Gas condensing boiler plus solar or heat pump

I am currently in the planning phase for our house (140 sqm) and am dealing with the heating. I definitely want to use a controlled residential ventilation system, but I am not sure whether the energy should come from a heat pump (water or brine) or from a gas condensing boiler + solar system. A knowledgeable friend advised me to go for gas condensing boiler + solar, but when I calculate it, a heat pump doesn't cost less either. Which option is likely to be cheaper in the long run, and should a solar system be used more for heating or for hot water?

Have a [Energieberater/Ingenieur] plan and calculate this for you; hearsay will not get you far, as the overall situation including climate, heat demand, annual statistical sunshine hours, coefficient of performance of the heat pump, thermal insulation, and so on must be taken into account.