The former Championship club, who played against Chalmers’ old side Melrose in the British and Irish Cup, stepped in when the former Scotland stand-off quit his new role at Chinnor RFC in Oxford.
Chalmers last night told The Scotsman: “It might look like I’ve jumped ship for a better club, but that’s not the case.
“Of course I knew how far I had to travel to Chinnor when I took on the job, but the reality was that the commute in traffic down here could double and treble the time to nearly three hours sometimes, and that changed the dynamic of it.
“I was having to take time off work to get there in the afternoon to sit about for evening training, just to make sure I was there.
“It had been preying on my mind for a while and then an opportunity arose at Esher, which is just 15 minutes from my home, and I spoke to both clubs.
“It made sense for me to leave Chinnor, which I do feel guilty about, but when I do something I have to do it properly and, hopefully, I can do that now with Esher.”
The 44-year-old, who claimed league and cup successes with Melrose, headed south primarily due to work commitments but also after having several applications for professional club jobs in Scotland turned down.
The SRU have now created new opportunity for coaches with Ayr’s Kenny Murray being appointed to Glasgow’s staff and another club coach expected to join Edinburgh this month.
Chalmers retains ambitions of a return to pro rugby, but will this season join coaches Chris Kibble and Ricky Nebbett, chief executive Mike Schmid and John Inverdale, the club chairman, in striving to steer Esher back into England’s second tier.