This was one of the ideas I had in mind when I designed the furniture list. [;)]
The answer is simply to copy the furniture you want to keep from the first home, then paste them in the second home. As their location on the plan will be different in the new plan, make them invisible once pasted by selecting the Furniture > Modify menu item and unselect the visible check box in the modification dialog box. Then make them visible and place them one by one (the visible check box can be used directly in the furniture table too).