Efficiency in a Simple Awning
Climate control is the essence of energy efficiency. From architectural movements like passive cooling and natural lighting to plans to reduce electricity use, interior climate has to be controlled effectively.
There are several factors for interior climate that tie directly into the outdoor climate:
- Heat gain
- Ambient and direct light
- Light color
- UV radiation
One thing that retractable awnings can do is ameliorate the harshest effects of sun light and radiation by simply blocking sunlight before it reaches the structure.
Awnings are more effective than glazing, shades, or other common window treatments because they stop sunlight before it reaches a structure. The key is that, with awnings, there is no heat retention in the walls, which keeps radiating heat even after the sun goes down, because it blocks both direct and diffuse radiation.
And this method is really effective.
A recent study by the Professional Awning Manufacturers Association, covering 17 major cities across the US in two phases, showed that awnings have a significant impact on heating and cooling in a building. Awnings reduce air conditioning use by as much as 77%, reduce heat gain as much as 15 degrees, and lower electricity bills as much as 26%. That is an astonishing increase in energy efficiency, with a relatively small change to a building exterior. Those findings were echoed in an unrelated study by the Canadian National Research Council.
The Energie Report from the European Commission explicitly explored using awnings and other sun shades as a method to control electricity consumption. Their report noted the efficacy of awnings in lowering indoor temperatures (a design called passive cooling), but they noted three factors that can offset the benefits of temperature reduction:
- Natural lighting
- Natural ventilation
- Passive heating
Basically, sun shades have to able to block sunlight when there is unwanted heat gain, but they have to be flexible enough to allow light (to reduce artificial lighting), allow airflow, and allow indoor heat gain when it is desirable (such as autumn and winter). In fact, the increased costs in artificial lighting for offices buildings and passive heating for both homes and businesses can surpass the savings from cooling.
Unless you use retractable awnings.
Retractable awnings are adjustable. The simple act of closing an awning, even partially, can allow in the right amounts of light and heat to balance the internal environment, especially when combined with indoor sensors. The woven fabric of awnings offers a diffused color (good for gentle natural light) and air circulation.
The environmental responsiveness of retractable awnings make them a stronger, more efficient choice for buildings – and the science backs it up.