。
She had an air conditioner installed in her house.
Literal
She [topic-は] house [in-に] air-conditioner [object-を] attach received.
~てもらう ('have someone V for one / get someone to V') is the receive-a-favor half of Japan's giving-and-receiving (授受) verb system. Here it marks the speaker's perspective: she didn't install the AC herself — she had someone else (most likely a service technician) do it for her, and was the beneficiary of that service. エアコン is one of those classic English-origin loanwords reshaped to Japanese phonology — short for 'air conditioner.' Air conditioning became near-universal in urban Japanese homes only in the 1980s and 90s; today it's an essential against the brutal humidity of Japanese summers.