Roof Vents

As I write this today, it is currently 40.3°C outside, with a projected top of 42°C. For those unfamiliar with Australian slang, this is what we like to refer to as a scorcher. A hot wind is pounding the house, and I’m praying that the ice blocks I put in the chickens’ water this morning keeps them alive until the promised cool change sweeps in.

Welcome to summer in Melbourne, global warming style.

Despite the heat outside, inside the house is still relatively cool, and it is after 1pm. We have a new air conditioner, and I haven’t felt the need to turn it on. While I have no scientific data to back this up, I think the change is due to the roof vents we installed a few weeks ago.

Roof ventThe vents are a simple piece of technology, and because we bought a cheap version ($69 each) they are entirely wind powered. The basic idea is that the heat from the sun is warming the cavity between our tiled roof and the internal ceiling. As the space up there warms, heat starts penetrating our ceiling insulation and warms up the rooms below. By installing these roof vents, the heat trapped in the roof space is able to rise out of the roof and escape, rather than being forced into the area below.

A house the size of ours requires three of these vents, but we only installed two because we don’t want to block any roof space that might be needed for our future photovoltaic system. They work better on a house like ours because we have a pale green roof instead of the more popular black roofs that are sweeping the city, which means some of the heat is reflected instead of being absorbed.

In winter we might end up with the problem that we’re extracting heat that we would prefer to keep in the house. The nice thing about this installation is that it only took about an hour to set everything up, and we still have the missing roof tiles stacked out of the way. If they aren’t working for us during the cooler part of the year, we can simply take them down again and store them until next summer.

If you’re playing along at home…

… are you able to install roof vents in your home to keep it cool during the summer months? If you have already done this, please share in the comments below how well they worked for you.