Should I consider ‘active cooling’?
We have been getting approached more and more for ‘active cooling’ solutions, such as air conditioning or cooling options within MVHR.
If you are experiencing overheating and considering cooling for your home, we would argue that the first approach is to try to reduce the need for this in the first instance. The majority of overheating risk in UK properties is due to solar gain through large south facing glazing. You can reduce solar gain through glazing by several methods:
An internal blind will reflect some heat from the sun back through the window, but the space between the window and blind can heat up and can create a ‘chimney effect’ which heats the room. With triple glazing the solar gain is less likely to reflect back out, so internal blinds have a limited effect. External shading is up to 10 times more effective at reducing solar gain compared to internal blinds.
This is a fixed metal or wooden louvred panel above the window outside which blocks the hot high-altitude sun during summer but still lets low altitude sunshine enter the house during winter. This can greatly reduce the frequency of overheating.
Inward opening windows and external shutters
These are a common strategy in Mediterranean countries as they are very simple to install and wooden louvred panels can also add a feature to the house.
This sticks to the outside or inside of the window and reduces the amount of solar energy that can pass through.
This is similar to a fishmonger’s canopy outside a shop. More elegant systems are now widely available, and these can make a great shading place outside a kitchen for a garden patio area. We have also seen great examples of properties that have grown plants over a structure to create a similar effect.
A common sight across Europe, they can be either electronic/automatic or manually closed. Meshes in the blind can block light but still allow occupants to see out, and they can be opened to different levels to control the level of natural light and solar gain. External blinds are very effective at keeping out the peak sunlight so the room is cool at the end of a hot day.