Also consider honeycomb (aka cellular) blinds.
Insulated cellular shades are typically considered to have the highest R-values of all window coverings.
Also consider honeycomb (aka cellular) blinds.
Insulated cellular shades are typically considered to have the highest R-values of all window coverings.
Spot on, double or even triple glazing is used in Europe, North America, Japan. Any where it gets really cold and there are rich economies.
The benefit in reducing energy transfer across a window increases as the difference, inside vs outside temperature increases. For most of Australia the differences between comfort and the other side are for most of the year not that great. A half or a third of what Northern Europe experiences. There are other more cost effective solutions that provide a greater relative benefit.
Note Australia’s supply and distribution chains are not very efficient. Products such as double glazing appear to be priced with a luxury premium at around 50-100% above typical costs for a British home, if Grand Designs is a guide.
To get the maximum benefit from double glazing, the rest of the building needs to be well designed and insulated. For Australia this includes importantly shading windows and walls from hot sun. Double glazing does not keep our radiant heat from direct sunshine. Large north facing windows may be great for winter mornings, but they are solar heat traps for summer, hence comments by @grahroll and others on how to reduce the impact. Most of the heat transfer in an Aussie designed house comes through the roof/ceiling, walls, floor, and air movement. The windows can have a significant effect if there are many of them. Think walls of glass louvres or 6m opening patio doors. It then, are not these intended to let the great outdoors in anyway.
P.s. properly fitted external or internal shutters can also be effective in managing heat losses from windows, and may be easier to retrofit than double glazing, for our less severe climate. Keeping direct summer sunlight off the windows and near walls with shade hoods, external screen panels, etc may be just as effective and less expensive for some?
Australia house design has IMHO delivered some of the most ghastly, energy wasteful designs all on the say so of a bunch of stuck up style gurus. They put environment a distant last, not first. Time they retired!
I got a replacement/retrofit double glazing quote not too many years ago and the payback time, prior to installing solar and having $150 pcm electric bills was well over a century no matter how computed. Now that my average power bill is under $40 pcm, with the same cost to install it would simplistically be triple the payback. I have more and larger windows than most, but. The payback is computed against the cost and best case savings from the insulation differences.
New construction is different economics. How many of us would/could retrofit just because it would add some comfort to the interior, or just because they felt it was the right thing to do?
Yes, in Melbourne in a 1960 midcentury timber home, we grew vegetation to shade on the east and west, plus some to north. The eaves were wide, properly architect designed to shade and had ceiling insulation…
So the house was much cooler than expected, no window coverings either.
On selling the Asian buyer cleared all vegetation and it was very hot and much glare.
In Perth fast brewing fruiting vines and perfumed would be good on a pergola for a start.
I would will consider blown in rock wool for walls if I buy another timber house,
IKEA sells a range of translucent insulating white interior blinds …have a double layer with air pocket and cheap.
I think you’ll find that our profit extraction from supply and distribution is unsurpassed!
Can’t help you, I’m afraid. We don’t have a problem with just overhead fans and open windows. No air conditioning. We did add a full-length shady verandah, part insect-screened, to the back of the house many years ago. We do have overhead fans on the dining area of the verandah as well. If all of the windows in the house were louvres (instead of just the main bedroom), it would be even better.
Of course there is a point in shading windows. Each square metre of window, in full morning or afternoon sun, can ad close to a kilowatt to the house’s cooling load.
If that is what you are saying, I did not and do not advocate against shading windows - quite the opposite.
The OP had framed their question in terms of shading windows or aircon. I am saying look at the whole thing and decide which actions will give the best result per dollar spent in your case and do not focus on just the windows.
How would I be telling people not to shade their windows and in the next paragraph go on to describe ways to do it?
Air con would be my choice
You said, “There is no point in shading windows if huge amounts of heat comes in through the roof or in running aircon if the house is poorly insulated.”
If you had instead argued that insulating the house was more important than shading windows, we might have engaged in a discussion of the relative pros and cons of those options.
I don’t see why the one excludes the other. By all means say what you want to say.