Sure. It very much depends on what type of energy you're using. If you have buildings that are identical in terms of energy efficiency, then let's say one of the buildings is perhaps 30% to 40% more efficient than a conventional building. One uses clean hydro power and the other one uses heating based on fossil fuels, natural gas, or electricity from coal-fired power plants. The building that uses electricity from coal-fired power plants, even though the buildings have equal levels of energy efficiency, increases carbon emissions by 30%. It produces 30 times as much carbon than the other building using a clean energy source. Energy efficiency is not the only measure to assess the carbon performance of a building.
On March 20th, 2019. See this statement in context.