ᐅ Condensing gas boiler combined with solar thermal or heat pump

I am currently in the planning phase for our house (140 sqm (1,507 sq ft)) and am focusing on the heating system. I definitely want to use a mechanical ventilation system with heat recovery, but I am unsure whether the energy should come from a heat pump (water or ground source) or a gas condensing boiler combined with a solar system.

A friend who is an expert advised me to go with the gas condensing boiler plus solar, but when I do the calculations, a heat pump doesn’t actually cost less. Which option is likely to be more cost-effective in the long run, and should a solar system be used primarily for heating or for hot water?

Have an energy consultant or engineer design and calculate this for you; hearsay won’t get you very far, since the overall situation—including climate, heat demand, annual average sunshine hours, heat pump coefficient of performance, insulation, and more—needs to be taken into account.