When you are considering a new build there are a few factors that need to rate highly in your planning to ensure you get the most from your design. The use of natural light and ventilation can greatly impact your home’s energy efficiency. This is a major aspect of house design that in the long run will save you money while reducing your environmental footprint.
The positioning, orientation, sources of daylight, and materials utilised for your build will determine how much you benefit from what nature has to offer. Predominantly solar and the power of wind flow.
Passive design
Firstly, you need to know how the concept of passive design can benefit your home. Passive design is the technique of harnessing the useful characteristics of the surrounding environment to promote natural heating and cooling. The simplest example of this is utilising daylight provided by the sun to light and heat your home naturally. Or positioning your build to capture the natural breeze and create a cooling effect throughout your home.
There are a number of facets to effective passive design including:
- Orientation
The direction of your home will affect the energy efficiency of your home. Generally speaking, to optimise your build the long axis of your home should lie in an east-west direction. With the living spaces facing north.
- Thermal mass
When considering building materials, you should understand how each interacts with heat in the way it’s absorbed, stored, released, and distributed throughout your home. Dense materials such as brick and concrete are highly effective at absorbing and slowly releasing heat back into the room as the day cools. Controlling the amount of daylight that is absorbed by these types of materials will allow you to control how heat is stored and released.
- Insulation
Properly insulated walls, ceilings, and floors ensure heat remains where you need it – inside or outside. High-quality insulation works in tandem with the thermal mass in your build, assisting in the control of heat dissipation.
- Shading
Incorporating strategically designed shade, for example, your eaves, can direct sunlight to specific areas or keep heat from penetrating your home when necessary. This is important for good passive design in controlling how heat is absorbed.
- Windows
One of the most impactful aspects of energy-efficient design is windows. They play a significant role when it comes to excessive heat gain and loss. Planning the size, location, and height (placement) of your windows will determine how much heat is allowed in and out.
All of these components factor heavily in building optimisation when you want to use the natural elements to your advantage.
Natural light
Daylight is the key to optimising the natural light within your home. Harnessing daylight will allow you to reduce energy costs by decreasing your reliance on artificial lighting methods. Designed correctly, and you will no longer need to turn lights on in the middle of the day. Of course, you will need to consider your requirements for embracing the views afforded by your property and your priority for maintaining privacy.
Overall, there are a few basic principles for utilising daylight to take advantage of the benefits of natural light:
- you want to ensure your build allows for the creation of diffused light rather than direct sunlight. Diffused light produces a softer, more even dispersal of light and is less harsh than having the sun blaze directly into your house. This will require you to carefully consider the placement and size of your windows to maximise your use of natural light.
- whilst window glazing is a feature in energy-efficient housing design, over-glazing can actually impact the effectiveness of natural light. Rather than optimising your lighting, over-glazing can cause glare and increase heat in summer. During colder days and through the winter months, over-glazing may also cause your house to lose heat.
Ultimately, daylight works hand in hand with passive heating and cooling and must be balanced correctly to ensure a holistic energy-efficient solution.
Ventilation
Generating an effective flow of air throughout your home can keep your space cool in the warmer months. Orienting your build to capture the breeze, whilst avoiding blustering winds, will allow you to naturally harness the cooling effects of the wind. Strategically situated windows can create a good air flow path that, if designed appropriately, can replace most artificial cooling systems and in turn save you money on your power bills.
There are a few considerations to take into account when positioning your home to catch the summer breeze and avoid colder winds:
- is there a prevailing wind direction
- does the wind change with the seasons
- how strong is wind in the area
- what is your build site’s exposure to wind
- what features of the surrounding environment ie buildings, hills or valleys might affect wind
When it comes to bathrooms and other wet areas such as your kitchen, passive cooling and ventilation alone will not provide enough air exchange to sufficiently remove moisture from your space. You will need to consider additional ventilation sources such as exhaust fans or some form of air extraction system to assist in keeping your home adequately ventilated.
