We live in an old farm house in cental Ontario and over the past number of years have been doing renovations. Our current problem is a serious draft under the kitchen cupboards whenever there is an east wind. I have tried to attach a jpg file to give some idea of what I am describing.

I am looking for advice and here are the options I am considering so far
1 - apply some kind of external barrier (blue styrofoam board or ???) to the external wall for the winter and remove it in the summer
2 - put some type of insulation in the dead space under the cupboards - there area couple of considerations here (a) sometimes the water pipes to the sink and the dishwasher freeze if is there is a prolonged severe east wind and if I insulate around these pipes it will be very difficult to thaw them and (b) some cupboard sections have drawers and there is no top to the dead space under the drawers.

Is there another possible approach that minimizes the disruption and does not involve major construction?

Thanks for any ideas
Bob