Green cooling?

[ShaunW]

Hi all
I’m moving into a new ppor – the house is just over 50yrs old, double brick construction, Nth/Sth orientation, tile roof with big roof space with older (maybe 15yrs) insulation.
In the recent heatwave here in Adelaide, it’s gotten pretty warm inside (as we do some minor reno work to make it ‘ours’)

I’m considering about various ways to make the house more efficient in energy use, with minor cash investment. Ie making it cooler without shelling out several $K for an aircon (we are unsure about the house’s future – we may bulldoze and rebuild in a few yrs…we’ll see how we feel about the place after a year or two of living in it)

I’m thinking of whirlybirds on the roof to exhaust hot air out of the roof space, building a pergola on the western side and training a vine up it for shading, maybe even construction of a cheap ‘solar chimney’ on the western wall from thin walled, black painted metal pipe.

Has anyone investigated ‘green cooling’ for your homes, or have any other ideas?
Thanks,
ShaunW

 

[BayView]

Most heat escapes through windows (and doors) and ceilings.

Tinted windows with double-glazing, sealing door frames and properly insulated roofs will help a lot.

Double-glazing is not cheap though.

 

[units4me]

The cheapest way to not fry in your house, short of installing AC is to get some awnings or cheap outdoor blinds to cover the OUTSIDE of any windows that face the sun.

If the sun doesn't get onto the glass in the first place, it makes a big difference, regardless of what indoor blinds/curtains you have.

Also, as said above, weatherstrips and adhesive seals around windows/doors are helpful.

And make sure you AIR YOUR HOUSE OUT PROPERLY OVERNIGHT so that the inside temp is not too high inside the house in the morning. Too many people lock their windows/doors overnight and end up with a stinking hot house in the morning, even though it may have cooled nicely outside during the night.

 

[AlmostBob]

had good results with ridge vents,
soffit(sofit?) vents,
and a plastic sheet attached to the underside of the roof rafters linking the two on the north side
makes a solar chimney of the roof, hot tiles heat the air in the space between the plastic and the tile
air is drawn in the soffit and out the roof ridge,
like a whirly bird, with no moving parts

 

[RumpledElf]

And there's all these predictions on the news for 46, 47, 48 in places like Roxby and Port Augusta. We go by Clare on the TV news (it has quite comparable weather) and that is tipped for 43.

Sunlizard sells something interesting, didn't pay much attention to the cooling aspect though, I was more interested in it for the heating aspect - my house is extremely difficult to heat up.

After three weeks of weather where my verandah thermometer has been recording temperatures of 42-49 most days and 53 on the day it got direct sun on it, I don't think there is much you can do about this weather, its just too extreme. We've been hanging out inside running the aircon for half the day, there's just no breeze at night to push the not-very-cool air outside inside despite all the doors and windows open so we've been sticking at about 28-31 inside for weeks, which is much warmer than it is outside at night. I'm supposed to be getting one house ready for sale and one house ready to move into but its just been too hot to do ANYTHING.

What is most irritating is our 'official' weather for this area has only registered 6 days this year over 40, and 5 of those were like 40.5, and one 43, and lots of overnights in positively arctic temperatures. I swear that weather station is in a fridge or something. Yes, I know that station holds all the SA records for cold, but still ...

http://www.bom.gov.au/climate/dwo/200901/html/IDCJDW5074.200901.shtml

 

[ShaunW]

thanks for the tips, I'd not heard of soffit vents, looks very applicable for my situation.
Likewise double glazing on the western side looks like a good (but perhaps expensive) option.
at least it's 'sposed to be cooler this week!

 

[islandgirl]

How bout you put a solar panel on the roof and claim the rebate off the government that way your electricity is free and then you put in airconditioning. I know here in Queensland with the rebate you can put solar panels on your roof for about $1400 (rebates about $8000). Don't know about other states though.

 

[RumpledElf]

Those solar panels at that price tend to be 1kw. As in, they generate 1kw of power at peak. The average airconditioner uses more than that. To get a solar system that has enough grunt to give you 'free' power when you've got appliances like aircon, vaccuum cleaner etc would set you back $40,000 odd. If it only cost you $1400 to get free electricity everyone would have one, that amount of money is peanuts.

My parents have a fairly hefty solar system that cost them quite a lot, they use aircon sparingly, never turn on lights, solar hot water, wood heating, and they still have a power bill every quarter - the GST component is usually bigger than the bill itself ($5 in electricity $15 in GST).

ETA: you do realise solar systems don't work during power failures either? A lot of people think they do. They don't. Only the battery-backed ones do and hoooboy are those ones EXPENSIVE.

 

[vincenzo]

A solar panel that is either not connected to the mains, but only to certain power points, or ones that can be disconnected/switched from the mains, will not be affected during a mains power failure. I would definitely want to whack in a few switches if i had solar panels, because i'd be pissed if i can't use my power when the mains is out

 

[James Allen]

You would be better off putting in evap air con and then taking it out if you are going to knock down the house latter.

If you spend money on glazing and other things you will loose it all when you knock the place down.

 

[AlmostBob]

I remember, ,, , ,,
the biggest thing with the whirly bird, and other vents, was to put in a vent in the soffit(sofit?) (or 2,3) or lower down the roof if there arent eaves to allow the exhaust somewhere to draw air in to replace what was taken out,
any extractor is defeated as soon as partial vaccuum beats the flow the extractor is able to generate.

 

[ShaunW]

Hi, I was amazed when I researched solar panels, and found there is no storage capacity, and you get no power in blackouts. Unless you go down the route of having a big battery system and isolation switch from the grid.
Expensive.
Sort of makes me think all this ‘green awareness’ stuff and the solar rebate is political spin.

In the short term a roof ventilation system coupled with under-eave vents may be the way to go – cool down the roof space via constant airflow, and be reasonably cheap.
Would painting the roof tiles in a light reflective colour also be useful?