Making your house more energy efficient can be tough when you also try to conserve the look of a house from 1936. The use of g drain water heat recovery products can be very useful to achieve your cost and energy saving goals.
A number of municipalities in Norway offer free energy saving consultancy services to their inhabitants in the form of a home visit and a report.
Link in Norwegian:
https://www.huseierne.no/hus-bolig/tema/oppussing/energiradgivning-gir-bestillingskompetanse/