The analyst, who lives in Gourock, said: "I joined because I used to be on police staff and I have stayed with them.
"The credit union is a handy way to save because the money comes off your salary, the rates are competitive and I like the people."
Mr Mooney has been a member since 2003 and puts away a regular monthly amount.
Mr Mooney said: "I was brought up to always have money sitting there for when you need it.
"When people budget they think about monthly bills, but they often forget about holidays and the bigger payments and unexpected things.
"I have got a young child now, so I can't spare quite as much as I used to, but I still manage £50 a month because you never know when you'll need it.
"Harry is nine months old and he's already got his own account."