A tiny light You see a tiny light coming down landing on your stomach and lighting you up
The poem starts out slowly with a line as tiny as its subject. The first line is clear enough: there's a small pinprick of light… somewhere. We imagine a little light like a laser pointer, a teeny blip of illumination.
Then we get a repetition of the first line inside of the much longer second line. We hear about a "you," which we can take to mean us, as readers, but whom we can also connect with the "you" mentioned later in the poem, which would suggest that the "you" is the speaker's lover.
This tiny light has a location in the second line—what we can assume to be the lover's stomach. The light lands, as if it were an airplane, on the stomach and lights the person up. We can think of the meaning of being lit up on two levels. One is that, literally, the lover's physical body is illuminated. The other is that it's invigorating the lover emotionally and mentally, giving him or her energy.
The use of the second person ("you") in these lines really makes us, as readers, feel like this little light is on our own stomachs.
Once it lands on the stomach, we can imagine it lighting up the whole body, even though it was originally tiny.
These lines begin the poem, jumping from the title, "Central Heating," to the idea of light, which is indeed warm, and landing on the stomach—a central part of the body. Right away, our minds are opened up to the idea of central heating as more than a way to keep a building warm—it's also a way to warm a body, a person.
Note, also, the way the poem goes from the first, shorter line, to the second, very long line. It's almost as if the first shorter line is the light just coming on, blinking to life, and the second line builds up and onward as the light landing would move to light up someone's whole body. For more on the form of this poem, check out "Form and Meter."
—A woman stretches out like an ascending flare—
Separated by dashes, this line is related to the lines before and after it, but, as the dashes hint, it is possibly tangential, a little side note. This woman could be the "you" lit up by the tiny light of lines one and two, but that doesn't really make sense, because the speaker probably would have just called her "you" instead of going to the trouble of calling her "a woman."
So, we'll imagine this woman stretching out like an ascending, or rising, flare. Think of an emergency flare, warm brilliant bright light, soaring up into the air, and what someone's body stretched out like that would look like. It's a fantastic image, making us think of just waking up in the morning, or loosening up sore muscles.
This is an example of a simile, a literary device which uses the words "like" or "as" to compare one thing to another. It's very surrealist, like something from a dream, to use the image of a flare to describe a person stretching.
This is a positive image—we can imagine how beautiful this woman must be to resemble a light rising to the sky as she stretches.
Over there in the corner a shadow is busy reading Her bare unencumbered feet are much much too pretty
We skip from one woman to another here, except in this line, we hear about her metaphorically. We go from a flare, brilliantly bright, to a corner, a place that is normally associated with darkness, dust, and shyness. But corners can also be quite cozy and safe, which seems to be the case here.
In the corner, a shadow, which we're not surprised to find in a corner, does something that we are surprised to find a shadow doing—reading. It's not only reading, but it's keeping itself quite busy reading, as if it doesn't want to be bothered. We could call this personification—giving human attributes to an object, or saying a shadow could read—but we think it's the other way around, describing a human in terms of something non-human. That means that calling the woman (whose gender we find out in line 5 with the word "Her") a shadow is a metaphor. She is so quiet and reserved that it's as if she were a shadow; she's hardly real.
In the next line we get details that, though this woman is metaphorically a shadow, make her seem more real. We hear about her feet, which are bare, and "unencumbered," or free of weights, worries, or, simply, shoes. Even though they are feet, which many people find disgusting, the speaker finds them pretty enough to merit a repetition of the word "much." They're not only very, very pretty, they're too pretty, perhaps too pretty to bear.
Imagine this moment in the woman's life. Perhaps tired from a long day of work and running errands, feet throbbing from uncomfortable shoes, she's finally taken off her shoes, relaxed in her favorite chair in the corner, and wrapped herself up in her favorite book. She makes herself so quiet, so shadowlike, in the hopes that she won't be disturbed in her peace. Our speaker, though, has caught sight of her, and appreciates the beauty of this moment.