This study is to evaluate the heating performance verification of ground source heat pump systems with U-tube and double tube type ground loop heat exchangers. Both the GLHEs were designed by using the GLHEPRO being a very popular commercial program to design various GLHEs. The U-tube and double tube GLHPs were installed in the same building, but each system was in charge of different space air-conditioning. The performance of the double tube system was similar to that for the U-tube system at the beginning of heating operation, while the former was lower than the latter as days went by. Therefore, it is needed to execute the experimental verification for the design results of the double tube GLHE for long term period to prove the reliability of the system. (C) 2012 Elsevier Ltd. All rights reserved.