The biggest issue is if you don’t have the money to buy it, it matters very little about the efficiency and how long it lasts. You still need to pay for it. He could justify the expense because we are a very rural area and land is cheap and tagging it to a new build brings down the interest costs. This is often makes geo-thermal a non-starter for most - as you point out. He even admits he wouldn’t have done it under any other circumstance.