Wall insulation

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FormulaNova said..
How did this work out?

I recently insulated a skillion roof and the adjacent tiled section with foilboard insulation. Not something I willingly wanted, but there was minimal depth in the roof to insulate and I was worried about moisture in winter as much as anything else. It's an old house, so difficult to retrofit anything.

I must admit, I never really understood the difference between radiant and convection heating, and even now I think its a bit like magic. But I tried these panels anyway as they are a thin layer of EPS backed with aluminium on each side.

To my surprise they made a difference. I am not sure if another method would have been better, but so far so good. They lowered the temperature coming through from the roof into the ceiling. They are impossible to fit snuggly without airgaps so I wonder if they change the efficiency.

Anyone else used these type of boards? Bunnings sell them, but until now I never thought they could be an option.

Not done yet, a few other things took priority. And then when I did have some spare time, it was so hot in the roof space that the last thing I wanted to do was crawl around in there.

Hopefully get around to it soon.

We were lucky enough to live on the coast, arvo seabreezes weren't a problem. In fact the house worked so well, it was cooler inside than out up until dark when it swung SE.
And the house was designed to have good flow, from south to north.
There's also the element of convective air flow. Hopper windows at the highest point and a window or door at opposite end of house downstairs. Hot air goes through the upstairs hoppers, sucking cold air in downstairs.

Here's a chart of how it worked over several years. With no source of heating apart from Northelry sun, and the occasional cake baked in the oven. And no source of cooling apart from late day airflow.
Yes we had to manage the windows, open late and shut early the next day in summer, in Winter they mainly stayed shut. It took 40deg heatwaves to get the house up to 30c. And 8 deg outside to drop the inside to 17

I've been waiting for ceiling fans to come up. The truth is they do the opposite of cooling a room because the warm air rises, so it is near the ceiling. Fan cooling is done best with a horizontal flow of air, minimising the downward mixing from the hot air up top.
My measurements of air in a still room show a 3C gradient from floor to ceiling. If I use an el cheapo fan at waist height set to swing the difference is still between 1-2 degrees.
As Decrepit described the passive way to cool a room is by letting the ceiling air vent at night. My old man's office in western NSW was noticeably cool in summer with very high ceilings combined with windows in a central section that was even higher and acted as a flue to vent hot air. Mind you, it was bloody freezing in winter.

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Mr Milk said..
I've been waiting for ceiling fans to come up. The truth is they do the opposite of cooling a room because the warm air rises, so it is near the ceiling. Fan cooling is done best with a horizontal flow of air, minimising the downward mixing from the hot air up top.
My measurements of air in a still room show a 3C gradient from floor to ceiling. If I use an el cheapo fan at waist height set to swing the difference is still between 1-2 degrees.
As Decrepit described the passive way to cool a room is by letting the ceiling air vent at night. My old man's office in western NSW was noticeably cool in summer with very high ceilings combined with windows in a central section that was even higher and acted as a flue to vent hot air. Mind you, it was bloody freezing in winter.

Interesting... I have some Delonghi vertical fans that I bought when I was in a rental which had no ceiling fans. I have used them every now and then, but haven't noticed the difference to the ceiling fans. I will have to try it. When I have used them it was to get even more airflow on very hot nights.

My assumption is that the ceiling fans are mixing the air and the breeze out the window is clearing it out with cooler fresh air. I certainly agree that the hot air sits in a layer close to the ceiling, but for me the airflow during the night cools me down and the DC ceiling fans are very quiet compared to the Delonghis.

I own a house in the country that was built more than 100 years ago. It also has the very high ceilings and high up windows. I do agree in that it keeps cool, probably as all the hot air just sits at the top, and with 3.6m height, it works well. It's also difficult to heat for the same reason, but again I have installed ceiling fans to circulate the air, so it can actually feel warmer in winter with the fans going.

The windows up high though have been nailed shut and painted over many years ago. I think once people got more worried about security and bugs, they just nailed them shut and forgot about the advantages. If I lived there I might try opening them up and installing screens. It sounds like a good idea in summer. For winter I think it would make sense to use one of the other rooms with a lower ceiling height, just to avoid heating all that air.

I've mentioned before in this thread that this same house used to have many fireplaces in order to heat it in winter and a local was telling me that you would normally keep a fire running all the time. Something that works in the country but not okay in a city.

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decrepit said..

I'm guessing remery is gonna fit a second-order polynominal to the peak monthly outside temperatures decrepit recorded and conclude that ....that..... ..the science is indispuatable - Greta's childhood was indeed stolen from her by YOU.