A Box of Empty Soda Cans on a Sunny Wall Warms a Room on Sunlight Alone — Until the Sun Goes Down

My name is Wade Corbin. My house is the last one on the line, so I have had to work most of this out myself. There is a box on the south wall of my workshop. It is black, about the size of a door, and full of empty soda cans. On a clear January morning, warm air comes out of the top of it and into the room. Nothing in it burns. In the simplest version, nothing in it plugs in. You have probably seen a video of one of these where somebody holds a thermometer to the vent and tells you it heats their whole house for free. It does not. But it does something real, and the Department of Energy describes exactly what. In this video: What it actually is — a solar air heater, in the Department of Energy's own words; the cans are just a way of making a black metal surface How the air moves — the fan kind and the passive kind: cool air in at the bottom, warm air out at the top The two things that decide it — the wall must face within 30 degrees of true south, with no shade from 9 a.m. to 3 p.m. in winter, when the sun is low and the shadows are long What it honestly does — the one university test (77 degrees in, 105 out, on a sunny June day, with a fan) and why the Department of Energy calls the small ones "a small amount of heat" Where it actually pays — one or two rooms, against electricity, propane and oil The catch at sundown — without a flap it runs backwards and pulls the warm air out of your room all night Why it never replaces your furnace, and why it is not free (DOE: a few hundred dollars) The safety part — nothing that makes heat inside it, and air back into the same room so nothing can backdraft a stove or furnace The free version — the south curtains: open by day, closed at night Go and check which way your sunniest wall faces this week. Then tell me in the comments: south, west or east. I read every one of them. Subscribe so you do not miss the next one. Stay warm. Stay dry. And remember, the people who had to work these things out for themselves usually got closer to the truth than the people selling you the answer. #SolarHeater #SodaCanHeater #NoElectricity #WinterPrep #HeatingCosts #RuralLiving #SelfReliance #DIY #OffGrid #ThingsThatWork