And with a heat pump you can even invest in PV and use that to be even more independent and later you can leverage an EV car either by never buying gas again or for storage.
Overall a very smart concept.
But perhaps he lives in a country were energy is very cheap, will stay cheap and is very stable?
But the retrofitting issues can be substantial, particularly when it triggers updated building code enforcement. An older house with natural gas heating and no air-conditioning may need major electrical upgrades to support a heat pump system. Others may require ducts to be replaced. Or, other invasive work to meet newer insulation standards. Some houses might have some fluid-based radiant heating and require rework because it was designed for the higher fluid temperatures of a boiler while a heat pump system would use lower temperatures and higher flow rates.
Also, many homes may be subject to some kind of aesthetic rules which rule out the mini-split systems popular in Asia. The owner cannot just bolt new equipment or conduits to the exterior of the house. Instead, the above retrofitting tasks turn into major renovation jobs to tear apart interior walls.
Well, the calculations from the providers are highly likely to be "optimized". I would suggest the first point one might check is if the given COP is realistic. Usually it isn't.
https://www.seai.ie/home-energy/building-energy-rating-ber/
https://www.gov.ie/en/publication/1ca53-new-energy-efficienc...
By the way there's talk from some gov officials to forbid selling old houses if the BER rating is too low. You will need to spend thousands to get it to some better rating.
The only subsidy is the deduction for hiring household help. If you hire outside help for any purpose, you get a tax deduction based on the wages you pay.
2) Having that heat pump removes the need for a natural gas hookup - and fixed-rate monthly cost that comes with it regardless how much gas is used.
I doubt that anyone has calculated the total cost of owning and operating such a system. It might pay off in a super modern highly insulated home. Otherwise, good luck with these systems. The high upfront and maintenance cost and the expected lifetime of about 15 years make this look like a very questionable proposition to me.