95 Metro questions

Ok I have a 95 metro 1.0 with 178000 miles before I rebuilt the engine. I put new rings, bearings, all gaskets, honed cylinders, valve job, all new seals, cam, tappets, valves/guides, thermostat, radiator cap, hoses, all new parts. I fired it up and runs GREAT! However I have a problem. The heater only blows hot air while the engine is revving. If it is idling it blows only barely warm air. I have a 180 degree thermostat and a 60/40 antifreeze mix cause lately it has been 35 below zero here. Now will putting a 195 degree thermostat help this or is it just too cold to heat this thing up?? Any other suggestions as to why this may be happening?? Help would be great cause as I said it is COLD here...burrrrrr. BTW if anyone ever questions rebuilding one of these do it, it is VERY easy and for all parts and machine work it was only $750 and a little of my time.

what does your temp gauge read after it warms up?

what does your temp gauge read after it warms up?
Stays right in the middle where it always has ever since I've owned it