This began life as a much broader question on the site but I'm attempting to parcel it out as smaller topics to make it more digestible:
I am trying to find ways, as the title suggests, to combine modern low-tech ideas with the life of medieval serfs, peasants, commoners, etc. Specifically, modern innovations that would help improve their homes that can be replicated in their time/state without the need of most modern technology (computers, cell-phones, electricity, automobiles, etc.). The idea is to for them to give them ways to "work smarter" instead of necessarily "harder."
The examples I've been using are: imagine a group of modern people leaving society to start their own technologically-free one on a virgin world exactly like Earth, swearing off any modern methods that can't be reproduced without technology. Or, if it works better, imagine time-travelers going back into time to the Middle Ages and giving medieval serfs modern techniques, tools, and ideas they could use and replicate in their own time. Or, if you like, how foreign aid is helping to improve third-world countries improve their quality of life with these low-tech innovations. If any of those help, use them (I will divulge more if I need to).
I've been looking into a lot of different areas for this, but I am looking to see how a commoner's home - their house and the acre or so that home occupies - could be improved with these kinds of modern (but low tech) innovations. I've looked into areas like the modern homesteading movement, green and eco-friendly living, foreign aid efforts, survivalist and apocalypse training, etc.; and into specific innovations like rocket stoves, powerless refrigeration, rainwater capture, air wells, low-tech greenhouses, permaculture, etc. There are plenty of things...
Personally, I see a lot of villages being made of self-sustained acres of gardens and stables, on the same acre(s) the houses occupy. These gardens are filled with plants that grow well next to each other given whatever climate the village is in, and give the villagers both something to feed their families and sell for personal profit (if not going straight to the local lord). The houses themselves are made of something like cob or rammed earth, with some form of insulation (straw, or some extra layer of available material), with windows that have some sort of sealing to keep out the cold. They have cisterns to catch rainwater, and/or an alternative like an air well to catch condensation. They have primitive means of filtering water, if they need it, using charcoal and layers of sand, etc. They have something like a potted refrigerator, or maybe a below-ground cellar that offers powerless food storage for months at a time. They have something akin to composting toilets so that they aren't simply dumping their waste into the streets or nearby bodies of water, using it instead as fertilizer, etc. Meat is more readily available, in the form of animals and some larger livestock-types, which they can keep in stables that are themselves insulated from the elements and don't need to be brought into the house just to make it through the winter. I could go on and on...
...having said that, that's an ideal, pie-in-the-sky scenario I'm not married to. If it doesn't work, it doesn't work. That's why I'm waiting on the discussion. If that gives you a better idea of what I'm aiming for, though, so be it.
EDIT BY BSIDESWIPED: Given that the question is still kind of broad historically (an oversight I always manage to forget, since it's a topic I'm not especially learned in yet), let me try to refine the question further.
I would say, if I had to choose, at the most I'd like to keep things somewhere between the post-medieval era and the Elizabethan era (if I've got my eras right). Much further than that and it starts muddling my narrative. I hope that helps.