Swing Pressure House

I have an impractical idea that may have beneficial effects for our space program: A house in which there is no carbon dioxide whatsoever, and it's all shunted aside to a greenhouse. This both benefits the plants, and is a security system for pests and vegetable thieves. We start with an oxygen generator, a machine who's name is a bit of a misnomer. It doesn't chemically generate oxygen so much as concentrate oxygen in the air. We want the industrial type, because it's cheaper, has higher airflow, and makes fewer assumptions about the air flow stream. This is used to pressurize an airtight house to 1.1 atmospheres. The higher pressure is to ensure that if any leaks do develop, the air flows out, not in.
Next, for dealing with the exhaled breath of the house's occupants, we have an airflow system that takes air from the house, and bubbles it through a hydroxide. All metal hydroxides react with carbon dioxide to form carbonates, which filters the carbon out of the air. Calcium hydroxide would be my primary choice, as this produces heat when synthesized, and is easily cleaned due to calcium carbonate being insoluble in water. You could even check visually to see when a hydroxide sample is worn down and needs replacement. Unfortunately, the synthesis of calcium hydroxide is more complex than sodium hydroxide, which can be produced by electrolyzing salt water. Enormous vats of hydroxides keep the air carbon free.
Over at the greenhouse, the metal carbonates produced by the air filtration system are bought to a lime kiln or vat of strong acid. The carbon becomes liberated from the metal, and spews forth throughout the greenhouse. This suits the plants fine, as the original earth's atmosphere was something like 30% carbon dioxide. As far as plants are concerned, modern earth is polluted all to hell with oxygen, which they produce as waste.
I wanted to make this a closed cyclical system, in which the greenhouse reset the conditions of the house, and vice versa. This would be necessary in space, where the gathering of additional materials is not possible. In space, if you did not bring with you, then you do not have it. I would recommend a calcium based system for this:
CaCO₃ + HCl → CaCl₂ + CO₂ + H₂O
H₂O + electricity → H₂ + O₂
CaCl₂ → Ca + Cl₂ H₂ + Cl₂ → HCl
Ca + O₂ → CaO
CaO + H₂ → Ca(OH)₂
Ca(OH)₂ + CO₂ → CaCO₃
On earth, a sodium based system is probably more practical: NaCl + H₂O → NaOH + Cl
NaOH + CO₂ → NaCO₃ + H₂O
CH3COOH + NaCO₃ → CH₃CO₂Na

You now have an endless supply of hand warmer and poison gas.

Windshield Wire

There's a small icon on my car's dashboard.

When I push this button, current runs through tiny wires in my car's back window, and the resistance to this heats the window up. The head makes water deposited on this window by condensation evaporate, making the window clear for me to see out of. This is legally mandated for my car, as lawmakers think it a reasonable expectation that I be able to see what the hell is going on behind me when I drive.

The windshield, though, or front window, is defogged by blowing hot air from the engine. This is partially because the engine is right below it, and this is a ready source of heat, but mostly because the little wires would be way too prominent at that close a distance. The back window is six feet away from me, the driver. The little black lines are just too tiny to notice at that distance. The windshield, though, is merely inches away. To put little wires here would mean looking a little black lines constantly while I drive.

Let us suppose, though, that I didn't mind the wires, but needed some sort of automated system, so I don't have to bother with the button. I think I would resolve this by materials science.

I would need to produce a material that conducted electricity, but developed greater resistance under low temperatures. In temperate environments, where the window does not fog up, the wires conduct efficiently, and very little heat is produced. However, in colder environments where my own body heat makes a temperature gradient that encourages condensation, the resistance rises considerably, producing heat, and evaporating this fog before it can really get started.

Nah, there's defoggers set up the way they are for a reason.

However, if I were redesigning cars, I would make each of its vents independent. The front vents for blowing air at my face, the lower vents that blow air at my feet, and the vents that blow air at the outer windshield would each have their own dial for temperature and amount of air. As I turn the amount of air dials up, a fan in the vent is given more voltage, making it rotate faster and push more air. As I turn the temperature dial up, more of the air is routed past the radiator.