Loneliness was also a major factor with a third saying they did not have close family that they see often while a similar proportion cited not having holidays as a cause of distress.
But more than a quarter (26 per cent) cited not having an active sex life as a major cause of unhappiness, putting it almost on a par with ill health (28 per cent) as a problem for older people.
By contrast only 16 per cent said they were unhappy because they did not like their home or the area they lived in.
And even fewer, 12 per cent, said they were unhappy because of a lack of mobility or having lost a partner.
"Retirement is no longer seen as a final dwindling countdown in life but a bright new chapter," said Mark Neal, managing director of Homewise.
"As people live longer, they want to be more active in later years which includes continuing on with their sex lives, buying their perfect homes, going on holiday."
He added: "Family and where you live appear to be the main reasons for living a happy life in retirement and it is interesting that is not necessarily all about money when it comes to happiness.
"Unfortunately that is the reverse when it comes to being unhappy where finances seem to be the biggest issue for many."