I just had a Rheem high efficiency furnace installed. It works fine but the exhaust pipe is loud enough to bother my neighbor about 10 feet away. The installer has checked the unit; it is operating correctly. Is there a muffler that can be installed, or can the exhaust pipe be relocated? Is there some other solution? I hear it in my house but it does not bother me, but I don't want it to annoy my neighbor. What is the solution?

This happens on some installs when houses are close together or not well sound proofed.

It might be possible for the installer to put a 90 degree elbo on the pipe to send the noise down to the ground.

Pictures would be good so we can see exactly what you have.

If the houses are only 10 feet apart, your neighbor should thank you. Now, he can't hear you and the Mrs. grinding uglies...

You may be able to relocate the exhaust but you must conform to the manufacture's exhaust limitations such as lengths, number of elbows, pitch, etc. that are in the install guide. If you get a copy it should spell out exactly what you can/cannot do.