Lowtech Graph lists low-tech options for every need of a home. Here you can compare them, find tutorials to build them, and link them together into a circular system. Why low-tech?
Heat pump (air- or ground-source)
Needs the grid
One of 5 ways to meet this need. Cost, carbon, footprint and rankings are relative to other solutions for the same need, not absolute.
An electric machine that heats the house by taking warmth from the outside air or the ground and pumping it indoors. Because it moves heat rather than making it, it gives several units of heat for each unit of electricity. It is efficient, but it depends on power and a specialist to repair it.
Build it
This solution is not buildable as a DIY project.
Cost
High
Upkeep
Seasonal
Skill to build
Specialist
Lifespan
10-15 years typical, up to 20 for well-maintained units; ground-source loops themselves can last 30+ years even as the heat-pump unit is replaced
Levels are relative to the other options for this need, not absolute. Fewer dots is lighter.
Heat pump (air- or ground-source) (This page) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: High · Skill to build: Specialist · Upkeep: Heavy · Change to daily life: None · Works without the grid: No Choose it if you have reliable electricity and want efficient heat with no fuel to handle.
Wood stove / mass heater Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Basic · Upkeep: Heavy · Change to daily life: Daily · Works without the grid: Yes Choose it if you want a familiar wood fire that heats the house without electricity, from local wood.
Rocket mass heater Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Low · Skill to build: Intermediate · Upkeep: Heavy · Change to daily life: Daily · Works without the grid: Yes Choose it if you want the most heat from the least wood, stored in a bench for hours.
Gas boiler (condensing) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Specialist · Upkeep: Light · Change to daily life: None · Works without the grid: No Choose it if you are on the gas mains and want steady heat on demand from a system every installer knows.
Gravity-fed pellet stove (no electricity) Can I use it? Works in a flat · No rebuilding needed What does it cost me? Upfront cost: Medium · Skill to build: Intermediate · Upkeep: Heavy · Change to daily life: Daily · Works without the grid: Yes Choose it if you want steady pellet heat that keeps going in a power cut.
Sources
Heat pump lifespan industry sources (permies.com heater-lifespan wiki; general HVAC industry consensus)
Limitations of this page
We don’t list sizing or quantities, as the yield of each technique depends on the quality of its build. The catalogue compares options but doesn’t dimension them. Regulatory notes are indicative, with a French example, and need to be confirmed locally.