It doesn't matter what temperature you have in the tank or what the heater is producing temp wise , if you have 100 meters of hose on the ground in cold conditions it will rapidly reduce the heat of the water , if you are using just 20 meters it will be a lot hotter , I think the important thing is that it will be a lot warmer than than tap water making the working day easier , anything is better than cold water , we run the boiler flat out summer and winter , never had a problem breaking glass Evan on frosty mornings , in the summer we turn off the boiler at lunch time and the tank is hot for the rest of the day , I have never put a thermomiter in the tank but you wouldn't want to put your hand in it it's that hot