Women typically run a bit colder than men. Hence women typically like the office temperature a bit higher than men. Offices that are at a temperature of less than 70 degrees have been shown to cause lower productivity than offices that are kept between 70 and 77 degrees. The moment the temperature climbs above 77 degrees, productivity falls again.
It is a difficult balancing act given the different factors at work in each individual office. In our offices, we employ space heaters to balance out the heat. My colleague, for example, is much warmer in his office than I am in mine. I have an exterior, single pane window between me and the negative 20 degree weather whereas he has a larger interior office that retains the heat better.
Striking the right balance to keep everyone comfortable is a challenge. A higher hydro bill is likely the price you will have to pay to permit everyone to be comfortable in their own individual spaces. Increased productivity should be your reward.