Hi teddywills
As you rightly state PIP is disregarded when household income is assessed.
However, PIP is disregarded in the period it is paid but any monies not used in that period is then classed as savings in the following period. Providing your total savings are less than £6K (if you are under state pension age) then you will not be affected by tariff income.
In answer to your question, if you save your PIP money then it will be classed as savings and you need to declared the savings.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
