Height of Pergola

What is a good height for a pergola?

I'm putting a pergola on the back of a two storey house, thus am not limited by the eaves height as you would with a single storey dwelling.

Possible heights for my situation are anywhere between 2.1m and 4.2m!

Pergola size will be 11.5m x 4m.
Ceiling height of the ground floor of house is 3.0m.

2.4m would be a conventional height, however I was thinking of going slightly higher as it could make it cooler under the pergola?
Should I make it 3.0m to match the ceiling height? Will that be too high and out of proportion with the pergola/deck dimensions?

Thanks

I would be inclined to go a little higher as they do tend to heat up. I guess the balance is between going too low where it feels enclosed an heats up ... and too high so that it doesn't shade properly because of the sun angle. Depends on the orientation.

One other though (although probably not a big deal on a pergola) is to think about standard material lengths. I know I didn't do this very well on my extenion and ended up with more waste than necessary.

Is it pitched or flat?

Thanks OBBob

The Deck/Pergola face North. So far (its our second summer in this house) the sun angle seems good - direct overhead in summer and shining in through the windows in winter.
Pergola roof will be at manufacturers recommended 5 degrees. Profile will be one of the corrugated variants.

As for the material lengths I ended up modifying the deck dimensions slightly to allow me to use a standard 4.2m length for the roofing.

I think I'll aim for close to 3.0m.

thanks!

You shouldn't be paying any more per m^2 for roofing cut to length as opposed to 'off the shelf' lengths. You just have to wait for them to get it in, or have it delivered direct from the factory to you. The timber lengths come in 300mm increments so if you do your ordering right then there should be bugger all wastage regardless of the dimensions. I'd set it out according to the maximum span of the timbers if you're looking to save money. I'd also set the supporting beam flush with the top of the rafters. It looks better than having them sit on top.
As for the height it's a matter of preference, whether you want it to look cosy or open. I'd go for 3m.
2.4 looks a bit restrictive on headroom, and over 3m is a bit high and less protective from rain for my liking.