The key word there is currently, and it depends entirely on your local area what your mix of energy production is and how clean that is. There's no net-zero ca

The key word there is currently, and it depends entirely on your local area what your mix of energy production is and how clean that is. There's no net-zero carbon options on the market for natural gas. So installing gas-fired options for heating/cooling means that you don't have the option of choosing from a green energy source. Installing electrical heating means that you do have that option - you can reduce the amount of energy you need through local energy production (solar PV, solar hot water), you can store energy locally reducing the need for off-site generation, and you can choose to purchase power from off-site generators that are cleaner.