House heated

It does sound like an advertisement, but why do you think everything is a lie? We're going to need a little more context to figure this one out.

It sounds as though Sarah is shivering in her cold house and remembering bitterly or ironically the advertisement that caused her to buy/rent it. The quotation is part of that advertisement.
Because one has to to pay for every word or every line in a newspaper advertisement, they are always abbreviated as much as possible, whole phrases being left out. In this quotation the words represent something like:

"the house is heated; it is scrupulously clean; it has all modern conveniences; it must be seen to be appreciated."