considering the weo data of usd trillion for the building sector and usd trillion for other major economies and assuming the ratio allocated to the building sector across region one estimates that usd billion should be spent in the building sector in other major economies from to hence an estimated usd billion year should be spent from to while usd billion should be spent from to do the low levels of ee investment result from a lack of financing or is more complex decisionmaking behaviour at play what do business and asset owners and households really consider in deciding whether or not to invest in an energy efficiency asset with apparently high returns observed incongruity between paper assessment and physical results raises the question of whether ee investments are about more money public or private being made available or whether other factors such as risk perception and project complexity are at play