Lithuanians express these two words home and house with only one word. However, this word doesn't have only one meaning.

A house in Lithuanian is namas. It is a normal noun, it has all the cases, both singular and plural:

vienas namas, (one house)
du namai, (two houses)
trys namai... (three houses)

Man reikia gražaus namo. I need a nice house.
Tu gyveni labai gražiame name. You live in a very nice house.
Mama perka šitą namą. Mother is buying this house.

However, when you want to say home, you use only the plural of the word namas: namai.

Čia yra mano namai. This is my home.
Namuose turiu katiną. At home I have a cat.
Šis katinas neturi namų. This cat doesn't have a home.

Plus, there are two archaic forms left in modern Lithuanian:

namo (to home; means the same as į namus)
namie (at home; means the same as namuose)

Do not mix namo with the genitive case of namas (namo). They are stressed on different syllables!

Vytautas eina namo. Vytautas is going home.
Šis berniukas nenori eiti namo. This boy doesn't want to go home.
Šis berniukas nenori eiti į namus. This boy doesn't want to go home.

Namie aš turiu du katinus. At home I have two cats.
Ką tu turi namie? What do you have at home?
Ar tu jau esi namie? Are you already at home?
Ar tu jau esi namuose? Are you already at home?