We went double glazed when we renovated the back end of our late ‘50s house and it’s hard to know what difference it has made. All I can say is that the new section of the house does seem better insulated and cosier than the old section at the front. I doubt the extra expense was worth it in terms of energy savings but it was probably the right thing to do. - Jason
Warmer in winter, cooler in summer, less noise, lower power bills, and no condensation or mould on windows in winter. In this type of climate – hot summer, freezing winter – if you intend to stay a while I recommend it if you can afford it. Power costs are only going to go up. - JDE
Keep your noisy neighbours out and your noisy kids and cheesy Saturday night music In. The durability of them is well worth it in the long run also. Everything comes with a cost and every penny counts when building, but some extra pennies spent in the right areas at the start save a lot more later down the line. - woodalwaysworks
I have 10.5mm panes of glass which reduce outside noise by over 40% and have great energy ratings too. You could consider thicker glass rather than double glazing. - ProjectPete
You might want to consider other options first, like timber shutters? You should get some benefit in terms of better insulation, but if heat is escaping elsewhere then you might not notice any difference. - Kermit
Double glazing should be very effective, but custom ones are expensive. There are double glazing products on the market, but be aware that more commonly advertised ones are generally for temperature control, not sound attenuation.
The difference between the two, is that temperature insulating window panes are set closer together to reduce convectional circulation, which reduces the insulating properties. Sound insulation windows have the panes set further apart, so that the entrapped air between them acts as an air cushion which reduces the air vibration transmission to the inside pane.
Depending on what type of window you have, you may be able to have glass sheets cut to size & fitted to your existing windows. To attain better noise suppression, use thicker glass for the new panes. - Andy_Mann