post construction but just think of what you could do if it had been integrated into original construction. Advantages below: 1( the collector could be the exact size of the entire wall 2( no siding necessary - just be sure that your exterior clear covering is as reliable as the siding would be 3( Windows could be framed to penetrate "collector wall" therefore maintaining the view NOTE; Keep in mind that this system must shut down in summer.

[@jonathanhale2669]

This is a Trombe wall- you guys might want to credit the inventor (or inventors, if others) of the concept

[@savingenergyaroundho]

its very interesting video.. and I pick up some great info about solar.. thanks..

[@CJWilliams]

Absorber plate area is critical and Long term performance of glazing must also be considered. Screen vs. other absorber plate options will determine efficiency. Heat loss offsets from reverse thermosyphoning will also need to be mentioned.

[@paulwood4769]

simple and smart ... fantastic

[@HarmJan71]

Looks like a Trombe Wall to me.Developed in 1960 by a French Engineer Félix Trombe.

[@m1aws]

Its less than a Trombe wall. He used a block wall to act as a heat sink to keep the interior temperature more stable an the front section like a conservatory. Also an overhead Sun shade to stop overheating in high Summer.

[@justgivemethetruth]

That's a fair comment, and good point. I think at minimum they need some kind of real vent that can close at night or when it is cold out. The way it is the interior or the room is separated from possibly freezing outside night or winter air by just that small flap ... that's seems a little ridiculous?

[@mjakersusmc]

In your video, you mentioned that during the Summer, the higher angle of the Sun produced no unwanted heat. I'm no scientist, but I would assume that statement would not be the case in all locations. I know that my home gets a whole lot of sunlight on the South facing side of my home during the Summer months. Do you know if they (or anyone else) ever integrated a way to redirect the heat during that time of the year so as to not incur higher electric bills in the summer while trying to cool their home?

[@player101player101]

I guess u can make the flaps, closing the openings in the wall movable. Upper flaps opening outwards and upwards, lower flaps opening outwards and downwards.. u know like hinges... then if u have the corresponding openings in the heat panel frame itself u can do two things at the same time : open the flaps - they close the panel airtight and direct heat inwards; close the flaps - they seal the home and the heat from the panel just goes up and away, and colder air moves in from below. So u use the heat in the winter and just let it go in the summer :)

[@miicar204]

On my second new solar house I had five foot overhangs on the south side. We had no sun in those collectors in mid summer, but had a bit of overheating in spring and fall. We just opened a few windows.

[@joejane9977]

just cover with white sheeting

[@pencilme1n]

I keep active, wear the right clothing and have thick duvets for the colder months.

[@trmwyldshade1482]

I question the effectiveness of the "garbage bag" plastic backflow valves. Material seems far too thin… Any suggestions?

[@Ladosligese]

as long as its airtight no air can go back

[@csmrfx]

One would think the thermal loss from the holes through the wall in the periods of no/low thermal radiation greatly surpass the thermal input form the panel.

[@R_Alexander029]

I live in Australia and essentially, I want to achieve the opposite; I want to use this technique to cool down a house.

[@mandolinic]

I've been looking at a few of these different designs now. I like the basic idea but I've a few misgivings: 1. I don't like the general idea of air going through a hot environment and then being ducted into the building. A common design is to paint the interior of the box, or use a black painted material. However, you've no idea what molecules the heat is going drive off the painted surfaces, etc, which are then going to find their way in the lungs of the occupant. As far as I can see, no one ever gives this a single thought. 2. The warm air usually ends up at ceiling level, whereas it's my feet that get cold. Don't you just create a terrific temperature gradient inside the room, with hot air at head level, and very cold air at foot level?

[@mikegibney2898]

Mandolinic 1. The avg house has air ducts that collect and distribute way more nasties than a box with paint in it would. 2. Basic understanding of thermal dynamics would explain why heat goes up. If your toes are cold run radiant heat through your floors. Just be prepared for the cost of it

[@puddingpimp]

I imagine the paint would give off no more vapors longterm than any other time you paint the interior of your house, but if it's a particular concern, you could use several other items as a thermal mass like: rocks in a wire cage, solid granite (expensive, but pretty), stained black concrete, black cast iron, etc. The essential elements are converting the solar radiation to heat, and preventing the convective losses that would occur if you just painted the wall of your house black (pretty ineffective to negative effect). Using a stone thermal mass has the advantage/disadvantage that the heat is stored and smoothed out, so you get heat in the evening when the sun is down, but then you don't get the heat in the early morning unless you make the mass massive enough to smooth out a 24 hour cycle, and that's like tonnes of material required (but done in some passive heat commercial buildings).

[@rstevewarmorycom]

Unless you have hydronic floor heating heat always goes to the ceiling anyway by convection. The outgassing, if any, is cooked out of it within a few days anyway. Engine/exhaust system flat black doesn't seem to outgas, It's metallic in a high temp epoxy.

[@thorthunder3227]

That is right on the spot. store the energy all day while still using it and then also put some pipes in for hot water also.

[@robertmoore1215]

The advice you got with exhaust system flat black is spot on. Once the heat cures off the voc's, it's a non issue. I'd be more concerned about the type of insulation used for the box to retain the heat. Styrene or polystyrene for instance would likely have an off gas throughout it's shelf life because it's not intended to serve these purposes. As for the heat going to the ceiling, that could be easily remedied with ceiling fans tied to a solar panel as they would operate in tandem with one another in prevailing weather. HVAC & fireplaces need blowers/ ceiling fans to distribute heat too. Even if you never spent the money there, you'd still be saving 50% of the btu cost of heating up the whole space, and overall greatly diminishing the need to run primary heating sources during daylight hours. This project sounds like folks should experiment on a detached shed/garage for a year or two before attempting to apply it to an active living space.

[@61riaz]

Wow really great idea

[@thorthunder3227]

Has anyone ever thought about using old concrete blocks as the tubing and heat storage inside an insulated box. I would insulate the box with fiber underneath a heat reflective foil against the blocks and cover with some nice sliding door glass doors on the 2x10s x8 foot long or longer box. I think this is heavy but look at the thermal storage it would have for overnight. Is this ok or is there a problem more doing it with concrete blocks?

[@RJKYEG]

This would be a good option for unheated garages, unfortunately mine doesn't have a good wall for this.

[@porkytorkwal]

Gravity doesn't have to "push" on anything. The accumulation of air that is more dense will displace air that is less dense. If that wasn't the case this system wouldn't work either.

[@jackrodgersjr]

What about the buildup of black mold inside the boxes and dust and little creatures. Does your design provide a method of opening the boxes and cleaning them? The window screening would be a great collector of dust, etc. I have an allergy to dust mites and am particular concerned about rugs and poorly maintained ac systems. Anytime I stay in a motel I have to remove the filters and clean them in the bathtub as they are usually filthy as are the fans and vents. Dust will naturally accumulate inside the boxes. Adding latches and hinges so the boxes could be opened and sprayed clean would be an essential design extra for me.

[@familyoffour8020]

Interesting concept, but there is no thermal barrier - only a simple back flow valve of sorts. I don't see how it would prevent thermal transfer during times of cold exterior temperature and zero sun IE: in the winter, at night, and there would likely be condensation issues as well. Should there not be a thermal barrier device that is activated during these times to keep out the cold or am I missing something?

[@shermanhofacker4428]

Close the bottom openings to augment the flaps.

[@porkytorkwal]

Yes, but the air loses heat as it moves away from the heat source. It does not stay forever heated, it cools and falls. Establishing a cycle that is perpetuated by the newly created hot air that follows.

[@larryjohnson6579]

Very impressive. Is that a garage or similar building? I'm curious about how to finish such a system on a residence. Would it be compatible with a building that also has fa orced air HVAC, or would the forced air system interfere with the passive solar system?

[@orowizard1369]

Not very impressive. Costs about $350 plus labor, saves $350 to $400 per year. I was expecting way better performance in my mind. On a helpful note, would using mirrors to reflect more light onto unit make a lot of difference? Possibly doubling output?. Would mirrors would reflect better than snow?

[@davehanlon2920]

That's not bad 1 year return on investment and they mentioned the snow reflects light

[@magna59]

Nice to see the 1st years saving payed for the equipment . So would it be of value to add double glazing for the full effect , and some solar storage ( heat exchanger & water ? ) for those winter short days long nights .

[@martinspru6871]

If you put a large window, you have the better effect, Sun will Heat the floor in the house. If you do it like here, you have to make it mouvable. So you can adapt to the sun and you gain 25%.

[@SougoUltimateSadist]

having brick home and cold winters and doing any slight modifications cost too much, dosent help that morning sun is blocked by the barn ): . Having this would save up a ton on firewood and prevent half of house being at freezer temperatures.

[@leeanndonnelly-gabrielli9445]

What about heat loss at night? I have a cabin in Maine and will be adding a solar heating product this year but fear too much overnight heat loss. I like the idea and it looks great.

[@rehanawebster3981]

Im a big fan of mother earth news

[@xzibit8614]

Those thin flaps don’t provide much R value to prevent heat loss at night.

[@NorthShoreHomes]

This is exciting and affordable. So on days where its cloudy and rainy it's not an option? My daughters are working at the womens and childrens showers in a refugee camp in Greece and one of the problems is that there is not heat to dry the towels or when it is cold. They use a clothes line in the basement to hang the towels and something like this may be feasible. I sent them your video with the hope that maybe they could put together something like this to help. or any other suggestions ?

[@porkytorkwal]

So in your world there is always a cold wind beating down on you. Air couldn't possibly move laterally because there is no such thing as pressure. The animation in this very video (which you concur with) demonstrate that.

[@robertstephens7400]

suggestions..... more inside pics. is the wall sheetrocked/finished inside ? Is it a garage or house ?......The vinyl flaps are just ridiculous how about something significant instead of a kitchen garbage bag for a vent flap ?....... even Tyvek would be an up grade ....maybe some double wall polycarbonate on a pivot with a thin rod through it?

[@linuxxr]

add some vertical copper pipes with focused/unfocusable magnifying glasses and there u have it.....

[@CrapPolice]

Missouri wind and solar has a more compact similar design that puts out the same amount of heat.

[@porkytorkwal]

Additionally, maybe you just don't get that the intake on the other video was a floor level. The solar unit itself was the only thing on the roof.

[@PeterQBrownDesign]

You are right about that. If you go to build it solar.com and pose that question to Gary Reysa. Gary is the original designer. Really enjoyed your site by the way!

[@figman4890]

Why is the house wall not also painted black? Would this not also help to capture the solar energy as well as the screen?

[@tylerknowles6128]

Does this black aluminum screening produce as much or more heat than using cans? It seems like there's a lot neglected surface area to collect heat.

[@robertmoore1215]

I also just saw a youtube contrasting performance between steel cans vs aluminum downspouts painted black. The downspouts won by nearly 20 extra degrees in an experiment done in new mexico.

[@thudthedestroyer515]

Is there any scientific data being collected? What is the CFM being produced by the passive air-flow? What is the heat volume per hour being produced? Finally and most importantly, what is the cool jazzy music at the beginning?

[@keimo2007]

Douglas Moseley it's passive, there is no airflow!

[@davidproskin1752]

of course there is air flow... its a passive convection system

[@thudthedestroyer515]

Of course there is airflow...It is just not being generated by some mechanical method. The air is moving by differential temperature gradients and atmospheric pressure.

[@thudthedestroyer515]

Do you have any quantifiable data? What region of the country are you in? This may work in some areas, but not in others. Suburban areas of Chicago for instance are not replete with greenhouses as they can be difficult to justify cost vs. Benefit.

[@VostockREvolution]

cfm depends of season and if it sunny day or not and hour, because some hour have peak direct sun on the system, there is many variables

[@popoqwer]

Exquisite

[@thorthunder3227]

Does any of the materials give off any toxic chemicals to hurt you breathing the air?

[@evronetwork]

what happens during the summer? ..I wonder do they cover them? do they get damaged from excessive heat during the summer?

[@justgivemethetruth]

The flap could prevent loss if it was nonconductive rubber or something ... but it's not a sure seal. The more I look at this the less good it looks. All the hot air would be at the top of the room. What really needs to happen is some kind of heat storage medium and heat exchanger box that the inside of the house can draw on when it needs it.

[@owendeliebs1894]

Wait- is the screen really made out of aluminum or is it a regular fiberglass screen for an "aluminum" door?

[@justgivemethetruth]

I am not sure this is such a great idea, or taking a risk and cutting up the side of your house to install this and then finding out if does not work so well or has major problems at night or in the summer?

[@carlosdemattos816]

what type of screening is used? Why not just add that to windows at home, leaving a gap at the bottom and at top for venting?

[@telluntouhutlapintyttoseik1493]

Is the screen normal black screen?

[@hildebertocarreiro9232]

Sheet metal gets hotter. Try pieces of microfying glass on top 300 degrees .metal might be better in a wavey way inside box.

[@dibrentley7915]

could it work if you did a concrete wall with an air space so the concrete heats up during the day heating up the air and it goes through vents into the house then at night the release of stored heat in the concrete could still be heating the air? Then conversely in summer, the air space gets vented out through a wirley bird on the roof and the vents are closed but the concrete wall is protecting the house wall from heat? (australia with house with a western side wall)

[@Arhtoodeetoo]

thats essentially a trombe wall ur talknig about

[@dibrentley7915]

@@Arhtoodeetoo oh thanks Daniel I will have to look up trombe walls. thanks

[@davidhefner5668]

Why not have both air heat and water heat in the same solar heater.

[@trmwyldshade1482]

I agree. The circulating hot water would act as thermal mass.

[@jackrodgersjr]

Water freezes and at night would become ice if not during the day.

[@henhero]

you put some antifreeze inside ;)

[@trmwyldshade1482]

Ta Da!!! LOL Yes, antifreeze would most certainly do the trick. Although automotive (green) antifreeze is very toxic to animals. You can use the PINK RV antifreeze which is less harmful.

[@Neznisgip]

What do you do with it in the summer?

[@TheJSB007]

Hi, I'm looking at making a solar hot air box and I need your expertise advice, would using onduline bitumen corrugated sheeting be OK to use?

[@havik78]

briljant!!!!!!

[@Aethelbeorn]

perhaps some sort of drape could cover the solar heater to keep it from absorbing the sun.

[@porkytorkwal]

Sinking (falling) is part of the cycle. Why don't you just watch this video again, it has a decent animation of how convection currents work. In your case maybe watch it a couple dozen times.

[@arminemartirosyan4302]

Hi, I have constructed two panels on my own. I have instaled them on the roof. The two panels are connected and drag the air from one room and pump it to another as one. The problems is that on the way from the top (hotest) point of the panel to the fan (approximatety 2.5m) it loses 70°C of heat. I have inserted a thermo snesor inside the panel, so on the top of the panel the temperature is 106-107°C, while the temperature in front of the fan is 30°C. Did you face any kind of similar problems in your panel's work? What may couse that big heat lost in your oppinion?

[@RC-dv7bt]

Armine Martirosyan Air too much faster, i think.

[@yvairguy]

Have you tried the same design with a metal absorber plate side hy side? Any advantage over the screen?

[@milosmatovic5735]

what about summer days??? too hot or not??? How to use the same panel for cooling the areas?

[@roykilgore8461]

How do you shut it off in the summer??

[@erdene-ochirmijid4040]

How do you get fresh air into the house from the outside?

[@mspence0826]

Can this work inside of a greenhouse or does it need to be in direct sunlight?

[@lendoggtheking]

wouldn't it be even more effective with a black backing?

[@1971SuperLead]

Yes, flat black. Glass would work better than poly carbonate, as well.

[@westwindsailer]

1971SuperLead glass is very heavy and expensive, driving up payback costs and making installation heavy and difficult, the plastic works well. Ive seen premade boxes go for over a thousand up here in Canada! wow payback time would take years!! the black mesh screen is a good compromise as its allows air flow through it. Not sure if paint will stick long term to vinyl siding and it could get so hot it may flake or warp the siding and again = cost. I made a solar box using vapour barrier as a film instead of glass or plastic, it was a proof of concept idea it worked great. -25 celcius outside and the box was up to 80 celcius. February full sun in cold Canada. Used a computer cpu fan wired into the box to boost air movement ..it was cheap and worked great.

[@1971SuperLead]

jay herne Around here people throw away window glass. Old single pane sliding doors can be had for free, since everyone is replacing them with dual pane doors. No one is throwing away poly carbonate.

[@westwindsailer]

that's good, and your right it depends whats at you fingertips. Around here old glass goes to the landfill, the good stuff usually goes to whats called "recool" a place that resells stuff for charity...its not cheap.

[@buddysnackit1758]

I wonder if this thing still exists?

[@reeblesnarfle5443]

I am surprised that NO insulation (like Celtec) was installed inside the box to insulate heated air from cold. In addition to the Crltec insulation. I would have layed sheet aluminum on top of Celtec for sheer added heat mass, for collection. If you're going to spend that kind of money, get the max bang for buck. . .

[@kentalex]

Temperature increase up to 80 degrees. But how cold is "Cool air"? How big is the differential?

[@mikegibney2898]

Kent Alexander Johansen. I built a smaller can type unit and on a -12 deg morning in MT was getting avg 95 deg output. we tested in summer on a 95 deg day and saw temps as high as 250-255 deg

[@gardenerinthesand]

Hi Peter. Thank you for your video which I am watching from my farmhouse in France. With its 2 feet thick walls, our farmhouse stays cool during the hottest days, but brr I feel cold even in June! Our current heating system is a boiler wood stove. I would like to supplement it with a solar wall like your video. Just by looking at the internet it looks like our area has about 1900 hours of sunshine/year, with much of that coming to us in July and August of course. Does it matter if the wall is facing a bit SW? What happens in summer when it truly is hot, and do not want to heat my home? Is it possible to get building instructions? Is there a way to calculate how much solar heat could be harvested from a wall? How can I determine if it is "worth it?"Could you kindly point me in the right direction? Thanks!

[@moonxshakti]

There are other solar heater videos with measurements of heat produced, and many that are not necessarily attached to the wall so you can fully face the Sun. There are also many ways of Designing solar heaters as well as many ways of bringing the heat through the wall. I suggest you look at several other solar heater videos.