Tack. So, "husdesign" refers to the process of an architect in designing a house. "husdesignen" refers to the definite version - the house design. I can understand a subtle difference here ( I guess that makes it Swedish in how specific it is ). In English, I would use these interchangeably. "The house design", "The design of the house", and "The house's design"
Actually, I've given it some thought and I think you make a good point. I'd use those interchangeably as well, even though they technically correspond to other Swedish words. And if I needed to say husdesignen, I would be likely to choose an entirely different sentence construction instead.
I think the house design is OK and I've added it now. At the moment, this construction is an accepted answer in some similar cases, but far from everywhere. We have to add every accepted translation manually, so feel free to report them where they're missing by using the Report an error button, but also be prepared that it might not yet be an accepted answer in many (most) cases.