The necessity to save energy in buildings has been focused both in order to reduce the use of oil and other imported energy and in order to reduce CO2-emissions. When house owners rebuild their buildings, insulate walls and roofs, exchange windows and install heat pumps and heat exchangers they may get moisture damages and bad indoor climate if they do it the wrong way. The market offers many different ways to save energy but the information to the users is selected to describe possibilities, never to warn of risks. Therefore the National Board of Housing, Building and Planning in Sweden has published an information series that describes different energy saving measures. The examples are shortly described, what can be done, is it possible to save energy and what must be done to avoid damages and other risks.