Measuring, how much power the wireless connection takes

In theory, disabling the wireless connection on my laptop should improve the overall battery life. In fact the battery consumption is a complex process; when I tried to measure, how longer life I could achieve by disabling wireless, I paradoxically got a lower result. Is there any way to measure how much battery juice is given to the network card when wireless is off? Does the wireless off mean that the network card takes absolutely no power? I'm mainly interested in finding out that wireless uses x % of the overall power consumption, but other forms of the result are appreciated too.