Architect cost estimation

Good afternoon!

We are currently studying the cost estimate from our architect. Not only is it not easy for us to assess the unit prices, but a few points also raise many question marks. Therefore, I would like to ask for your assessment. We are building 180 sqm with a good standard ([Architect Standard]). Somehow, some unit prices seem much too low to me:

1) The excavation for the construction pit at €8 per m³ seems low to me?

Excavation construction pit, construction site without disposal	Shell construction		400.00 m³	€8.00	€8.00
Disposal of soil material	Shell construction		400.00 m³	€45.00	€45.00
Backfilling construction pit supplied material	Shell construction		125.00 m³	€45.00	€45.00

2) We want wood-aluminum windows that also insulate well against noise. That also seems low to me?

Wood-aluminum windows

Windows & doors

80.85 m²

€500.00

3) As sun protection, venetian blinds are to be used. The following was assumed here. That also seems too low to me (unit price for windows without sills). Considering the large amount of glass, surcharges due to incorrect estimates are of course considerable.

Sun protection 339 exterior walls, miscellaneous

Windows & doors

80.85 m²

€200.00

I find that anything but cheap, or how is that to be understood?

The wood-aluminum windows will cost you over €40k according to the estimate + €16k for the [Raffstores].

But I can reassure you if it's too cheap for you, it will certainly get more expensive.

One does not know the details nor the area you come from. If you are not building right in downtown Munich but with fairly normal prices, they are somewhat on the higher side.

In 2017, we paid 3 EURO net for the cbm excavation, disposal was 28 EURO net.
What is supposed to be used for backfilling? For us, backfilling the work areas with washed sand was 15.50 EURO net per ton.

For the windows, plastic/aluminum from Internorm at just under 50,000 EURO gross. However, we have very large window areas and alone 2 large sliding doors which amounted to just under 12,000 EURO gross together.

For sun protection, partly aluminum roller shutters, partly Z-lamella blinds, at about 15,000 EURO gross.

Yes, we are certainly already building a quite good standard. We are not saving on window area either.

What unsettled me were the unit prices for the above-mentioned cost groups. For the excavation of the foundation pit, I read about 20-25 €/m³ for reasonably manageable soil, excluding disposal. We have 8 € listed there. Similarly, I thought I had read from you that for the blinds, the price is rather around 300-350 €/m².

Since we now also need relatively a lot of glass, sun protection, etc., a corresponding misjudgment of the unit price would weigh all the more heavily.

Misjudgment

It is only an estimate, based on values from previous years and possibly current projects of the architect.
If you are lucky, the windows cost only €400 per sqm or even €750 per sqm. In the current construction price situation, this is almost unpredictable.

P.S. Are those net or gross unit prices?