solar collector or solar reflector--legal and low-profile, for in the suburbs

I'm sure there's already posts about this but I haven't managed to find the relevant ones after looking through 50 search results, so feel free to point me to the right thread.



I have alarmingly small windows on the south side, and the heater is oil.  We are renters.  It's suburban.

The designs for bringing convective heat ("solar collector") into a window involve leaving a window partway open all the time, plus convective.  But at least it can hang down flush with the wall.

My super-bad experimental solar reflector pizza box fell apart in the wind after a few weeks, and never really managed to reflect that much.  And if it were large enough to really reflect sunlight into the windows, it would have to be larger, stick out really far, and probably be against some suburb rule.  I think a neighbor would see it and have concerns about it falling on someone's head.  Whcih would, arguably, most likely be mine, but still I've often seen people copmlain about perceived dangers of falling objects.  They never, ever go in their yard except to mow in the warm season or powerwash their walls, so the danger is not real in my opinion, but perceived.

My hoverpond didn't work because there's no such thing as a hoverpond.  (That we know.). It was going to be a nice big pond on the south side that never freezes and hovers about 16 feet above ground and somehow magically doesn't drown the nieghbor's house...or does it? :p ). It also has hoverfish, a hover aerator, and hover sushi chefs.

So, I'm thinking the solar collector is the only viable choice. And I wish there were an off-the-shelf thing that could be purchased but it is...$1000.  For a really small one that could at most capture...3000watts under laboratory conditions.  That's not much. 32"x64" is about 2.5'x5', is my math right?  = 10 square feet, about 3 square meters, 3kw?  Someone's making good money.  And it runs on a 12v fan.  Has no one heard of thermosiphoning??

Collector:
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pro's:
can lie flat along the wall, discreet
less likely to break
less likely to blow aprt in wind
less likely to fall on someone's head
can make cheaply from cardboard and plastic bags

cons:
convective heat only
window must stay open where it enters
no off-the-shelf option
drafty, will dry the plants somewhat (even hot air coming in, if it even is hot, is still drafty and will dry the plants somewhat)





reflector:
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pro's:
radiant heat
window can stay closed, radiation passes through
helps the plants more, light as well as heat
less drafty (even hot air coming in, if it even is hot, is still drafty and will dry the plants somewhat)

cons:
must stick out laterally to function, nearly horizontal
if glass, dangerous, f reflective plastic, flimsy
reflective plastic is more expensive than just clear or black plastic garbage bags
reflects the sun into the window only for about an hour a day, unless we put a whole row of them all along and some far out from the house between the windows
if curved, it could get dangerously hot

I'm not satisfied with either of these.

Any thoughts?  Thanks geniuses.

BTW the longer term plan is just to move and build an annualized thermal intertia-aided house

Okay, here's the heat grabber on builditsolar

And yes, it does require an "open" window, but it's the same deal as with a window A/C unit, except maybe a better fit/sealing than those accordion baffles give. There's also the opportunity to use that shrink film plastic to seal the inside to stop drafts (as well as using the foam fillers where the sashes overlap.)
For a renter, this is possibly a good option, since no modifications are made to the structure, and you CAN take it with you. (assuming using in a new place or whatever.)

If there are storm windows, a variant of this would be to modify the storm window to incorporate the "grabber" and cut the draftiness considerably.

Another idea could use the same ducting through the window, and replace shutters on the house with collectors hung there instead. A little bit intrusive (store the old shutters in attic/basement for replacing later), but a little more "stealth" and more secure than the "grabber" hanging off the windowsill. Heck, in the case of no shutters, this would just look like you added shutters... you could go above and below the window as well for more area (though losing the 'stealth' of shutter mimicry).

If there are adjacent rooms with similar windows, a larger wall collector could go between them, maybe even flowing from one room to the other.

Another "stealth" option would be to make it an awning over the window(s) with the side benefit of shading in the summer. (this is a more intrusive/installed option, maybe more suited to hiding from a HOA than for a renter)

Kenneth Elwell wrote:Okay, here's the heat grabber on builditsolar

Thank you for posting the link to the "Build It Solar" site. What a wonderful resource for all things DIY solar! I am looking forward to delving deeper into the information provided on there.

Annie Collins wrote:

Kenneth Elwell wrote:Okay, here's the heat grabber on builditsolar

Thank you for posting the link to the "Build It Solar" site. What a wonderful resource for all things DIY solar! I am looking forward to delving deeper into the information provided on there.

My gosh, yes!! I spent quite a bit of time poring over builditsolar.com learning about and dreaming of projects to build, long before I found Permies. It is a great resource, thanks to Gary Reysa for his commitment to it over many years!