Earth to Air Thermal Exchanger (EATEX)

Earth to air thermal exchangers, also known as earth tubes, can provide a passive means of preheating and precooling ventilation and process air by exchanging thermal energy to and from the surrounding earth. This reduces the reliance on electricity and fossil fuels in managing a building’s indoor climate conditions.

Despite their energy-saving benefits, earth to air thermal exchangers have not been widely adopted in net-zero energy buildings. The main reasons for this, as cited in the EATEX Design Principles Guide, are performance uncertainty and a general lack of understanding of the technology.

The following design principles, result-oriented case studies, and early design tool were created to ease uncertainty towards earth to air thermal exchangers in building design projects.

Download the tool

The EATEX Concept Design Tool allows building designers to assess the energy performance of various design options for a series of Canadian climates.

• Download the EATEX Concept Design Tool (.xls) and the corresponding license agreements (.zip, 141 MB)

Download supplementary documents

The EATEX Design Principles Guide (PDF, 1.35 MB) explores factors that affect system performance and cost, provides design principles, and applies the principles using energy simulation tools.

The EATEX case studies supplement the guide and design tool by providing background and results on six EATEX systems in Canada. Download:

• Case studies 1 through 6 (.zip, 10 MB)
• Case study 1: Agricultural processing building, Kelowna, British Columbia (PDF, 4 MB)
• Case study 2: Residential single-family home, Kelowna, British Columbia (North side system) (PDF, 2 MB)
• Case study 3: Residential single-family home, Kelowna, British Columbia (South side system) (PDF, 2 MB)
• Case study 4: Commercial office, Salmon Arm, British Columbia (PDF, 2 MB)
• Case study 5: Commercial office, Kelowna, British Columbia (PDF, 2 MB)
• Case study 6: Earth Rangers Centre for Sustainable Technology (PDF, 2 MB)