ᐅ Air-to-Air or Air-to-Water Heat Pump?

Do you have both quotes in writing and with comparable items listed?

Zaba12 schrieb:

Do you have both quotes in writing and with comparable line items?

Unfortunately not.

I have one quote with all line items fully detailed.

The other basement is presented as a "basic basement." Additional items for usage class A would be added to this, which results in an extra cost. However, this is still far off. This information was communicated to me by phone.

Unfortunately, I do not have a detailed construction and performance specification or anything similar for the basement.

That is exactly why I have some concerns and why the basement issue doesn’t feel quite right to me...

Are there particular things one should pay special attention to?

Other than a skilled basement builder who knows their craft?! In addition to the waterproof concrete, we also had metal fibers mixed into the concrete, which our architect insisted on.

Zaba12 schrieb:

Except for a good basement builder who knows their craft?! Besides using waterproof concrete (WU concrete), we also had metal fibers added to the concrete, which our architect insisted on.

In principle, should you just trust the prefabricated house supplier when it comes to basement construction and not outsource it?

But if I know which basement builder my prefabricated house company works with, couldn’t I casually request a quote from one of the largest ready-made basement providers in Germany and have it contracted externally?

That’s what I’m getting at... I think you could save some commissions and extra charges by contacting a basement builder directly.

I think it’s easier to have everything done by the prefabricated house supplier... sure, that’s the simplest way, but probably also the most expensive, right?

Am I going in the wrong direction here, or is something like this feasible?
How did you handle this with your prefabricated house suppliers? Everything completely from one source (basement, garage, landscaping, photovoltaic, etc.) or did you hire specialized external contractors for different parts?

We have a masonry house. We planned it with the architect up to design phase 4 and had our private construction coordinator and the architect request quotes. After that, our construction coordinator took over and coordinated the individual trades. Basically, it was built the way houses were constructed before prefab homes and general contractors became common.

We arranged demolition, garage construction, foundation slab, retaining wall, and earthworks ourselves, partly through companies recommended by the general contractor (GC). (There were significant price differences even then. Demolition was nearly three times the price we actually paid. For earthworks, garage, retaining wall/house wall on the slope side, the difference between the cheapest and most expensive bids was around 200%.) The architect’s services and construction supervision were handled by the GC. Certainly not for free, but included in the overall price. However, mistakes made later can become very costly.

Friends who worked with a different GC had a similar experience.
They contracted cellar work, earthworks, etc., to a company recommended by the GC, while the GC took care of the architect’s services and construction supervision.

Consider carefully which tasks you want and can manage yourself as a non-professional. A shell or turnkey home might be an option for you.
Removing individual trades from the contract often isn’t worthwhile. On one hand, the contract price isn’t reduced by 100%, and on the other, it may delay your completion date. And hopefully, this never happens, but in case of warranty claims, you are not usually covered.

For cellar work, pay close attention to what earthworks are included in the quotes.

Air-to-water heat pump (AWHP) without underfloor heating to be installed = lower construction price, but higher operating costs.
Air-to-water heat pump with underfloor heating to be installed = higher construction price, but lower and more efficient operating costs.