Selection of the lifting system - Aqualift F Compact

I hope you can help me. We are currently planning our new single-family house with a basement and are looking for the right lifting system from Kessel. In our basement, we will plan a room as a future shower bathroom for the children and provide the corresponding drainage pipes under the floor slab, but for financial reasons we certainly will not expand it or use it as a shower bathroom for the next 10 years. As another room with wastewater below the backwater level, we only have the technical room with the washing machine, dryer, and a small hand basin.

Our basement builder recommended the Kessel Aqualift F Compact because of the planned toilet in the shower bathroom, which he would like to install right under the floor slab, as this is a "clean and reliable" solution. Since the lifting system, as described, certainly will not need to dispose of wastewater containing fecal matter for the next 10 years, we would prefer to install a different, cheaper lifting system in the meantime and then replace it at a later date with a fecal-capable lifting system like the Aqualift F Compact. I have read that a pump sump is no longer state of the art, so the idea was to install a structurally identical non-fecal lifting system during the basement construction and then replace it after the bathroom expansion in 10 years with a fecal-capable lifting system like the Aqualift F Compact.

Is there a structurally identical cheaper lifting system to the Aqualift F Compact so that we can replace it later easily? What solution would you advise us?

Thank you very much in advance for your reply.

I would use a pump sump. It is inexpensive and easy for anyone to clean and inspect. And if the pump should ever fail, just go to the nearest hardware store and get a new one for little money. However, I would somehow protect the walls from the dirty water (pond liner, plastic tub, etc.) because as I can see here myself, the concrete otherwise gets, let's say, somewhat dirty and this cannot be cleaned anymore, which is certainly not very nice if a lifting station is eventually installed.

I would also reconsider whether a toilet is really necessary down there or if you can do without it. I can say from my own experience that I have never missed a toilet in the basement.

I love my toilet in the basement - so far I use it the most there.

But directly discharging feces into a pump sump is a bad idea - the thing must then be absolutely sealed. Additionally, you must provide ventilation again - that becomes harder to implement.

We have a pump sump, but only wastewater from the shower, sink, and washing machine flows into it. Secured by two pumps that switch monthly.

The toilet is drained via a mini lifting system.

We have a Saniboy for heating, the sink, and the washing machine. It could even handle sewage. It costs €400 and hasn’t caused any trouble in 3 years. In our case, it is installed "surface-mounted" in the basement. If it’s under the floor slab – how do you want to access it then? A sump pump can also quickly mess up the KFW calculation, but it has the advantage: if the washing machine or something else leaks at some point, you can dry out the basement quickly again. My basement builder no longer installs sump pumps, so that option was already off the table for us.

What does that have to do with the KfW calculation?

Thermal bridge? Certainly, but so minimal considering the depth and size. Otherwise, you can just put an insulated cover over it.

What does that have to do with the KfW calculation? Thermal bridge? Certainly, but so minimal given the depth and size. Otherwise, you can just put an insulated cover over it

I’m not up to date on this. The pump sumps I know have a depth of about 50 cm – basically more than the entire floor structure in the basement. In my case, there is insulation under the screed + screed installed -> so you have a thermal bridge of 50 x 50 cm (size of the pump sump). Whether that is significant – no idea – I haven’t looked into it further.