The impact of shade and light on an enlargement: optimal orientation
- coraliefortin076
- Oct 1
- 8 min read
When considering an addition to your house, cottage, or garage, one of the most difficult challenges is managing light and shade. At Plan Maison Québec, we know that any poorly positioned or poorly designed extension from a sunlight perspective can lead to undesirable effects: overheating, glare, loss of energy efficiency, or even visual discomfort. So, what are the impacts of shade and light?
This article explores how optimal orientation, shading devices, and thoughtful lighting design can transform an addition into a bright, comfortable, and energy-efficient space.
We'll first discuss the fundamentals of sunlight, then the challenges of Quebec's climate, effective shading devices, and finally, concrete recommendations for successfully integrating light and shade into your project with Plan Maison Québec.
Fundamentals: Why Light and Shade Are Critical
Useful vs. harmful sunshine
The goal of good design is to maximize natural light when it is beneficial (for example, in winter) and limit it when it becomes problematic (high solar angles in summer). Useful sunlight promotes visual comfort, reduces the need for artificial lighting, and contributes to passive room heating during the cold season. However, excess sunlight can cause overheating, glare, or thermal discomfort.
The Canadian Centre for Housing Technology emphasizes that shading is a crucial factor in modulating summer overheating in well-exposed buildings. It recommends the use of adjustable external shading devices, used in the summer and retracted otherwise.
Shadow as an active tool
Shading shouldn't be seen solely as a light limitation—it's also a control tool. Fixed sunshades, roof caps, or exterior blinds can filter direct rays while allowing diffused light to penetrate. Well-integrated shading strategies help balance brightness and comfort.
Impact on energy performance
The energy efficiency of an addition depends heavily on light management. In winter, sunlight contributes to natural heat gain. In summer, excess heat requires the use of air conditioning or active cooling. Properly orienting the addition and planning smart solar protection systems reduces overall energy requirements.
For a project subject to the Quebec Construction Code, an addition of more than 10m² must comply with the percentage of openness permitted under Part 11 of the Code, particularly with regard to windows and glazing. This requires a balance between glazed surfaces and energy constraints.
Quebec's climate: issues for light and shadow
Seasonal variability and solar angle
In Quebec, seasonal differences are extreme: in winter, the days are short and the sun is low on the horizon; in summer, the days are long and the sun is high. This requires a nuanced approach to the orientation of the expansion. It will be necessary to capture low-altitude inputs in winter without suffering excessive overheating in summer.
Risk of overheating
Direct sunlight during the warm season can generate considerable heat gain, especially if the glass surfaces are poorly protected. The cumulative effect of the rays passing through the glass can lead to heat accumulation in the extension.
In Canada, the use of external shading is often encouraged over interior shading, as the latter is less effective when the windows are efficient (insulated, low emissivity)—it is more appropriate to stop the radiation before it reaches the glazing.
Natural obstacles and neighborhood
Trees, neighboring buildings, hills, or surrounding terrain can block or diffuse the sun. When planning an extension, these factors must be taken into account. A site analysis (topography, vegetation, adjacent buildings) must be conducted from the very first sketches. At Plan Maison Québec, this is an essential step before designing the extension plan.
The optimal orientation of an extension
Orient the parts according to their use
When designing an extension, arranging rooms according to their orientation is a fundamental principle:
Living rooms (living room, lounge, dining room) benefit most from sunlight from the south (due south or southeast), especially in winter.
Bedrooms can face east or southeast to capture morning light without being subjected to the intense afternoon rays.
Lesser-used or utility rooms (garage, utility room, shed) can be placed to the north, where direct sunlight is less.
Calculate solar overhangs
Roof overhangs, or caps, play a vital role in filtering summer rays while letting in the low winter sun. Properly sized, they provide a highly effective passive barrier. To adjust these overhangs, you must calculate the sun's height during the summer and winter solstices. An incorrect proportion could block out all light in winter.
Windows oriented perpendicularly or obliquely
It is possible to orient some windows at a perpendicular or oblique angle to the extension's facade, in order to avoid direct sunlight but maximize indirect light. This can be useful when the supporting structure requires it or to optimize views.
Constant indirect light
For spaces where soft, even light is desired (workshop, office, reading room), orienting windows to the north is a proven strategy: the light is constant, indirect, and without direct glare. For certain styles, such as shed roofs, this orientation is often used in workshops.
Shadow devices and complementary strategies
Fixed vs. Mobile Shading
Fixed devices (shades, sunshades, awnings) are effective if properly designed, but lack seasonal flexibility. Conversely, movable devices (shutters, retractable exterior blinds, adjustable sunshades) allow shading to be adjusted according to sunlight and needs.
The Canadian Centre recommends the use of movable external shading devices to better control overheating throughout the seasons.
Sunshade Styles
Horizontal, vertical, or adjustable slats can filter the sun at different times of the day. Horizontal slats are best suited for south-facing facades, while vertical slats are more effective on east/west facades to block oblique rays in the morning or afternoon. Adjustable models offer greater flexibility.
High-performance windows and smart glazing
Even with good positioning and shading, the choice of glazing is crucial. Low-emissivity (Low-E) glazing, triple glazing, or glazing with good insulation coefficients (U) minimize heat loss and limit heat gain in summer. In an extension subject to Part 11 of the Code, windows must meet specific insulation coefficients based on the municipality's degree days.
Accompaniment of reflective surfaces
Interior surfaces (light paint, light-colored siding, walls with reflective finishes) can amplify light diffusion. Outdoors, light or reflective surfaces (light-colored concrete, white gravel, reflective panels) around the extension can increase indirect light.
Controlled natural shadows
Strategically placed trees or shrubs provide beneficial natural shade. A deciduous tree, for example, provides shade in the summer and lets light through in the winter. Their placement should be planned so that they do not obstruct the desired solar path.
Design steps with Plan Maison Québec
Site and environmental analysis
Your project always begins with a thorough site study. The topography, slope, shade cast by trees or buildings, and existing vegetation are analyzed to guide the future expansion. Plan Maison Québec conducts this study to ensure your expansion benefits from optimal light while avoiding unwanted shadows.
Solar simulation and sketching
A solar simulation (with the sun's trajectory according to the seasons) allows you to anticipate shaded areas and plan openings as well as solar overhangs. With Plan Maison Québec, we create comparative sketches, showing the impact of different orientations and shade protection.
Selection of openings
We define the dimensions, types, and positions of windows, bay windows, French windows, and skylights, ensuring their thermal performance while ensuring adequate brightness. The choice of glazing, light transmission rate (LT), solar factor (g), and shutter or blind devices are all part of this step.
Integration of shadow devices
Shading solutions—canopies, adjustable ground breakers, and exterior blinds—are integrated into the expansion plan in a way that is aesthetically pleasing, functional, and consistent with the building's architectural style. Plan Maison Québec prioritizes features that promote comfort without compromising the overall aesthetic.
Adjustments and validations
We adjust the proportions, recalculate the overhangs, check the energy coefficients of the openings according to the standards, and validate everything to achieve an optimal compromise between light, comfort, performance and costs.
Fictitious Case Study: Living Room Extension
Let's imagine you want to expand your living room with a southwest-facing extension of approximately 25m². Here's how Plan Maison Québec would proceed:
Land analysis: presence of a neighboring building to the west that could cast shade in the afternoon, a few mature trees to the south.
Solar simulation: we see that in late summer afternoons, the sun coming from the west comes in at close range, which could overheat the extension.
Positioning choice: the extension is slightly offset to the east to avoid the shadow of the neighboring building, and the angle of the glass wall is adjusted to limit the direct entry of western radiation.
Sizing of the horizontal solar overhang: calculated to block direct sunlight in summer, but allow the low winter sun to penetrate.
Installation of an adjustable sunshade or exterior blinds on the west facade to reduce late-morning sunlight. Selection of triple or double Low-E glazing with good light transmittance but low negative solar gain.
Clear interior surfaces and controlled reflection to maximize diffused light without glare.
Validation of energy performance and Quebec opening standards (Part 11) to ensure the extension is compliant.
In this scenario, the extension benefits from beautiful natural light all day long, without excessive overheating in summer, and effectively contributes to passive heating in winter.
Benefits and return on investment
Increased comfort
A well-designed extension, from a lighting and shade perspective, offers superior visual comfort: well-lit rooms, without glare, with uniform brightness. This creates a feeling of space, well-being, and a warm atmosphere.
Energy savings
Reducing the use of artificial lighting during the day and harnessing solar energy in winter can reduce electricity and heating consumption. Conversely, limiting summer overheating prevents excessive use of air conditioning or cooling systems. The initial additional cost of shading systems and high-performance glazing is often offset by energy savings over several years.
Real estate valuation
A well-designed, bright addition enhances your property. For potential buyers, a well-lit, energy-efficient home with well-controlled shadows is a selling point.
Compliance and sustainability
By complying with the requirements of the Quebec Construction Code (particularly Part 11 for openings), you ensure that your extension complies with energy standards. This avoids costly adjustments later and guarantees the building's durability.
Natural light, well-being and health: concrete benefits
A better regulated biological rhythm
Daily exposure to natural light is essential for synchronizing our circadian rhythm, the biological cycle that regulates sleep, wakefulness, body temperature, and several hormonal functions. A well-oriented extension, allowing in morning or midday light, can help improve sleep quality and reduce disorders related to an unbalanced lifestyle.
A better mood every day
Natural light has a direct effect on mood and morale. In a climate like Quebec's, where winter brings short and often gray days, enjoying optimal indoor lighting can prevent or alleviate the symptoms of Seasonal Affective Disorder (SAD). Bright, well-designed spaces stimulate the production of serotonin, a hormone associated with well-being and mood regulation.
Less eye strain and more comfort
Well-distributed natural lighting, without glare or overly dark areas, significantly reduces eye strain. This is especially important in spaces where people work, read, or use screens. Poor light management—particularly intense direct sunlight—can cause discomfort, headaches, and even migraines. Planning the shading and positioning of openings helps achieve soft, stable light, ideal for everyday use.
A natural source of vitamin D
The sun is the primary source of vitamin D, which is essential for bone health, immune function, and the prevention of chronic diseases. While moderate exposure through glass isn't as effective as direct outdoor sunlight, an indoor space bathed in natural light encourages more active time at home and can indirectly contribute to maintaining healthy lifestyle habits.
A healthy and lively atmosphere
Beyond biological aspects, light also influences the perception of space, motivation, and overall comfort. A well-lit addition creates a stimulating, warm, and welcoming environment that promotes emotional well-being. This type of space is also more attractive to occupants
as well as to visitors and future buyers.
Conclusion: impact of shade and light
The orientation of an extension, the right balance of light and shade, and the judicious choice of solar devices are essential elements for transforming your addition into a pleasant, efficient, and sustainable space. Thanks to its regional expertise, Plan Maison Québec is ideally positioned to design plans optimized for the Quebec climate, taking into account your lighting aspirations and your energy constraints.
If you are considering an extension (house, cottage or garage) and want to maximize light comfort without sacrificing energy efficiency, don't hesitate:
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