* no cost: you can take this action without spending money.
$: it is estimated that you will need to spend between $1 and $100 before you start seeing both energy and dollar savings from this action.
$$: it is estimated that you will need to spend more than $100 before you start seeing both energy and dollar savings from this action.
$$$: it is estimated that you will need to spend more than $1000 before you start seeing both energy and dollar savings from this action.