I have maximized the window space for growing plants including for food, medicine, and cannabis in every dwelling I've lived in. I cobble together shelving and strategically position plants on the floor to use the sunlight coming in so I am surrounded by living green all year. I also do a lot of seasonal outdoor gardening, and that is the best I can do since I don't have 84 grand laying around to build a fancy greenhouse.

If someone is building a greenhouse style home, they have to consider the cloud cover where they live, the same as with solar power. It's really cloudy where I live, so this seems like it would actually cost more to heat than a standard house, even one just built out of concrete siding, foam insulation, and sheetrock.

In any case, the amount of heat energy required to produce glass, especially fancy glass, is really, really substantial. You might want to investigate how frickin' huge the carbon footprint is for constructing one of these buildings is before you start attributing some kind of environmental benefit from it.