DIY Curtains, Pelmets and double thermal layers

Anyone else out there planning to do their own window treatments and trying to get the best thermal protection from same? I'd love a shout out to some links that show how best (I know how to sew curtains!) to choose styles, fabrics etc for best thermal properties.

Eg. Do we go a roman blind under a thermal fully lined curtain with a pelmet on top? Would a pull down blind be better? Two sets of curtains? What about a set of horizontal blinds (wood?) instead?

We're after thermal control, light control and minimal maintenance (two small boys = ruined special tracks or wrecked cords etc if we aren't careful).

I'm planning on doing my own. I'm having double curtain tracks and built-in pelmets, with sheers on the inside and heavier drapes on the outside. For the bedroom, the outside curtain will have total blockout for light control.

I don't think any special lining is required, although I'll check with my architect who knows about thermal efficiency. From memory though, he was more concerned about pelmets than the type of fabric.

I've considered blinds but prefer the look of double-curtains. You can get some very thermally efficient blinds, but they're very expensive.

A curtain fabric with a thermally insulating liner behind it is the best option that way you can choose whatever fabric you like to complement your design with the liner providing most of the thermal efficiency.
Your architect is right in that the pelmets stop the circulation of warm and cold air but the curtains should be considered too as part of the thermal equation.

Stewie

Do curtains need to be floor length?

Stewie that's a great diagram!

But what about here in Brisbane where we usually try to keep the heat OUT more than anything else?

Also if the curtains are floor length wouldn't that stop the circulating problem also?

They would help keep the heat out - not as much as keeping the heat in and if they went all the way to the floor I'd imagine it would have a similar effect as the pelmets but not as effective.

Stewie

I'm confused with that picture / diagram / illustration...

Doesn't hot air rise naturally? So why would it circulate through the curtain rail towards the window? I know cold air is denser and heavier so that drops etc...

I think the idea is that the air next to the window pane gets colder and colder, thus it falls and sucks warm air down.

It is a cumulative effect.
Like EmyN says the warm air becomes colder so sinks but it also drags more warm air with it creating the draught. Once that motion of the warm air sinking then cooling starts it becomes a cycle.
The pelmets stop that effect ( or at least slows it down dramatically ).
It interrupts the airflow.

Stewie

I see fair enough, they should make pelmets for the sides too then haha cause air always moves / rotates to the easiest path... so air would kinda be drawn from the sides and cycles down eventually? once the top pelt is in place probably at a slower rate though I assume.