I didn't want to hi-jack Guzzi's topic but this question is similar. 

I'm currently staying at my sisters townhouse in Boston while I get some medical treatment.

Her 140 year old, brick townhouse is 4 levels: three stories and a finished basement with lots of plaster and brick walls.  She rents both the finished basement and top floor rooms on AirBnB and is doing well but decent WiFi distribution is a problem.  Strong WiFi is really important to her guests and hers is very inconsistent around the building.  Her cable internet provider is Comcast and it uses a Comcast provided router.

What are the best options for this kind of situation?  I checked out a "Luma Surround System" designed for similar situations but very expensive at $400.  What do most multistory guest houses use?

I'd talk to neighbors, look in some U.S. networking forums, to see what people are using or would recommend.

 

Ideally I guess I'd run ethernet from the current CPE location up to the top floor, and pop in an inexpensive WiFi AP/router, and do the same for the basement, but I'd really have to look the place over. I guess you could service the basement unit with the Comcast device (along with an ancillary WiFi AP/router possibly) from the ground/first floor, and then run ethernet up to the top floor and install a WiFi AP/router.

Assuming that all levels of the house share the same electrical supply then something like this should do the trick for under 100USD.

 

https://www.amazon.com/NETGEAR-PowerLINE-Wi-Fi-1000-PLW1010-100NAS

 

Also has the advantage that it can be easily unplugged and moved to other room/areas. And you can add a second wifi unit in another part of the house very easily also if you wish.

 

As always with Powerline products you have to suck it and see to know whether it will work in your house, so best try to borrow one first or get it on sale or return.

Thanks for both helpful responses.  I had forgotten about Powerline adaptors. I believe the wiring is central.  A problem could be like most old houses, outlets are in short supply.

I think I will first try to get her on a better service deal...see what comes with it.