Decarbonizing economic activities requires simultaneous behavioural and technological changes. At the household level, actions are straightforward, use public transit and stay off dairy and meat. The objective here is to estimate the overall climate benefits, in emission terms, of a change towards low carbon lifestyles across Europe. The European Calculator, an integrated energy model, provides the basis for evaluating synergies between lifestyle and technological changes, as well as potential trade-offs. Changes in lifestyles are simulated across a wide range of dimensions - from diets and appliances to travel distances and living spaces - and for each EU Member State by 2050. The results allow us to identify behavioural changes by sector and country that compare with ambitious technical changes in terms of mitigation potential without large trade-offs. We call such scenario Soft Landing (SL). In transportation, the SL scenario of shorter daily travel distances, higher rates of passenger occupancy and shifts in modal share can lead to emission reductions and savings in household investments, comparable to those resulting from ambitious technological shifts. Yet, SL avoids significant increases in electricity generation and material demand. In agriculture the SL scenario includes a shift in current diets towards healthy standards and reduction of food waste, freeing up land that can be used for agroecology. Thus, changes in diets can compensate for the land intensity and yield differentials of conventional vs ecological practices. Other examples of cross-sectoral interactions in the SL scenario shows the potential multiplier effects of low carbon lifestyles.