Low-tech doesn't mean primitive, and it doesn't mean going without technology. It means choosing solutions you can understand, repair, and often build yourself: fewer parts, fewer dependencies, fewer things that can only be fixed by someone else.
That's a trade-off, not a free win. A rocket mass heater asks more of you than a gas boiler. A dry toilet asks a great deal more than a flush. What you get back, however, is worth it:
When you build or maintain something yourself, you know how it works, what it needs, and what it means when it starts making a noise it didn't make before. You stop being a customer of your own house. That knowledge compounds: it changes what you notice, what you can fix on a Sunday afternoon, and what you can judge when someone quotes you for a job.
Most of a system's environmental cost is settled before it is ever switched on: what it is made of, how far it travelled, how long it lasts, and what happens to it at the end. Low-tech solutions tend to do well on all four, especially if they are passive (no power use).
Often much less, especially where your own labour replaces a contractor's. Sometimes the saving is upfront, sometimes it is twenty years of not replacing something. But not always. Some low-tech options cost more to build and pay back slowly, or never, in money alone. In the catalogue we try to give you some insights about relative costs between different solutions.
Grids fail, supply chains stretch, prices move. A system that needs no pump, no mains connection and no proprietary spare part is largely indifferent to all of that. You don't need to believe in collapse to value this. A week without power or two days without water is enough.
This gets left out of serious discussions, which is a shame, because it is often what keeps people going. Building something that works is a good feeling. Understanding how something functions is a good feeling. Watering your garden with yesterday’s shower is, unexpectedly, a good feeling.
Some conventional systems are simply better. A heat pump moves more heat per unit of electricity than anything low-tech can. Mains water is safer than most on-site treatment. Pretending otherwise would waste your time. On the other hand, redundancy is a good idea for anything really important: having a high tech default solution, and a low tech backup that you can use when needed is a pretty good setup.
So this catalogue includes both. Where a conventional system sets the performance ceiling for a need (and where we've been able to map it) it sits alongside the low-tech options, rated on the same axes. So you can see what you'd be giving up, or gaining, either way.
The interesting question is rarely "low-tech or not". It is which parts of your home you want to hand over, and which you want to understand, build, be able to repair and keep in your own hands.