New kitchen tap and low water pressure

[trulskaare]

I recently installed a new kitchen tap which has slimmer flexi hoses to the previous tap. After installing it I noticed the water pressure has dropped everywhere in the house. If I turn the isolation valves for the kitchen tap off, the pressure returns to what it was previously. I don't understand how the tap affects everything else in the house. Would changing the flexi hoses to wider ones potentially fix this issue?