Free heat with minimal investment. Having a serious interest in renewable energy, I recently got the urge to try and create a solar insert that would simply slide into my existing window casings to help with the heating of my 1996 mobile. I saw on the local news one night how a local man built a solar thermo siphon (TAP) air panel to do just that using black aluminum window screen and plywood. OK, that's fine if you don't mind living in a cave as it totally blocked the view and incoming light through the window. The concept is fine and it works. He made a comment about how much he saved on heating, but I don't remember what he said. Having seen many designs on the internet of solar space heaters using black window screen, I decided to test the idea last winter as I had a difficult time believing window screen could possibly generate much heat. So, I grabbed a couple of screens I just happen to have and attached them to the front door with magnets salvaged from a micro wave. Amazing!! I think I was getting over 120 deg. I didn't write it down so I am relying on my (poor) memory.

Anyway, I wasn't too keen on losing the view or light so I set my mind to wandering and came up with the idea of using poly film instead of plywood. The first prototype was made using poly film and the initial test gave me 90 - 94 deg. with the sunlight hitting about 60% of the window screen. Not bad. OK. Now, how can I improve this? If I can reflect the sunlight onto the backside of the screen, it should generate more heat. Aluminum foil? You would need a substrate to attach it to and it would also eliminate the view and light. Then it hit me! Aluminized Mylar (emergency blanket, rescue blanket etc.)!! I recalled that as I was playing with other solar projects that these blankets reflect light and heat yet are also semi transparent, so I tried it. Super! It is like having polarized windows and it boosted the output temperature about 4 deg. This winter will tell the tale.

Now, on with the instructions...

What you need:
3/4" square molding for basic framework
Black window screen - the window screen I see around here isn't really black but Charcoal. Still dark enough to serve as solar absorber.
1/4" X 3/4" molding for attaching film to frame, screen bead molding?
Saw - table saw or miter box
Drill motor
Screwdriver or power driver
wood glue - optional
a sharp utility knife to trim excess film
heavy duty scissors or tin snips for cutting window screen - you might also consider gloves when working with aluminum screen
#6 X 1-1/2" wood screws - I used 8 per frame
#6 X 3/4" wood screws for attaching trim molding
countersinking drill bit for the above screws
Staple gun and staples - 1/4" - 3/8"
POly drop cloth, emergency blanket or other transparent sheet to enclose air chamber and for anti siphon flap valve. Another option that may improve efficiency would be a thin polycarbonate sheet screwed to the frame.

Step 1: Build the frame

Measure your window opening and cut 3/4" square molding accordingly. My windows are 29" X 59" so, two pieces 28-15/16" for top and bottom frame, 2 pieces 57-7/16" for side frames and two pieces 27-716" for inlet/outlet frames. I cut the pieces for the main frame 1/16" short for a slip fit into the window opening. A tight seal isn't really necessary unless you have serious air infiltration around your windows. In that event, I would either properly seal the leaks or make another frame that you can seal tightly against the existing window and cover it with plexiglass/polycarbonate.

assemble the top and bottom rails to the ends of the upright rails using one #6 X 1-1/2" wood screw at each joint. Here is where we might add wood glue for a more durable joint. Make sure your frame is relatively square and fits well into your opening. Not too tight and not too loose. A competent woodworker might dado the frames for a more professional look.

Now, add the inner rails that will create your inlet/outlet openings. Considering my window size and emergency blanket size (52" X 84") if I make the inner opening 50-1/2" high, I can use the 52" width of the blanket with minimal waste. That makes my vent openings 2-3/4" high by the width of the frame. There is a formula for determining the vent size but me and formulas don't get along too well. Some percentage of total collector area.

Now you might paint or stain your frame if desired.
<p>Hey wow, someone that made something similar to my solar air heater approach? How is it working out for you? Here is my setup and construction if you are interested. Nice man, thanks!<br>https://diybarrelstoveoutdoorfurnace.wordpress.com/2014/12/28/diy-window-mount-solar-air-heater-presentation/</p>
<p>Thank you for this nice instructable</p><p>Rima</p>
<p>I don't have the mylar to test with, but I'm relatuvely sure you could use one of thos screen repair kits to make a very taut mylar sheet. usually, you pull the old saggy screen out and place a new one over th old area. There would be a furrow around the perimeter of the frame in which to roll a rubber gasket from the repair kit.<br><br>I think that would avoid the possibilty of ripping mylar from the wood strips.</p>
Great idea! I was just writing my group about our simple frames. Hubby and I made double sided frames from 1&quot;x 2&quot; wood frames and stapled clear vinyl shower curtains over both sides. (bought cheap at $1.00 ea). We put them in all the windows. The one in the bathroom is getting ragged and we just put it in anyway. The upper flap flopped down and when I reached up to tuck it back in I felt warm air rising up out of the thing! When I have time I want to revise these to include the screen on one side and clear vinyl inside with an upper flap to allow hot air to pour out. :)
After reading all the discussion about thebriguy's solar panels and WhoTookMudshark (and others) comments, I had to get my two cents worth in. <br> Is it possible for everyone, including the practicalists and the thermodynamicists to be right? I think it is. <br>First of all, it is obvious that putting up a solar panel is not going to cause any more light (and therefore heat) to come into a room. As was pointed out, that is controlled by the size of the window. As was also pointed out, all that light bouncing around the room is being absorbed by carpet, furniture, your bobblehead collection, etc. <br>The thing is, neither the carpet nor the chair is a very good re-radiator of heat and so the chair feels nice and warm if you sit in it because of CONDUCTION and the carpet feels warm (if you have your shoes off) because of CONDUCTION, not radiation. <br>In another vein, folks usually keep their windows covered with drapes in cold weather to reduce heat loss through CONDUCTION, unless they have double or triple pane windows in which case they might not need a solar panel in the first place. The other reason for closing the drapes is so that UV rays don't discolor or rot the chair fabric (or fade the bobbleheads). <br>Thermodynamics aside, thebriguy did the one thing the body can relate to. He heated the air. Therefore, with the solar panel installed, while the furnishings <br>might not be warm, the air is, and that makes people in the room feel warmer as well. And, not to be taken lightly, the solar panel probably keeps some room heat from being conducted outdoors through the glass. <br>I think we could all be happier if we agreed that thebriguy's panel does not make the absolute room temperature any hotter, but it does convert the available heat energy into a form that the human body likes best. AHHHH, pass sthe hot chocolate.
Hi, Bit off topic but can I&nbsp;buy my own land with 10-20 bushes&nbsp; and place a motor home on it?<br /> IS there any laws against it? zonning etc. Since bushes will hide it from plain view from a far?<br /> or I&nbsp;can only have one in a trailer park like I hear mostly?<br /> thanks a lot.<br /> Al Boz<br /> <br /> <br />
You need to check your local zoning laws and you may need to have utilities supplied to the property before you can place a mobil or manufactured home on it. <br> <br>Budd
You should monitor you fresh air intake to make sure that you are getting enough 'fresh air' as not to fall victim to carbon monoxide poisoning.<br>I live i a mobile home as well, and these are not built as &quot;houses&quot;. The gas pipes are right under your floor, and although the homes are built to have 'give', gas pipes aren't.... So you may have small gas leaks and not even be aware. <br>Just be careful.<br>Fantastic idea, though!
This looks like a nice project and relatively easy to undertake. I wonder how it worked during 2009-2010 Winter and what your outside temperatures were. <br> <br>Good work, sir !
I hate to be the bearer of bad news, but if you use an existing window it is physically impossible to have any impact on the heating. The sun coming in that window was already being absorbed by everything in your house and converted into heat energy. :)
Yes and no... while you are correct in a larger sense (and I would never recommend someone try to heat their house with one of these 'solar heaters')... depending on the energy efficiency of the windows, they allow light (and heat) to escape out of the house. If you set up a solar over inside the window, and circulate the air through it, you get a much higher efficiency of light to heat conversion, and more importantly, <em>retention</em>.<br/><br/>Thus you could save pennies per month in your energy bills by retaining a bit more solar heat - and you would also feel the noticeable stream of warm air which would convince many people it is functioning much better than it actually is.<br/><br/>Of course, the solar inserts in this Instructable would have next to no impact on said retention; in fact it will likely lessen the retention and reflect out more heat than you had before, as it has no proper chamber to heat the air or circulation of said heated air.<br/><br/>You probably know this already and are simplifying to get your point across; but if you explain where the myth/misinformation is rooted, people are much more likely to both believe, and more importantly, understand.<br/>
Thank you for your polite explanation. The value is more in comfort than a heating bill - for my children's room - It will warm a room (I should have not deleted my previous posting). The best designs of these utilize the exterior of the home without obstructing the window.
Yes, a panel mounted outside on a wall would be more effective, in fact I have a panel mounted outside as well, but then you are cutting holes through the walls which is somewhat discomforting to me. I have had over 200 degrees coming from that panel and I need to re-vamp it a little to increase the air flow and bring that temperature down. Then, there is Mother Earth News "Heat Grabber". I had considered trying one of those, but it is rather bulky and you would need a large storage area when it is not in use. I will monitor my inserts this winter and post the results here. I have five windows to fit these to, 3 on south side and 2 on east side.
speaking of mother earth news heat grabber,i built one simular with material i had on hand i was very pleased with the output.I recorded temps as high as 190 coming out in a steady flow on icy cold days with snow covered ground,the more heat it put into my home the less my electric heaters kicked on. i was so pleased i showed my brother the results and he now has one on his home as well
as for storing it in the summer i simply built an add on box at the top to turn it into a solar dehydrater, great for jerky <br>just as a side note sitting in yard not attached to anything ,snow and ice on the ground ,i recorded tempt with a digital temp. at 70 degrees it was 22 degrees outside at the time
<em>Of course, the solar inserts in this Instructable would have next to no impact on said retention; in fact it will likely lessen the retention and reflect out more heat than you had before, as it has no proper chamber to heat the air or circulation of said heated air.</em><br/><br/>In essence there are two air chambers in these inserts one between the window and the insert, and another between the screen and mylar film. The cooler air enters at the bottom and weaves through the screen on its way up and out the top vent. I don't have a suitable graphics program to create a diagram of the process, but if you check out the &quot;Solar Barn&quot; at Home Power.com, there is a good explanation of the thermo siphon process.<br/>
if that were true, nobody would be able to see into your house because of 0 reflected light(if it were all converted to heat)
You're splitting hairs! Of course some light makes its way out, but not anymore than the light that leaks out after this project is completed. I was generalizing to avoid being too wordy. :)
maybe even worse: the mylar material is actually reflective, so more of the light will be reflected out of the house before it can even warm the interior?
Yeah, that's a common statement in the solar circle and I understand the thoughts behind it, but I'm a prove it to myself kind of guy and will see what happens this winter.
<br> Some of the people here ARE correct in that any sunlight coming through the window heats the building, no matter how much magical stuff there is around the place....<br> <br> <br> BUT the screen thing ALSO acts as a form of double glazing.... thus lowing the heat loss to the outside environment.<br> <br> Sure one can get all nit picky and toss the sausage or spank the pony about it, but you know.... the ultimate guide to being a pedant - but it's the double glazing that when sealed at the base after the sun no longer shines - that is what bias's the thermal cycle towards the interior.<br> <br> The &quot;true average&quot; of incident sunlight is stated as being about 1000W a meter squared; if only for a universal bench mark.<br> <br> AND if the sunlight IS landing on it, and then when the sun is not landing on it, the interlayer venting process is stopped or the convective cooling is stopped, then the net gain to the interior can be significant.<br>
That's pretty cool. I didn't notice, have you had a cold winter to try this out yet? I would suggest making the upper inner rail a bit taller(or the trim a bit shorter) leaving a little more room for the upper control vent to seal across the frame's width without needing to be as precisely placed.
Actually, it is late Oct. and winter is just starting, but I do have some performance input. <br /> Since I have such a snug fit in the window frame, I decided to cover the insert's exterior facing frame with the clear heat shrink window covering kit. I believe it increased the efficiency considerably, as it is heating just the existing room air and not the cold window air. Just the other morning, at 10:00 am, the outside temp. was in the low 40's and I was getting 96 deg. out of the window insert, while getting 84 deg. from the external solar panel. I have noted 110 deg. from the insert from earlier observations. At that time, the external panel was contributing 180 deg. to my bedroom and the room temp reached 75 deg. (heaven). I have a really low tolerance for cold temps.
What is the REAL amount of energy you can take out of such a panel?<br />I read in a review on some DIY solar panel guides that they use&nbsp; awesome examples but that in fact this is nonsense.<br />Here is where the reviews are: <a href="http://energy.e-bookz.info">http://energy.e-bookz.info</a><br />Anyone an opinion?<br /><br />
Just to add a 2cent advice.<br />As some said, there are two different things :<br /><br />the amount of &quot;heat&quot; (energy)<br />the temperature of the different elements of the room (air, walls, floor)<br /><br />For those who are not trained in thermodynamics, it is easy to understand the difference.<br /><br />Compare energy-heat with a VOLUME of liquid in a bucket (say 3 litres)<br />and compare temperature with the LEVEL&nbsp;OF&nbsp;WATER&nbsp;in this bucket (say 6 cm).<br /><br />If you take another bucket (smaller in diameter) and put your 3&nbsp;litres in it, the height of liquid (temperature) will be higher.<br /><br />This is why it takes longer to heat metal (large diameter bucket) than plastic. It will take more heat to reach the same temperature.<br /><br />In the case of this instructables, people are talking about 10&deg; increase in room temperature. This is in fact air temperature. If they check the walls, they may find a much lower temperature. Air temperature is the real measure of &quot;how good we feel&quot;, but it is a wrong measure of &quot;how warm is the full room with walls and floors&quot;.<br /><br />I think what is happening is when you don't have the screen, you heat walls and floor. The concrete needs a lot of heat to warm up, so the light coming directly from the window does not heat air and doeas not increase much the concrete temperature.<br /><br />With the screen the heat entering the room is first CONCENTRATED in the air. It is logical that a (air) temperature increase be registered and that occupants feel better.<br /><br />Of course, the air will then heat walls and ceiling (remember, hot air goes up), so the net effect is physically zero. But as the nervous system of occupants is concerned, they will feel better, as long as they don't touch walls and floor.<br /><br /><br />
Well, I'd like to send you some of this Florida Heat !
its a net positive effect because less light is bouncing off non-black items in the room and back out of the window WITHOUT being converted to heat. I think this is what WhoTookMudshark was missing. To reiterate, the more light that hits a dark surface and is turned to heat, the less that gets reflected back out the window in the form of light and uncaptured heat.
but I would leave out the mylar as well, you don't want to relect, just absorb.
Cool idea, maybe you could hang something out the window as to not block sunlight.
Nice! I was expecting it to be transparent.. but still pretty darn cool- I mean HOT!
Actually, it is semi-transparent. if you lok at the opening photo, you might notice the railing for my fathers handycap ramp outside the window, and a few trees. That was one of my concerns when I came up with this.
Try colored water. Absorption rates are different.
That is pretty cool.or is it hot? = ) for more solar projects check out www.motherearthnews.com <br/>
hmm pretty cool

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