Complex sentence: JPA Designer is a suite of software, developed by JPA TL Ltd. It contains thermal calculation tools which enable designers to calculate and improve the energy performance of buildings and to demonstrate compliance with the requirements of UK Building Regulations.
Split into simpler sentences: JPA Designer is a suite of tools which calculate the energy performance of buildings. It enables designers the ability to calculate and improve the efficiency of dwellings and to demonstrate compliance with the requirements of UK Building Regulations.