No problem at all - I want to caution I'm far from being an expert I'm just another concerned homeowner who is trying to solve a radon problem.
What I mean by exhaust fans are fans that only remove air from the house, lowering the air pressure inside the house.
I don't know your setup for sure but turning the furnace on may or may not pressurize the house. For example, my house has no fresh air inlet on the cold air return of the furnace (only a combustion air inlet for the burner and it doesn't leak any substantial amount of air into the house), so running the furnace just moves air around, and heating the air inside the house increases the stack effect which seems to cause the radon levels to rise. If you have an outside air inlet it may help, or if you have some kind of fan system actively bringing air into the house that could be even better.
Last weekend I installed a somewhat ghetto mitigation system in my house so I'm hoping I am near the end of my radon adventure. I went around and closed all the windows in the house for the first time in the 4 months since we moved in (literally, they've all been open at least 1" since the day before we moved in) and we are monitoring the radon levels. Hopefully I'll have some results after a couple weeks, though if I see another 2000+ spike before then I'll probably open the windows again and invalidate the test.
We have talked to many radon mitigation professionals over the past 4 months, and even with our spikes into the 2000-4000Bq/m^3 range they all said the same thing, don't panic, keep taking the readings, get an accurate average. They all wanted a minimum of 30 days average as an indicator of whether to do a 90 day test and only then would make a decision on a mitigation system. When our levels got over 1000 we would generally just leave the house if possible, I mean this doesn't work at night, but we'd just spend more time with the kids at the playground or whatever if it was during the day. Outside air has a radon level of about 0-6Bq/m^3 where I live so I figure a couple hours at those levels brings the average exposure down significantly.
For our house, the professionals wanted us to keep the windows closed to get accurate numbers but since we committed early that we were doing mitigation regardless we didn't follow that recommendation.