Why do you want to use oil? Why not water? It's more efficient and cheaper to buy. You could possibly use a drain back system on your collectors.
Around here, the building contractors are putting pex into the sand layer under the slab. Under the 1 to 2 ft. layer of sand is board insulation. The zone rotameters and feed lines originate in the garage and must be turned on in August or Sept to have heat in October or November. A 50 gallon hot water heater fuels the whole system.
The same board insulation is also used to create insulation for the concrete.
|