A little Architecture Studio was recently invited to write a guest blog post for the Carbon Copy charity which, is an amazing new initiative that is celebrating carbon reduction initiatives taken by community action groups and local authorities. Our post outlines how the acceptable measures under the Government’s Green Homes Grant can be applied carefully with other passive strategies to avoid loss of carbon savings in the future. Here are some thoughts on how we can work our way towards energy efficiency, comfort and well being.
Analysis of Context and Environment
Before commencing design: it is important to evaluate homes in context to obtain a good understanding of how local environmental features such as surrounding buildings and vegetation affect energy use. Considerations should include exposure to wind, access to solar gain, access to daylight, and the effect of shading from neighbouring structures. Regional climates and local environmental features mean homes will behave differently in each location. Climate data should be studied, to understand how energy and comfort in the building now, and how that will change in the future.
1. Orientation and spatial organisation
For energy savings, a general rule of thumb is to relocate infrequently occupied rooms such as utility and shower rooms to the north and living rooms and bedrooms towards the south. For well being, rooms should be placed to support healthy circadian rhythms. Exposure to prevailing winds should be considered to minimise heat loss and optimise natural ventilation.
The thickness, thermal conductivity, and location of insulation material can make a difference to how a building behaves. Insulation acts as a barrier to heat transfer. It is most efficient at limiting heat loss and heat gain if it is placed on the outside of a building.
Installing Low-Emissivity coated double or triple glazed windows can help to reduce both heat loss and heat gain. However, the size and placement of glazing is as important when considering home extensions. Large south-facing windows will offer the most access to sunlight but lead to increased overheating risk. Glazing with fewer mullions and transoms placed high up a room will optimise influx of daylight. North facing windows offer more uniform lighting. Internal layouts (furniture arrangements) should carefully consider access to daylight.
Fixed and occupant-controlled shading can help to reduce solar heat gain in the summer and heat loss in the winter. Fixed bris soliel and deep roof overhangs will limit solar gain but insulated external shutters can help to create comfortable internal environments if closed when outdoor temperatures are at their highest during the day in summer and lowest during the night in winter.
5. Natural Ventilation
If a site is located in an area with reasonably good air quality, then controlled natural ventilation is a fantastic free resource for cooling homes. The creation of ventilation pathways that capitalise on prevailing winds and allow for passive stack ventilation can help to provide comfortable conditions for occupants in the summer.
6. Surface colour and texture
Highly reflective light-coloured surfaces can help to reflect heat and keep homes cool in the summer. Application of white rendered external insulation, white walls and ceilings can improve lux levels and thermal comfort in the summer. Care should be taken that floors are not too shiny to avoid glare. Conversely in colder climates, darker colours can help absorb heat.
Carefully considered planting can enhance biodiversity and contribute to better air quality and wellbeing. It can also offer opportunities to provide windbreaks. Deciduous trees can help to cool and shade homes in the summer whilst allowing in light in the winter. Distance and heights of trees must be carefully considered. Green spaces have been known to lower temperatures in areas suffering from the Urban Heat Island Effect. The inclusion of water bodies can contribute to evaporative cooling on dry summer days. Green roofs also provide cooling and insulation.
8. Building materials
Materials should be considered really carefully. Like food, natural under processed materials are best for our wellbeing. They are also best for the environment because they have the least embodied carbon. Embodied carbon refers to carbon emissions from the energy used to manufacture materials. However, it is also important to consider transportation of materials. We do not all have the luxury of living in rural environments, therefore perhaps if we’re in the city we need to consider recycled materials, in these cases.
These are just a few pointers but if this post caught your attention take a look at ‘101 Rules of Thumb for Low Energy Architecture’; A beautifully illustrated simple little pocketbook, by Huw Heywood. ‘Adaptive thermal comfort: principles and practice’ by Roaf, Humphreys and Nicol; this is a book for the science buffs!