Malcolm Beer made his comments ahead of a Windsor council aviation forum later.
He said a third runway north-west of the airport could create the need to use greenbelt land for housing.
A Heathrow spokesman said: "There will be little or no need for additional house-building over and above current local authority plans."
The housing concern comes after a recent report by the Airport Commission, which stated the Heathrow expansion would create between 47,400 and 112,400 jobs by 2030, which in turn would require an extra 29,800 to 70,800 homes to be created in the surrounding area, including Windsor, Slough and London boroughs.
Mr Beer said "anxious" Windsor residents associations would be organising a public meeting in the next 10 days ahead of the commission's public consultation deadline on 3 February.
Mr Beer, who is on the Royal Borough of Windsor and Maidenhead Borough aviation forum committee, said: "We have an enormous housing problem in the area.
"We are having a real problem considering if we have to release greenbelt land for housing, which is an unpopular suggestion.
"Apart from the noise, the whole area will be urbanised - that's what a lot of people don't realise.
"The impact will be felt across the Thames Valley - it's commercial greed gone mad."
The borough council forum will present its own residents' poll plans after a Heathrow report stated most residents were in favour of expansion.
The Heathrow spokesman said the expansion plans would benefit 700,000 existing residents in the area "who are unemployed, under-employed or are commuting out of the area at present".
The aviation forum takes place at 19:00 GMT at The Guildhall Chamber, Windsor.
Creating up to 70,800 homes if Heathrow expansion plans go ahead would cause "absolute turmoil", a Windsor councillor has said.