Hi all,

Im posting this in plumbing as a starting point.

This is a strange problem in our house, but I will try to make it as easy to follow as possible.

We have been in our house for 3 years. It was built in the late 80's.
Previous (original) owner did minimum to the home, took every shortcut to repair anything.

Here is the issue....

When the house starts to get a little warm (usually spring or fall, when the CAC isnt on), the dishes come out of the DW smelling like rotten eggs.
The hotter it is, generally the worse it smells. When the Central Air is on during the summer months (we live in downstate NY), it is never an issue. In the winter months it is also not an issue that I can remember.
The DW'er is a newer Bosch (2 yrs old)with a stainless steel tub. We do NOT have a garbage disposal. We do have a septic tank. (no sewers), and town supplied water that is tasty out of the faucet.
The DW'er is connected to our kitchen sink for waste line. We do not smell anything coming out of the kitchen drain from what I gather. There is a trap under the sink to trap the gases that works properly from what I can tell.
Last year in an effort to do anything i could to get rid of the smell, I put the waste line from the DW up high in the cabinet before it went into the trap. That did nothing. We switched from liquid dish detergent to powder, that did nothing. We bought some DW cleaner stuff that you run through a cycle, that kinda works for a wash or 2, but I think its just masking the issue as it quickly returns.
I spoke with my plumber who is totally stumped, he went through why it WOULDNT be a few things, but has no idea what could be causing the issue only when the house is warm.
Its worth noting that at times the house could get a little smelly (usually when air is stagnant or maybe extremely hot summer days), i have a feeling that might be more air duct related as its a totally different smell and isnt as potent as the rotten smelling glasses and dishes coming out of the DW.
Everytime I read something online about possible causes, it still boils down to why does this only happen when the house isnt "cooler" than when the AC is on? Moisture? Humidity ? Our basement is BONE dry and not in the least smelly. There doesnt appear to be any water around the area by the DW or sink.

Im totally stumped and Im stumping everyone I ask.

Ideas?