aim1900 - I am dissapointed you feel that way.
Why not plant trees to replace the ones that once stood where your house now is/will be.
Your pockets will recover but will the planet?
You are only one but there are millions of you!
....do what you want it is a free country, remember though that power will be ever increasing
in cost and so will the gas/coal/fuel deplete
onc_artisan, I feel sorry that you thought me in that way. I think you misunderstood my point. I am not saying I am gonna do nothing on the energy efficiency. I am just asking if it's worth to upgrade it. It's a cost effective problem.
We can put all in to invent the next generation energy tomorrow. But unfortunately, no governments are keen to it at once, not even Obama. There are thousands of different to spend money and to be environmental. You can walk or ride to office instead of driving. You can stop using air con. You can use your washing machine only when it's full loaded. You can take shower less than 5 mins. You can stop using quad-core computer and 50" TV... I agree with ed that planting trees along the walls must be better than having double glaze windows, even if they can't add one more star to your house.
So please please give your real experience, but not just say what the government's booklet says. Let's say, in summer, 6-star house can maintain 10 degrees lower than 5-star house. If only 1 or 2 degrees difference, I would rather buy a hybrid-engine car (if trees can't reduce emission, hybrid-engine car can surely do :0 ) ...