By saying a blank house, you mean to say that there are no planets in a particular house in a particular divisional chart or ascendant chart. Right?

Although there are no planets in that house, the house always has a zodiac sign and related Nakshatras in it and throughout the lifetime, different planets transit through the house at different times. Moreover, there are planets in other houses which give their different aspects to the “blank” house, providing various results. Further, the lord of the “blank” house is also sitting somewhere in the chart, giving result according to the placement. So, actually, nothing is blank in effect.

In the universe also, space scientists have realised that the seemingly blank space contains dark matter and the so-called blank space is not blank in actual. On the Earth also, when we say that this space is “empty,” actually, it contains air and sometimes humidity too; so, it is not blank or empty in actual.

So, for correct interpretation, complete birth chart is necessary. Hope you will be able to understand this. If you like my answer, don’t forget to up-vote.

Regards.