Jane Radley, below left, and Virginia Bernard, right, work as administrators in Tower 42 and were enthusiastic about having a smoke-free pub nearby where they could spend their lunch hour.
They normally go to restaurants to eat, but said they would now consider the Phoenix.
Radley said: "I think it's a brilliant idea.
I just hope they can do enough trade, particularly in the evenings, when it's normally packed in here.
I just wish more pubs would do it, I hate going home stinking of smoke."
Bernard said: "I would feel comfortable coming in here on my own.
The fact it's non-smoking helps it have a much nicer atmosphere.
A lot of smokers can be really inconsiderate and wave their cigarettes in your face."
IT consultant and smoker Mark Hawkins only found out it was a non-smoking pub after sitting down and said he would not have otherwise entered the outlet.
"It's going to take a long time to change peoples' perceptions because pubs are the traditional place to come to have a pint and a cigarette," he said.
"If smoking is legal then we should have the right to do it where we want, and pubs are known as smoking places.
I won't come here again, just because I like a cigarette after lunch."
Steven Newson, left, Martin Gillibrand, centre, and Anna Harper, right, work as IT consultants in the City and all welcomed the capital getting its first non-smoking pub.
"I used to come here when it was a Hog's Head and it's a much cleaner atmosphere now," said Newson.
"I hate it when my suit smells after being in a pub.
I think the evenings will tell if it's going to work, particularly Fridays when it's heaving.
At the end of the day, people should have a choice between smoking and non-smoking pubs."
Gillibrand similarly disliked going back to the office reeking of smoke.
"I may come here more often for lunch now it's non-smoking," he said.
"In the day it doesn't matter, but they may have some problems in the evenings."
Harper added: "I often have a sandwich, but I'd consider coming here now.
However, having a seat and a bit of room are more important factors in a pub than smoke for me.