"This house is not new."

Translation: यह मकान नया नहीं है।

[EmiliaGibs]

What's the difference between 'मकान' and the other word for home/house?

[vinay92]

मकान refers to the physical building that makes up the house. So, it should always be translated as 'house'.
घर is a more personal word and may mean either 'house' or 'home' depending on the context.

[EmiliaGibs]

thank you :)

[JamesTWils]

Do you know whether it comes from the Arabic word for "place"?

[vinay92]

मकान came to Hindi from Persian, so it's probably from Arabic originally.
घर is a native Hindi word.

[PatrickMun13]

So do I need to put the "है" at the end of the sentence or don't I? I thought a negative statement could do without...

[vinay92]

You can skip the है in negative sentences provided there is another verb in there.
In this sentence, है is the only verb (नया is an adjective) so it cannot be dropped.

[PatrickMun13]

Thank you, that's exactly what I needed to know.