Installing sunshades (movable awnings for instance) is highly recommended for hotels in areas with lots of summer sun. Well designed sunshades will help keep the building cool and comfortable, and will reduce the need for air conditioning.
• Sunshades are a screen against the sun's rays.
• This screen if more effective if it is outside the window, because the sun's rays are reflected before they reach the window glass. When sun protection is inside the window, only a small fraction of incoming solar radiation is reflected back outside.
And some sunshade systems can generate electricity! (They are equipped with photovoltaic modules.)
Exterior sunshades (awnings for instance) are recommended, as they are more effective that indoor protection (curtains etc.) in terms of blocking heat.
Sun protection can be fixed (sunscreens) or movable (awnings). For rooms with eastern or western exposure, movable sunshades are preferable, as they can be folded back in winter to let in sun and heat the indoor space. For southern exposures either fixed or movable shades can be installed. Sufficient winter sun will enter the room even if a fixed sunshade is installed, if the system is properly designed.
Room exposure Recommended type of sunshade
North No sunshade
East and west Movable exterior sunshade
South Movable or fixed exterior sunshade
Fixed sunshades on south-facing walls will protect the hotel from sun in summer while letting in sun in the winter.
Which rooms should be protected, by order of priority?
• For customer comfort, sunshade systems are recommended for rooms with eastern, western and southern exposures.
• Offices with western and southern exposures should also be protected.
What are the appropriate criteria for choosing sunshades?
• Room exposure: the geometric angle between sun and window (i.e. room exposure) must be considered when choosing a sun protection system. With southern exposures the summer sun is high in the sky; the best sun protection is a horizontal shade. With eastern and western exposures, the sun is lower and its rays are almost perpendicular to the window; the best protection is a vertical shade.
• Window type: window size and glazing must be considered.
• Compatibility with summer ventilation: if hotel windows are opened for ventilation and cooling in summer, be sure that the sunshade does not impede ventilation.
• Colour: sunshades should be of a light colour.
• Durability: verify sunshade characteristics in terms of maintenance, wind resistance etc.
• Ease of use: centrally controlled sunshades can be installed.
Approximate payback time:
• Possibly < 5 years.
It should be noted that costs and payback times are highly dependent on the local setting and the initial situation of the hotel.
• Sun protection systems help keep the hotel cool in summer, reducing air conditioning needs.
• In addition, some sunshades can reduce heat loss in winter, thus reducing heating needs. Examples are outside awnings that are closed at night to reduce heat loss.)
Greater comfort in summer:
• Sun protection systems improve comfort in summer and help keep the building cool, reducing the need for air conditioning (which does not always offer the most comfortable form of cooling).
Reduced CO2 emissions
• For a hotel of 1,000 m² that uses 37.5 kWh/m² of natural gas for cooling annually, and applying emission factors for France, a 30% savings in energy consumption represents:
0.63 t CO2 eq of avoided emissions each year
Emission factors for electricity in France: 84.3 g CO2 / kWh.
Emission factors for natural gas in France: 331 g CO2 / kWh (Source: ADEME).
• Ease of implementation: Moderate (**).
• Best time for implementation: at the time of facade renovation work.
• Relevant initial situation: the hotel must be cooled in summer.