Create Heating and Cooling Zones

At some point in the past, our house has undergone a series of renovations to combine three small rooms into open plan living. While we really enjoy the bright spaciousness of our main room, having it open to the hallway meant that we couldn’t shut off this part of the house to separate out heating and cooling zones.

The benefit of separate heating and cooling zones is that you only have to heat or cool part of your house instead of the entire building. By only adjusting the temperature in the part of the house that you are using, you can save a significant amount of money on heating and cooling costs, and the energy use that goes with it.

Door with glass panelsWe were able to separate our main living area from the hallway by rebuilding the wall that had originally separated the two spaces. This was the wall where the cornice had fallen down, leaving a gaping hole in the ceiling. It was an opportunity to create something better than what had been there before, so we widened the doorway and chose a door with glass panels to retain the natural light in our hallway.

The whole project cost us approximately $600 to complete, and it has made such a difference to the temperature in the house. On colder nights we shut the door, and the heat generated in the kitchen is enough to keep the room warm. During a recent hot spell we kept the door shut, and it stopped heat from flowing through our large, north facing windows into the cooler bedrooms. This passive difference isn’t huge, at only one or two degrees, but already it has been the difference between running the gas ducted heating system and not running it.

If you’re playing along at home…

…are you able to create zones in your home to reduce the amount of energy required to heat and cool the space? Please share in the comments below the approach you took and the results you achieved.

Insulating Behind Wall Panels

As part of our solar installation, we needed to get the asbestos removed from the work site. The main areas were our electrical switchboard and the eaves under the roof. We also had two asbestos panels beside the front door, and the company was willing to add those to the job for free. With the exception of the asbestos flue for our hot water system, this now means that the outside of our house is asbestos free.

We saw the removal of those asbestos wall panels as a great opportunity to check the insulation of our external walls, and there was no surprise at all that they were just empty cavities. Walls in this area should have a minimum R insulation value of 2.8 and, since this is a north facing wall, we wanted to go as high as we could.

Adding insulation to the wallThe highest insulation rating that we could find was R 7.0, and we had to get it as a special order, which only took a few days to arrive. We had the right amount of insulation to do the job, but we hit the first obvious hurdle – it didn’t fit. The batts were so thick that it took three adults to compress it inside. Unfortunately, when you start to compress this type of product, you also start to reduce the R rating.

After a quick strategy meeting, we agreed to carefully split the batts down the middle to make them half the thickness. This had the unfortunate effect of reducing their R rating, but it did mean that we could get them in the wall.

Given the price of this insulation, we would have been much better off measuring all of the internal dimensions before choosing a product, so I’m glad that we made this mistake with a smaller quantity instead of buying enough for the whole house. The surplus insulation has been put in the roof where it will be used to patch any gaps once we have a chance to get up there.

If you’re playing along at home…

…do you have any external panels like these that you could remove to add insulation to your external walls? Please share in the comments below if you have made similar modifications to your house and how it went for you.

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.