3.2.5.1 Sun blocking
During the hotter parts of the year the secondary heat that windows produce can become too intense. An illustration would be how hot a conservatory can become under a scorching sun. By using different methods of cooling this heat can be reduced, unfortunately this is often a very expensive method. A cheaper and more environmentally acceptable method is to use different types of sun blockers. This helps not only to prevent the secondary heat but also the direct heat. Sun blockers can be placed either outside, inside or between the layers of glass and their efficiency depends on where they are placed.
The best way to place sun blockers is to put them on the outside of the windows. These types can be fixed or movable and come in all different shapes e.g. awnings, sunblinds and porches. Windows sometimes have the advantage of being placed further into the facade, something that gives them automatic sun blocking from the building itself. One disadvantage with fixed sun blockers is that they do not normally cover sunshine during the whole course of the day. This however is not a problem since sunshine often is welcomed later on in the evenings. Movable sun blockers e.g. blinds and awnings often have the capability to cover the whole window if needed, these type of sun blockers should always be installed so that there exists a gap of air in between the window and the sun blocker when in use.
Sun blockers on the inside are not as effective as the outside versions. This is because the secondary heat can still exist as most of the sunshine still gets absorbed by the window. These however are the most normal types of sun blockers as curtains and venetian blinds exist in almost every household.