Your air conditioner costs thousands of dollars, burns electricity all summer, and will need replacing in fifteen years. The earth under your feet costs nothing - and it stays cool year-round.
Earth tubes - also known as earth-air heat exchangers or geothermal cooling tubes - are one of the oldest passive cooling technologies on the planet, used in some form since ancient Persia, and one of the least known among modern homeowners and builders. A length of buried PVC pipe, a gravel bed, and a cracked window are all it takes to deliver free air conditioning for the lifetime of your home - passively, silently, and at zero operating cost.
This is the most comprehensive DIY guide to earth-air heat exchanger design and installation ever written for the existing homeowner, new home builder, homesteader, and off-grid community. It covers everything from the physics of geothermal cooling to the hands-on trench work, from ancient Persian qanats to the latest research on backfill materials and corrugated pipe performance.
Inside you will find:
- A complete honest pros and cons assessment - including when earth tubes are NOT the right choice for your site
- Step-by-step installation from trench planning to interior finishing
- The Larry Larson slit-and-sand method - the highest-performing DIY earth-air heat exchanger design documented
- Two original designs: angled tubes for condensate water collection, and spiral tubes for small lots and bermed homes
- How to size your system for humid climates, high water tables, and off-grid communities
- What goes wrong - and how to spot it before it becomes a permanent problem
- Every other low-cost cooling method worth knowing about, and why earth tubes outperform most of them
- Community-scale geothermal cooling for ecovillages and intentional communities, with documented case studies and real performance data
- How earth tubes pair with passive solar design, rocket mass heaters, and thermal mass construction
The book also covers the history you did not learn in school: 3,000-year-old Persian qanats that cooled entire desert cities without electricity, the termite mounds that inspired a net-zero office building in Zimbabwe, and the prairie dog burrow that applies Bernoulli's principle more elegantly than most HVAC engineers.
Whether you are building new, retrofitting an existing home, living off-grid, or designing housing for a community, this guide gives you everything you need to put the earth's stable temperature to work - permanently, passively, and for the cost of a weekend's worth of pipe and a rented trencher.
Cool your house without AC. No electricity required. For life.
