@MPG 

You can never rule out walls as a reason to kill WiFi, that said its quite unlikely to be too bad if its wooden walls / studs.  

My first advice for you would be to run the Network Optimiser, its in the Deco app..  it could well be that your new house has more WiFi in the area (neighbours) than your last place so a channel change may help, the optimiser will do taht for you.

  @Philbert thanks for the tip! Have tried it now, and it just says that it works perfect after it ran.

however, when I check the signal strength it's still on the lowest level and keeps loosing it.

is there something else I can do with the settings if the issue is other wifi signals in the neighborhood? Allthough I only get like 2-3 visable wifi as an opt on the phone, and looks like quite far away.

thanks for your help!

  @MPG 

It may not be possible to figure the difference between two houses without visiting them in person, which is obviously not an option.

I can help with basic steps of how to optimally place Deco units at your new house, but you might need to buy more if WiFi coverage with what you have is not sufficient. If you'd like my help, I have questions I will need you to answer:

1. What Deco models do you have;

2. What is the speed of your Internet link;

3. How large is your new house: how many floors and approximate floor square footage;

4. Can you place Main Deco in the middle of the house, and preferably it should be the middle floor, or you are forced to have Main Deco at one side of the house;

5. Weak signal - can you be more specific. Is it weak signal from smartphone to Deco node, slow WiFi speed on smartphone, yellow/red bars for Signal Source in Satellite Decos?

  @Alexandre. 

Alexandre beat me to this, but yes exactly as he said.  If you can do some tests and post screenshots of whatever you can that would help us diagnose this.   

Ideally screenshots of   

1. The airspace from something like WiFi Analyser (2g and 5ghz)

2.  The speed ./ connection you are seeing on your App between the nodes

and anything else you feel important.. thanks  :)