A few feet down, the ground stays a steady temperature all year. Earth tubes — also called a ground-to-air heat transfer (GAHT) system — are buried pipe that draw fresh air through that stable ground, pre-heating it in winter and pre-cooling it in summer before it ever reaches your home or HVAC.
Size your home, drop it on your lot and mark where your HVAC intake is. Pick a run strategy — a long out-and-back loop through the yard, or around the foundation combined with a new perimeter drain tile — and we size the run and estimate performance & cost.
Drag the house to reposition it · click a house edge to place the HVAC intake.
A quiet fan draws fresh, tempered air into the home at the whole-house ventilation rate (ASHRAE 62.2).
Air is pulled through pipe buried below the frost line, where the earth holds a near-constant temperature year-round. By the time that air reaches your home it has already given up its summer heat — or picked up winter warmth — for free.
Bitter outdoor air is pre-heated by the ground on its way in, so your furnace or heat pump starts from a much milder temperature.
Hot summer air is pre-cooled underground, taking load — and cost — off your air conditioning, sometimes replacing it outright.
The ground does the tempering. All it takes is a small fan to move the air — a fraction of what heating or cooling that same air would cost.
Earth tubes can pre-condition the fresh air for any home, on their own. But paired with a Sophab — run under a patio, or feeding a GreenPhab greenhouse or a Solarship — they close the loop on a fully solar-passive, low-energy system.
We size the run, depth and layout to your soil, your lot and the air volume your home needs — then hand you a plan you can build to.
