Cost of windows vs brick + gyprock + batts etc

G'day folks

Does anyone know if these days it is more costly to install windows in lieu of cladding (brick veneer) plus the associated gyprock, batts etc? And by how much?

I'd like to put lots of windows in my house for aesthetics, however given build costs these days I wonder if it's more budget friendly to stick with a wall where I have enough ventilation already.

The window is the sliding type and size is 1800x2400, so kind of big.

Gone are the days when bricks and windows were 1:1 replaceable.

Morning Buildnoob

This is a very interesting question.

My first reaction was "yeah off course glass is more expensive" but then i started thinking about the square meter rates we pay for each component here in Sydney, and there is probably not a huge difference.

So here goes as quick reference:

GLASS

1. Standard residential glass & frames - $350/sqm

2. Commercial grade glass and frames - $650/sqm


WALLS:

1. Brick Veneer - $220-250/sqm

2. Framing, gyprock, paint insulation etc could easily be $100-150/sqm

So maybe it is close to a 1:1 scenario if you are choosing residential grade windows rather than commercial or double glazing.

Cheers

Simeon

Unfortunately, It's not that simple
You forgot to add extra overs for internal and external painting, steel lintels, etc to the window price
Then there's what gets taken out the builder keeps the margin and what gets put back in goes in at a higher variation margin.
Home owners are best to have a better detailed breakdown
OT, here in WA 2c double face brick is cheaper
Cheers
Chris

Should probably remember that windows let in and out a lot more heat. You might end up with an uncomfortable house in summer and winter.

I find it funny for window manufacturers to have break down between residential and commercial frames and glazing.

What is really the difference? Would you simply call more quality frames as "commercial"? I am quite sure e.g. ECOECO could deliver you high quality aluminium double glazing for less than $650/sqm which would be still much better solution than any of the single glazed "commercial" frames?

Thanks folks, appreciate your thoughts.

ren_ho , in the BASIX / energy efficiency assessments do insulated walls rate more highly than single unglazed windows? Especially north facing ones?

alexp79, some of the custom builders I've spoken to all go for commercial. I'm sure it looks nicer to have a wider glass pane but it seems to me to be overcapitalising? May be justifiable if you've got picture perfect Bondi or bush landscape to salivate over, but not in the suburbs where the view is next door laundry or a busy street. Not great bang for buck. Just my 2c.

@ashington Homes, thanks for the numbers, interesting. Guess the difference might be those energy ratings (i.e. without having to upgrade everything to double glazed).

Cheers.

Alex

Commercial also have thicker glass, I think its 6.3m versus 4.5 for residential.

Also higher quality hardware and runners which also add to the cost.

We prefer to use commercial on most of our builds as the quality is a lot better.

Cheers

Simeon

The difference between commercial and residential windows is the word. There is no definition of what comprises commercial or what comprises residential, nor what the differences may be.

Windows like everything else have to be suitable for purpose, and this is defined under the standards AS2047 & AS1288. Glass thickness is defined in AS1288 and it's unrelated to residential or commercial. AS2047 is about physical testing, the products are type tested to achieve certain resistance to wind and water.

We have windows in 10 storey high-rise which don't resemble the boxy so called commercial profiles because they were designed and tested to comply, and they not only perform in wind and water, they outperform in energy performance - and that is all without the sub-sill, sub-head and sub-jamb (you don't need these if the design and manufacture are to a high enough standard).

Interesting Ecoeco! So commercial windows are gimmicky and better to go with residential + low e, glazing or custom sized to suit.

Regarding energy efficiency, walls are significantly better than a window and it's a large factor in the NatHERS modelling (that give you the star rating).

For example, a minimum standard timber frame wall would have around R2 in thermal resistance if built properly (fairly cheap to go up to R2.5), while a single glazed aluminium frame would be around R0.16. Even triple glazed is still only R1 to R1.25. So you can see even high performance windows are massive weak points relative to a fairly low performing wall.

The modelling takes this into account. Depending on your climate, it can be pretty hard to meet the 6 or 7 star requirements if you have a huge amount of glazing, especially if it's pointing in the wrong directions.

Great info stonesthrow. Super handy to know.

Out of curiosity how do those fancy houses that grace the covers of architectural digest stay energy efficient? They’re all glass top to bottom every wall.

They are not really energy efficient even if they are triple glazed

How do they pass basix or nathers?

They might still be able to pass BASIX at the low level (6 starts), it is not very hard, esp. if the majority of these huge windows are north facing.

It's a great question. NatHERS is imperfect like any model and I think can be worked around. Having gone through a design of my own with an energy assessor, some things do boost the rating that are questionable and you can also say you're going to build certain things and not actually do it in practice.

I doubt many houses perform to their star rating.

Either way, it's a fact that windows are weak points and you should carefully consider sizing and location.

Great advice, thanks stonesthrow and alexp79.

My front facade will face west, so for aesthetic reasons I’ll be putting in a few windows. My other windows are north and east and I only have a couple facing south (garage and bath).

To make this energy and cost efficient, I plan to low e only the west windows. The big windows and doors will face east where the kitchen and living face the backyard. Bedrooms face north.

Are there any improvements I can make from basix perspective? I’m in suburban Sydney so winters aren’t too cold and summers not overly hot, so dont really see the need for double glazing. I’ll probably upgrade the ceiling and external wall insulation.

Yeah I don't think you need to worry much about getting too much sun in winter given you're in Sydney. I think it's still preferable though.

I would worry about the east and west facing windows though. Low e won't do much when the sun is low and coming straight through.

My advice would be to engage an energy assessor during the concept stage (before you're locked into a design). See how it performs and seek advice on best bang for buck changes to take back to the builder /architect.

Yes, that's it. So called commercial are very low tech, wide and thick. Most residential windows will out perform commercial energywise, and the residential windows will be designed and tested to do what they do best.

I am not a fan of Low-e because it only stops radiant heat, i.e. sunlight. It's a filter for solar heat. Yes it registers on the various softwares, but really, it only affects solar heat gain. Any form of shade preventing direct sunlight will outperform Low-e.

Low-E probably best for windows facing west which are hard to cover

Really noob question - "because it only stops radiant heat" - so what doesn't low e stop? Like heat and noise loss?