[s1artibartfast]

Thanks for explaining. your are talking about exposure to cost increases relative to your intended purpose.

I hold that still depends on what your alternative investment opportunities are. If you buy the $1M house when you actually want the $2M house, you are still locking in 50% of the cost. Thats a good thing if the alternative investments perform poorly, and a bad thing if the alternatives are better.

[qeternity]

Yep, you are indeed locking in part of the cost, but you are still implicitly net short and thus better off if prices fall vs rise.