Double glazing is probably well worth the additinal cost if your property is subject to noise (i.e. busy street) or gets a lot of sun due to orientation (especially being Perth)... are noise reduction and insulation your main reasons for considering DG?

Given how much DG you may need, the cost could be quite significant... You mentioned you are renovating, so it may come down to could that additional cost be better utilised elsewhere??  Also, are you planning to rent out / sell the property or to live in.. I doubt whether the additional cost would be warranted in the case of it being an investment property.

oh the thread is already old but allow me to give my feedback for other might used by opinion. By the way, Yes it will worth it and add a remote blinds to have sun protetion for the house or romm where it was installed.