Heat pump from octopus

Hi, got a quote from octopus for an Atherma Daikin heat pump, but delayed installation due to some uncertainty around location. Final bill for me would be about 1k for the whole system for a 5 bedroom house newly built. The downside of this is that the heat pump will end up to be necessarily in the middle of our patio, but I feel that if I don't go for this I might be missing a good deal. Other thing I can get around is how the system can save money if gas is cheaper than electricity by 2-3 times at least and even in cosy octopus, gas is still cheaper. Can someone help me to understand this ?