Staying warm in winter and cool in summer – without auxiliary heating and cooling
Story by Trends
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Correct window shading and thermal mass are the two big factors in keeping your house warm in winter and cool in summer
Architect Janik Dalecki from Dalecki Design explains the importance of correct window shading and thermal mass.
Correct shading greatly reduces the inside temperature of your house throughout the warmer summer months, improving your comfort levels without any auxiliary cooling. However, did you know that incorrectly positioned and sized shading could also block out the warming winter sun, leaving you with a fridge for a house during winter?
Window and wall shadings are crucial in reducing unwanted heat gain during the hot summer months. Many people are unaware that unprotected glass is actually the greatest source of heat gain to a house. Effective shading such as window awnings or shutters, eaves, pergolas and even plantings can block up to 90% of the summer heat.
It is crucial that window shading be designed to block out all summer sun, whilst still allowing the winter sun to penetrate deeply into the home. This is easily done through correctly sized and located shading, paired with good planning and good design. Poorly designed fixed shading structures can end up blocking out the winter sun and natural winter heating, resulting in a cool house during summer but an even colder house in winter. During the winter months, the sun is at a much lower angle, which means that with the correct shading devices; this lower angle winter sun can penetrate through or under the shading and enter deep into your home. However, it is a fine balance with the specific shading for each specific window size, location and orientation.
Thermal mass is the ability of a material to absorb and store heat energy. High-density materials such as concrete, bricks, stone and even tiles require a large amount of energy to change their overall temperature. Therefore, they are fantastic materials to use to maintain thermal comfort within your home, when utilised in the right location. However, badly placed thermal mass can worsen the extremes of the climate by storing and radiating heat in summer and the opposite in winter. Good thermal design will moderate the indoor air temperature throughout all seasons of the year.
In winter, the thermal mass stores heat from the direct daytime sunlight and then releases this throughout the evening when the internal air temperature drops. In summer, the thermal mass works the opposite way and should be shaded from direct sunlight. This allows the thermal mass to absorb internal energy from the heat within the air inside the house during the day. The cool night breeze then passes over the thermal mass, drawing out any daytime stored energy, which then in return, cools the overall internal temperature for the day to come.
As you can now begin to see, each of the individual passive solar design elements ties in with one another and, if each are not considered equally, then the overall balance is off. Each factor needs to be addressed and included to ensure your home operates correctly.
Find out more about Janik Dalecki and his projects on the Dalecki Design website.
First published date: 31 August 2017