Insulation question..

[Andrew_A]

I have had two quotes for polymer (old newspaper basically) insulation for my tin roof (steepled ceiling + small crawl space above the 3 bedrooms) of about 80m2 living area roughly.

The thing is that the roof seems to be an excellent heat retainer, too hot during the day and too slow to cool down at night. I have heard from my neighbour who has the same roof that it's quite warm in winter though.

So..... If I get insulation am I risking making it slightly better in summer and slightly worse in winter? Or is there a net gain somewhere? I'm planning on getting aircon anyway and think it might be better giving the insulation a miss.

$1400 and $1100 were the two quotes for polymer insulation... About the cost of a Daikin Inverter Aircon unit!

 

[bernly]

I have had two quotes for polymer (old newspaper basically) insulation

I have never heard anyone suggest that insulation isn't a good idea but have heard a few negatives about insulation material that allows vermin to breed. I hope it's not the type you're talking about!

 

[Andrew_A]

I have never heard anyone suggest that insulation isn't a good idea but have heard a few negatives about insulation material that allows vermin to breed. I hope it's not the type you're talking about!

They put borax and something else in it (like white powder) that kills the bugs apparently.

 

[bas00]

Insulation

Hi Andrew
We've got a 70m2 IP in Rockhampton with a tin roof. Have to disagree about it being warm in winter - it's freezing. Definately too hot in summer and too cold in winter. We've got 2 airconditioners in the house,(not reverse cycle) but they still struggle in the heat. We're looking into insulation, but not sure which way to go yet.
Paula

 

[rossv]

Hi andrew,

I've never looked at the stats, however i'm not a fan of insulation.

What happens in summer? ... It heats a house up during the day and as the sun sets the house takes longer to cool because of the insulation ....

and to make matters worse the gov't has daylight saving, so the aircon needs to run for much longer into the night.

Well, if the gov't wants to extend the hrs of sunlight later into the night then they can expect more power usage ...greenhouse ...etc.

personally i just make sure i've got heaps of aircon ..


rossv

 

[Sootygirl]

RossV, I totally agree. The time it takes for our house to cool down at night, is dramatically different since we had ceiling insulation put in several years ago. Its not unusual to still have the air con on at 10pm after a really hot day. And to make it worse, I havent noticed a big difference in the temp during winter :-(

 

[willair]

$1400 and $1100 were the two quotes for polymer insulation... About the cost of a Daikin Inverter Aircon unit!

Andrew,just another idea to take the heat out of the roof space,why not
look at installing 2 roof spinning wirley tops as long as they are set to catch
the wind and set at the high point of the roof,plus they cost nothing to run. good luck..
http://www.everbreeze.com.au/roof_space_ventilation.htm

 

[Andrew_A]

Hi andrew,

I've never looked at the stats, however i'm not a fan of insulation.

What happens in summer? ... It heats a house up during the day and as the sun sets the house takes longer to cool because of the insulation ....

and to make matters worse the gov't has daylight saving, so the aircon needs to run for much longer into the night.

Well, if the gov't wants to extend the hrs of sunlight later into the night then they can expect more power usage ...greenhouse ...etc.

personally i just make sure i've got heaps of aircon ..


rossv

This is what I have been thinking Ross.

I was surprised by how long it took the place to cool down after a hot day this week, it was quite pleasant outside for several hours whilst it was still sweltering inside despite having the windows open.

Thinking just to add aircon and forget about the insulation.

 

[JFisher]

How well your building retains and expells heat will depend on more than just your roof cavity. Exposed walls on north and west sides will heat up the walls of a house and belt straight in windows in summer, these same windows will also allow winter sun in too to help warm the house, but the heat will cool quickly when it hits the uninsulated ceiling.

Cross flow ventilation within the home will help too, as would ceiling fans to keep air circulating. Basically though the comfort factor will be a combination of many things.

Coming from Mildura where we consistenly get days of 40 degrees and above so in summer no-one would be comfortable without ceiling insulation at least here. Wall insulation is also added where possible and we all still have a/c's. Our conite home was without any insulation when we first had kids so we all cooked during summer and froze during winter. Then, as we renovated, we relined all our walls and where possible put wall insulation in walls as well as in the roof, and a new verandah around the house, so now I don't even need to turn the a/c on until it hits 30 degrees. I know it is not always possible to retrofit many of these things but I am just using our situation as an example. There may be other things you can do to improve your comfort levels with a small financial outlay.

Insulation will not stop your house from getting cold in winter but it will prevent more heat from leaving your house if it is installed. Insulation will not prevent your house from getting hot in summer but it will stop the cooler air within the home from heating up when it is near the adjoining roof space. Don't think from out to in, think from in to out. Look at window coverings etc also. The majority of heat loss/gain is through poor window coverings. You will find that your will use up more energy trying to maintain an even temp inside an uninsulated house, than an insulated one in either season, particularly if it isn't a solar passive design in the first place.

There are many types of insulation available but I don't have enough info on your structure to advise you.
Whichever govt body is in charge of your energy saving initiatives may have some ideas for your consideration. Here in Vic it is the Sustainability Victoria. I am a qualified House Energy Rater in Vic if it gives my advice a little more weight. Sorry about the long post, I tried to keep it short.

Good luck with your home. As you live on the Gold coast it probably means that you will place more emphasis on summer cooling than winter heating, so look for the areas around your home where it is hotest and get some advice on how to minimize summer heat gain. Happy to help where I can, but there are energy consultants in all states now I believe.

 

[Sootygirl]

JFisher {or anyone knowledgeble of such things}, how would you rate roof vents {whirlybirds etc} Do they help in cooling the house? Thanks

 

[JFisher]

JFisher {or anyone knowledgeble of such things}, how would you rate roof vents {whirlybirds etc} Do they help in cooling the house? Thanks

Hi Sootygirl
When I did the FirstRate course at Ballarat Uni the lecturer was asked about whirlybirds. They actually dont factor them in when doing an assessment, but he (lecturer) was of the opinion that unless you had vents under your eaves, so the air could be drawn into the roof cavity thus pushing warmer air up to the whirlybird to be expelled, that they wouldn't make alot of difference.

I tend to disagree somewhat as I think that anything that encourages some air flow within a confined space during hot weather will be beneficial. At the end of the day the lecturer was an engineer and lived in Ballarat, probably hasn't had to endure to many days above 35 degrees to put that theory into practice. My only recommendation would be that you would put it on (or nearest to) the highest points on your roof as this will be where the warmest air will head to.

Also, I would also factor the location of the house. If winter warming is equally important then you may consider installing R2.5 batts or higher to the ceiling as well, or instead of, the air ventilators. If you don't have any ceiling insulation then I would definately say they would make a beneficial difference in summer, but will also keep the roof cavity cooler in winter (and thus your rooms below...hence the insulation debate again).
Hope that helps

 

[George]

Heat is transferred through all the walls, roof and floor.

As mentioned above fixed roof problem, not necessarily will make big difference when walls and windows are transparent to heat, but every little bit counts.

Apparently there is plastic film that can be put on glass to lower heat exchange.

Also 3mm cork can be glued to the wall exposed to western heat, then painted or wallpapered and this in terms of heat exchange will be equivalent to 12 cm of brick if I remember it right.

Do bit at the time and see when it is enough to stop.

 

[Tizzy]

In the 70's my old Dad used to remove a couple of roof tiles during summer to create air flow through the roof space. Later on he installed whirley birds and swore by them. He also cut vent holes under the eaves as Julie talked about and planted trees that shaded the hottest sides of the house. He wasn't particularly green in thinking, just too tight to buy insulation and an air con.