As houses become more insulated and weatherproof, they also become less permeable to air and moisture. This means that both the air inside the house and the moisture generated by the occupants are not easily renewed (air) and eliminated (moisture) as in old drafty houses. There are three main solutions that are generally offered to residents of ‘super-insulated’ houses:
- Manually and diligently air the house by opening and closing windows and doors
- Install venting grids on windows and/or doors (albeit defeats the purpose of installing energy-efficient windows and doors)
- Install a mechanical and automatic venting system or HVAC
Because our house will be rented out and occupied by people who may not be familiar with the functioning of low-energy housing, we opted for installing an automatic venting system.
There are many different venting systems out there and we chose one that is commonly used in passive or even positive housing. It consists of a ventilation unit with heat recovery combined to a ground-to-water heat exchanger (earth tubes with ethyl glycol solution). More information on our system can be found by following the link below
Over the past month and a half, we worked on installing the piping for the ground-to-water heat exchanger. All-in-all, it took us close to 10 days of full work to install 185 meters of tubes at an average of 2 meters below the ground. We had hoped not to find too much rock in the ground but it was wishful thinking. We dug up more than 90 meters of trench of which 35 where almost all rock. In some places we went as deep as 2.6 and in other places we could not go further than 1.2m because of the rock bed.
We installed two loops of 32mm PE-HD (Polyethylene High-Pressure) tubes for a total of 185 meters of hose. We made the trench 0.8m wide in order to lay two tubes in the same trench, 0.6m apart from each other. We used 10 to 15cm of thin black sand, from a near-by quarry, to set the tubes in place and envelop them with consistent and even material before refilling the trench with soil and a ‘few’ rocks.
The pictures below will tell you the rest. Use the “View with Piclens” function to see all pictures and comments.
