Might want to ask your neighbor to run his pump during the day. Pumps do not need to be on 24/7. Had a pool for 20 years and we ran our pump 6-8 hours a day. In wintertime, can be run less

Maybe if they run it at night, it can act as your white noise generator. Two birds, one stone :crap2:

Ohiobuckeye
 

Windows aren’t insulaters! Might be wrong but sounds like like a sales gimmick!!

All glazing combinations will have an STC rating.
Playing with different airspace’s (thickness of space between layers of glass)and spacer bars ( material that separates the layers of glass will result in achieving better or worse STC rating(sound transmission coefficients).
You should work with a reputable window manufacturer that can then work with their glazing manufacturer or department to get the best rating possible.
On installation backer rod air space backer rod offers the best STC rating around the frame itself.
STC ratings used much more commonly in the commercial glazing industry.

OP is certainly not going to buy his neighbor a new pump!!!

I agree with the anti vibration pad and sound enclosure around the pump. We used them for generators too.
When we added water features to our new birdcage, our neighbor asked that we not light up the side near their bedroom. We understood and enjoy motion sensor lights when we use the birdcage. Less light pollution for space craft viewing too. The pump is behind our birdcage.

There are windows that control outside noise!

Contact a local glass company, tell them you want to replace the insulated glass
in your widows. You need to use a laminated glass insulated unit consisting of 2 lites of laminated glass. This will greatly reduce the sound transmission and be much safer in the event it gets broken. This is a fairly easy install for an experienced glazer and will be much more reasonable than having new windows installed.

My friend put a thick foam mattress topper cut to window size over the window and keeps that curtain closed.

While that might be an acceptable short-term solution, it is not a reasonable accommodation, IMHO. I mean, may as well not even have a window there then.

Ohiobuckeye
 

Space between glass are called Thermal Pane Windows we had to have 2 replaced. Also maybe blocked out a little noise but that not what windows are for, windows are to maintain temperatures in house. If they don’t you’ve been scammed or just got cheap windows from a slick talking salesman!

In MI we lived 8 miles from Oakland Airport, one of the busiest in MI. Those living in airport glide path had the ability to upgrade their windows under government guidelines.
Those windows blocked the noise from the landing jets so well, that you rarely knew there was a jet landing. Now outside was a very different matter.
Have no idea the windows that were installed in those homes, or the cost, because it was partially paid by the county. But for a noise factor they were the most noise canceling windows I have ever witnessed. So they are windows out there research may take awhile.

I am truly sorry that noise is bothering you because there are many pool pumps and certainly many air conditioners buzzing and our homes are much closer to each other, part of the plan to try to have smaller yards to maintain. I will tell you that in the eighteen years we have lived here that many of my friends have lost some hearing. I know that isn't what you would like to hear, but that is a fact. I do recommend Dan at The Village Ear on 466 if you eventually need hearing aids. And I am sorry about the noise being annoying. Ear plugs maybe?

Thinking OP doesn’t need advice on business for hearing aide :girlneener: . My guess is OP hearing is just fine. Or probably wouldn’t have posted complaints about the noise.