compared as follows (Less & Walker, 2015): It is important to note that, for example, an overtime retrofit project could be able to stipulate the occupants' need over the time but could perform sub-optimal technically. It could also prove to be costlier. There's a lack of tools to execute over-time projects efficiently. Strategies to increase success Detailed planning must be inculcated from the very beginning. It is recommended to include post-occupancy evaluation at each stage of implementation to deal with modifications required in future stages. Home performance should be tracked at each stage either using utility bills or feedback devices. This helps in achieving the set-target for energy consumption. It must be kept in mind to implement building envelope and passive design elements before making major HVAC and technology investments. This will help to reduce the load parameters for HVAC design. The technology investments should also come later to have an innovation advantage. Over-time retrofits, thus can be guided by these strategies to overcome the challenges and achieve success. Design and Construction Process Deep energy retrofit project has different phases governing them – pre-panning, project planning, construction, test out. The beacon for the design and construction process in deep energy retrofit projects is a set of defined project needs, opportunities, goals and objectives. This completely determines the overall project. Walker et al. provide design and construction process guidance which can be followed flexibly in deep energy retrofit projects in residential homes. Energy efficiency measures Cluett and Amann (2014) found the most commonly implemented efficiency measures in the US for residential buildings. They are broadly listed as follows: Building shell improvements Insulation improvements, usually to the foundation walls/slabs, above grade walls, floors, roof, and attic surfaces that make up the thermal envelope Attention to air sealing, particularly in areas that are harder to address without being paired with improvements to the insulation shell Upgrades to heating, cooling, and hot water systems Upgrade to non-atmospheric vented combustion units that either vent directly outside or are electric only Upgrade to units that are correctly sized for the heating and cooling load demands of an altered building Improvement to or replacement of the existing distribution systems for heating, cooling, and/or hot water, including changes to ductwork, water piping, and wastewater heat recovery The deep energy retrofit specifications for various elements vary from climate to climate zones. Process A Level III energy audit, as defined