In other cases a criterion may be needed, and one frequently used is the payback period.
The housing agency also raised the length of the payback period itself.
The payback period for a small system is likely to be over ten years.
If the hybrid costs an extra $3,500, then the payback period is seven years, the report said.
"The payback period on this program is very short for the taxpayer."
These devices have a relatively long payback period of between two and three years.
At current prices, the typical payback period for an office building in Tokyo is more than 100 years.
This is expected to reduce the payback period for installation costs to about 8 years.
This adds a year or two to the payback period,.
So with the reduced rate, the payback period could be 6 or more years longer than you say.