Envirohaven has just installed the tubes for an Earth-Air Heat Exchange system (EAHE) that will serve our Reno model home. This is a simple, cost effective and efficient system consisting of underground tubes that draw fresh air from outside, tempering it to the earth’s constant subterranean temperature (55-60 degrees Fahrenheit) as it passes into the home. Because the Haven is an airtight structure, we have designed an EAHE system to serve a twofold purpose:
(1) to bring fresh air, filtered and tempered, into the home in a completely controlled manner without having to open a window and exposing the home to the extreme temperatures outside, and (2) to create a base temperature that can supplement heating and cooling systems in the home.
Specific to our design are two 10” pipes running underground drawing air from outside the Haven. One Earth Tube (as they are commonly referred to in Europe) will draw air from the North East side of the house, force it underground to cool it, filter it as moves into the Haven’s central core, and then pump it into the Haven to create a fresh, cool inside environment during the hot summer months. The other Earth Tube will draw warm air from the Haven’s adjacent greenhouse, filter and dehumidify it, and pump it into
the Haven to create a naturally warmer environment. Depending on the temperature of the air brought in through the two Earth Tubes the other heating and cooling systems may not need to be used at all for significant lengths of time. When they do have to be used, a lot less energy will be required to create a comfortable temperature inside the home.
EAHE systems are very common throughout Europe and Asia for their low cost, simplicity, and ability to greatly reduce energy use. By narrowing the gap between outdoor temperatures and comfortable indoor temperatures, EAHE systems can significantly reduce energy costs, up to 80% if used in conjunction with a well insulated house, thus greatly reducing energy bills or strain on solar panels. We hope to lead by example, showing that EAHE systems can be a smart and cost effective building practice here in the United States.
Earth tubes are only one element in the Haven’s heating and cooling systems. As we get further into the building process we will post more on the complete heating and cooling system. If you have any personal experiences with EAHE systems we would love to hear from you!