To plan a DIY project to improve home energy efficiency for sustainable couples, begin by conducting a thorough assessment of your home's current energy usage and identifying areas where improvements can be made. Research different energy-efficient upgrades such as installing programmable thermostats, sealing drafts, or adding insulation. Create a budget and timeline for the project, taking into account the cost of materials and any necessary permits. Make a list of tasks that need to be completed and assign responsibilities to each partner. Prioritize tasks based on their impact on energy savings and start with smaller, easier projects before tackling larger ones. Regularly communicate with your partner to ensure you are both on the same page and working towards your shared goal of creating a more sustainable home. By following these steps, you can successfully plan and execute a DIY project to improve home energy efficiency for sustainable couples.