Hooper, 23, has been the subject of two rejected bids from Southampton so far and the Irishman appeared to have Andy Carroll's fee in mind when he joked about his valuation of Hooper as "£35million".
He said: "Whether people think the fee is justified (or not) it's not the player's fault. But we look at that, we look at some of the other prices being bandied about."
He added: "When we have players like Ki Sung-yueng, Beram Kayal, Emilio Izaguirre, Hooper and James Forrest, they are not going to go cheap, that's for sure. They will have to pay proper money."
"I don't need to speak to the board, they know my position," added Lennon.
Hooper showed his quality against Dundee United at Parkhead when his 16th goal of the season and a header from midfielder Victor Wanyama took Celtic back two points clear of Rangers at the top of the Clydesdale Bank Premier League.
Tannadice midfielder John Rankin pulled a goal back five minutes after the break but the Hoops did enough to leapfrog Rangers who had beaten St Johnstone 2-1 at McDiarmid Park earlier in the day.
United boss Peter Houston, who watched on in the stand serving the first of a two-game touchline ban for criticising match officials following their recent defeat by Aberdeen, rued the fact that his side did not get enough crosses into the Celtic box when they had good possession after the break.
"I am really disappointed that we didn't take something from the game," said the Scotland assistant manager. "Celtic will say they were good goals but they were soft goals, especially the second one, we switched off at a corner and that was a left down."
He added: "Don't get me wrong, Celtic created chances, they always do. But when we got the ball wide we didn't get it in the box. I wish we would have done it more and we might have caused them more problems."