Planning for semi-detached house, cost estimation

Hello,

...
Price: €249,000 according to the construction service description (which unfortunately I only have as a printout and not electronically)
...
We now have the following extensions/changes in the offer:

Extension to KfW70:

1. Heating system
...
2. additional insulation:
As a note, it states that according to their experience this achieves the KfW 70 efficiency house standard, but proof still needs to be provided.

At first, this all reads coherently; price and note about possible additional costs regarding KfW 70 are fine.

Incidental construction costs (surveyor costs, permits and acceptance, connection fees, earthworks) are indicated at approximately €19,000
Garage and garden work are not listed and will be carried out in-house.

In my opinion, you should quickly say goodbye to this amount; typical incidental construction costs - without additional foundation costs due to difficult soil conditions - are in the range of €35,000-40,000 - without painting work, floor coverings, landscaping, garage, or reserves for extras.
Take a look here:

https://www.hausbau-forum.de/ratgeber/bauherrenhilfe.422/bauherrenhilfe-vor-vertragsabschluss.424/bausumme.662/#Baunebenkosten%20und%20Grunderwerbsteuer

I now have a lot of questions about this:
1. Heating technology - sensible? How ideally to combine with a controlled residential ventilation system (costs?)?

€uro will surely have something to write about this; in my opinion, you should always have a controlled residential ventilation system installed with the currently (tight) construction method.

2. Insulation and KfW70 realistic?

As a basis for the offer: "yes". Further measures - if necessary - only arise after detailed calculation; here the location of the property relative to the sun also plays a role. Your provider has already made you aware of this in the offer.

3. Total costs realistic or can/should something still be done?

If the construction specifications contain no major flaws and appropriate securities are also considered for you as the builder, the costs for the semi-detached house are realistic. I have already addressed the subject of incidental construction costs.

You should not hope for a discount on the sales price. If your provider wants to accommodate you, it will more likely be through "bonuses" in terms of better equipment ... but don't expect big leaps here either!

Kind regards

Hello,

maybe €uro can really write something after all, here are a few more details about the desired/planned technology:

According to the construction service description, a gas boiler with solar support is installed. I have now had a few more offers calculated by the builder:

"Item 1.2: Since the attic was not offered as developed, the insulation lies on the floor of the attic and will then be placed under the rafters during development. This can be done by you or us.

The sizing of the heat pump is determined by the specialist planner when he exactly calculates the heat demand of the house.

1. Price for underfloor heating with towel radiator instead of radiator heating

Additional cost: €6,380.00

Accordingly, the heat pump including structural measures costs an additional €7,490.00 compared to the gas heating with domestic hot water solar according to the construction service description

2. Underfloor distributor with cabinet as provision for later attic development

Additional cost: €490.00

3. Eff70 variant 1: Gas condensing boiler with heating support solar system, underfloor heating and ventilation system with heat recovery: instead of gas heating with domestic hot water solar according to construction service description 10/09

Additional cost: €17,990.00

4. Eff70 variant 2: Air heat pump with underfloor heating and controlled room ventilation as a combined unit, manufacturer Stiebel Eltron, Lyp LWZ 403-SOL (without solar system) instead of gas heating with domestic hot water solar according to construction service description

Additional cost: €21,150.00
"

At the moment the wording domestic hot water solar and heating support irritate me, especially at point 2., I assume that even with the ventilation system the solar system heats the domestic hot water and not just the heating. Otherwise it would have to run in summer despite the solar collector...

How do the prices look? Are they realistic or is the builder adding a big markup? (Using point 4 as an example: €21,150, of which €6,380 is for underfloor heating, leaving €14,770 for the controlled residential ventilation/heat recovery air heat pump combined unit and installation, whereby the gas solar system is omitted and its price should be credited).

Thank you very much

I am not an expert, but I can only tell you what was told to us: The Stiebel Eltron costs about 20k€ with solar panels. The LWZ 403 - SOL is the version with solar - the one without solar operation is the 403. Either take the one without right away (for the solar panels, better build a photovoltaic system on the roof) or the 403-SOL with solar panels - otherwise it doesn't make sense, right? If you now take the 15k€ according to your calculation + 4k€ for the gas condensing boiler + 3k€ the connection fees you pay less minus 2-4k€ that you need more for ventilation ducts, solar lines, etc., the price matches quite well.

Hello,

I do save the gas connection fees, but these are included in the additional construction costs, not in the price of the builder. And the system is offered without solar modules. According to the website of Stiebel, the device is prepared for solar; I cannot find an LWZ 403 without this preparation.
In this respect, the calculation no longer quite fits... from my point of view.