1 Time from start of nest building to departure of young is 44 to 58 days. 2  Nest building is done by both sexes and begins around April. Both parents take turns incubating three to five eggs, which hatch after 12 to 17 days.  Brood parasitism is common among cliff swallows.
Geothermal heat pumps, which pull heat from the ground making them more reliable and efficient, usually cost somewhere between $9,000 and $23,000, including installation. The price for either style of heat pump is dependent on: The heat pump brand.
According to the United States Department of Energy the average cost of a geothermal heat pump system is $2,500 per ton. The agency goes on to say that the average residential property is going to require a unit of three tons to supply their needs. This translates to a $7,500 cost for the system.