Ahh yeah, argon filled windows. I think those leak about 1% of their argon each year so eventually it's all gone anyways. The efficiency thing is always intere

Ahh yeah, argon filled windows. I think those leak about 1% of their argon each year so eventually it's all gone anyways. The efficiency thing is always interesting to me. The way I see it, quality weather stripping (integrated if possible) and storm windows should get you pretty close to a modern windows. I figure you'll never make back the savings with new windows VS old windows that have been updated to be more efficient. Especially since the majority of your energy bill is not due to heat/AC leaving through your windows.