There seems to be a difference when building subjunctives from the verb "brauchen" when used alone, or in the composite verb "verbrauchen".
Hätten wir überall Energiesparlampen, verbrauchten wir nur halb so viel Strom.
Hätten wir mehr Geld, bräuchten wir keine Schulden zu machen.
Building the subjunctives the other way round then
Hätten wir überall Energiesparlampen, verbräuchten wir nur halb so viel Strom.
sounds disastrously wrong. But the second case
Hätten wir mehr Geld, brauchten wir keine Schulden zu machen.
sounds correct too.
Therefore I do have a considerable uncertainty on how to build the subjunctives here. Duden and Canoonet say that "brauchte" is the correct form. However I hardly hear a subjunctive other than "bräuchte".
Is there any peculiar reason why we treat "brauchen" differently? Or am I only fooled by a regional dialect influence that interferes with my intuition here?