Aquatherm Heat Pumps are a super efficient way to heat your pool or spa. The Aquatherm Heat Pump utilizes proven refrigerant technology to capture the heat in the outside air and transfer it to the pool water. Refrigerant is used because of its ability to absorb and transfer heat energy. The fan circulates air through the outer Evaporator Air Coil that acts as a heat collector. The liquid refrigerant in the air coil absorbs the available heat in the air transforming it to a gas. The refrigerant gas is then pumped by the Compressor. When this warmed gas is compressed, it intensifies or concentrates the heat (like a magnifying glass in the sun). This intensely hot gas is then pumped into the Heat Exchanger Condenser where the actual heat exchange takes place. As the pool water passes through the Heat Exchanger, the hot gas gives up its heat to the cooler pool water. The refrigerant returns to a liquid state and is pumped through the Expansion Valve and then into the Evaporator Air Coil to start the process over again. Aquatherm AT 400 Aquatherm AT 600 Aquatherm AT 800 No Shipping Charge in the USA (lower 48 states)!!!!! Please allow 5-7 days for shipping on small items. Please allow 5-14 days on large items such as filters, heaters, and diving boards. All filters, heaters, and diving boards are shipped ground freight. Check your order when received. Any claim of damage must be placed with the shipping company upon receipt. Privacy is not a issue no mailings and selling of any customer information on this site will be allowed or practiced. Also please visit our main web site WWW.AQUALINEPOOLS.COM or check us out atThe Better Business Bureau Online and our "NEW" on-line store www.Backyard-Warehouse.com All Images-Logos-Text are © Copyright - Aqualine Pools 1999-2006