Identify this SF hardcover novel circa 1972-1973 Martians, Mariner 9, Fedders, light comedy

Question

In 1972 or 1973 (possibly 1974) I read a hardcover library book that took place almost entirely on Earth, and largely in major U.S. city (probably Manhattan).

This was a light comedy, and is mostly a light, comedic mainstream novel. Not serious. During the story, Mariner 9 begins to orbit Mars, and images the global dust storm on Mars. (Those two events actually happened, which tells me that the novel must have been written AFTER late 1971). A delightful revelation is that unseen Mars-based Martians turned on giant fans to produce the dust storm so as to hide their presence from humanity.

Near the end of the novel a Martian spacecraft lands atop a skyscraper (probably located in the City of New York). On the side of the boxlike spacecraft is the word Fedders. The Martian spacecraft is, of course, disguised as an ordinary, large air-conditioning unit. At the end of the story, perhaps, a man and woman fall in love. They were aware of each other, or, more likely, interacted, throughout the novel.

This novel was probably NOT written by a "name" science fiction author. It was good, and was one of those novels that has one foot solidly in mainstream, light fiction. Fedders is the name of an actual, prominent air conditioning firm.

Answer 1

According to the Kirkus review Bob Ottum's All Right, Everybody Off the Planet (1972) has alien landing in Fedders-like spaceship:

These space people are coming to earth, see (don't ask questions, you're wasting your time), and to ensure a friendly reception they detail an advance man to the staff of Time the-weekly-nexus-of-Earth intelligence. But when ""Bing Walter"" -- cleverly prostheticized to look like the man who reads Playboy -- descends in his star-hopping facsimile of a Fedders air conditioner, he meets with a typical terrestrial foul-up involving Cal Tech, NASA, a wise-ass but linear-minded computer named Rufus, chicks who can't resist his plastic body and, most of all, the inner workings of magazine journalism.