Just my opinion here, but when taking a traditional home or an older (80+ years old) and making upgrades to create a green home, you should start with the exterior; walls, windows, doors, etc, rather than appliances and materials (finishes and furniture).

I say this because we are looking at energy costs eventually going up again and if you don't have a sound envelope you are just throwing you money quite literally out the window. I have started the process of upgrading all my windows but realized that there are other issues I have already, like poor insulation, air leaks through my basement, and my garage is a heat sucker.

I have come up with the notion that if I address the exterior of the house first, I may save enough money to address my appliances and finishes over time.

Am I right in this assumption or should I approach with a broader brush right from the start?

I saw a commercial awhile back that said the air quality in the home can be worse than what's outside. Wouldn't a sealed interior only magnify this problem? I know you are trying to say that to reduce energy cost its best to address the envelope, but thermal stability is not the only concern in the indoors.

How do you address the need for clean air exchange if there is at least some air flow through the outside of the building? Do you have to install an HVAC system that does it for you? What about homes without forced air systems that rely on steam heat or electric radiators?

I just don't think its a simple as you state it.

The shell of the home is a good place to start, but you shouldn't just go for it all without looking at the implications. I think that is what TXG is trying to say. If you create this astounding thermal barrier but at the same time create a hermetically sealed bubble that doesn't allow your home to breath, you will have air quality problems, overheating, overcooling, stale air, etc. This may not be a problem with the right equipment like an air exchanger on a forced air system, preferably one that can also exchange heat as it brings in fresh outdoor air.

A home is a toxic place in many instances. We bring in so many substances that are toxic in higher quantities. One little dusty book might not be a problem, but in concert with 100 other dusty books and all the other sources of dust, dust mite, mold spores and the like in the home and how you have a problem.

It is important to look at the whole picture, whether you are starting from scratch or renovating an existing home.

I hadn't thought about that, but where is the balance. I know I want to block the cold from entering or loosing my cooled air in the summer, but now I am hearing that this may be dangerous to my health.

What do I do?