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.
Heat pumps can cost up to $5,000, while the majority of gas and electric resistance heaters are available for around $1,000 and $2,000 respectively. The cost for installing heat pumps and gas heaters averages about $300 to $500, including labor and materials.