Before I answer your very specific question, I would like to know what your intention is in choosing to live entirely off the grid. Does your concept include your water supply and sewer, or do you rely on municipal services? Why do you plan to regulate the temperature of your space with a wood stove and an A/C wall unit instead of using a hydro-solar system for heating and cooling? With the exception of very remote locations, going off the grid is in most cases not the most ecological nor economical choice.
If your goal is to build the most environmentally friendly and healthy residence within your means, I would recommend you consult with a licensed architect who is also a LEED AP (Leadership in Energy and Environmental Design Accredited Professional) to develop the most efficient and adequate design that incorporates your needs. Your architect will show you how to avoid expensive mistakes, how to obtain permits and how to get federal tax rebates and solar subsidies which vary by state. Bob Vila gives a good description why it can save you money to hire an architect.
Once you and your architect determine that an off-grid solar PV system is the right solution for your project, the size of your system will be based not on the square footage but on your annual energy consumption, which is heavily influenced by the shape, orientation and quality of your building?s construction. The solar exposure of your building?s roof becomes very crucial in making a decision regarding any solar application.
To do your own research, there are countless options available online. One helpful tool is this Off-grid Energy System Size Calculator.
Searching for "off-grid kit affordable solar" offers a 320-watt off-grid power system that you can order online.
Unless you are a qualified professional such as a certified electrician, it is not recommended to install an alternative energy system yourself. Professional installation guarantees a successful inspection and provides the owner with a warranty should the system not perform as intended.