you can be eaten alive and never see one. i know you don't want to use chemicals but i think until you treat the carpet and sof furnishings, your not going to win this battle. JMHO
If you have got to the stage of pets (& your ankles!) being eaten alive, chemicals are the best approach tbh!
Acclaim is pretty effective & will probably sort the problem out in one go but it is important to read the instructions on the can & follow them to the letter!
You need to vacuum
thoroughly first, picking up (& closely inspecting! lol) & putting away/putting somewhere safe anything on or near floor level.
Then spray, making sure you do along skirting boards, under furniture & into any little nooks & crannies (as this is where fleas like to lurk in between meals!).
Open windows & leave room shut up for a couple of hours, or whatever instructions say. (Do the bedrooms first & work down.)
De-flea any pets at the same time, using Frontline or whatever.
Fleas are attracted to both movement & heat, they prefer nomming on pets but they will nom on humans if hungry enough.
If safe to do so, (i.e. not accessible to pets, children, wobbly old people & so on obviously!), try placing a bowl of water containing a squirt of washing-up liquid with a nearby table lamp (one that emits some degree of heat or it won't work) shining on the bowl, on the floor, by the base of beds. The fleas will be attracted to the heat, hop, fall in bowl......& die!
Keep a small bowl/cup in the kitchen, again with a squirt of washing-up liquid in it (this breaks the surface tension of the water, so they sink & drown in it) & if you catch one of the little barstewards it can be very rewarding to drop them into their soapy slimy cup of doom! lol