Opening the windows

[Moussemoose]

My DP tells me I shouldn't open the windows if the heating is on.

I think he is odd AIBU.

I normally open the windows when I get up and throw back the duvet so that the bed airs (beds hold a lot of sweat), pop downstairs to make breakfast for DS, cats and myself. I close up the windows on returning upstairs to get a shower.

Drying of washing using the radiators in the house is a particularly bad idea as the odd litre of water has to go somewhere, typically any cool surfaces (walls etc). You also apparently sweat about half a litre per night so beds need airing.
Thus you must let the damp out at some point during the day. Establishing a routine for doing this when the heating is not on is of course ideal. You can have a 'totally sealed' house if you wish but must establish a time when it is fully aired and dehumidified by one means or another to prevent mould.

We have dehumidifiers. They pull a remarkable quantity of water from the air.

Opening the window for ten minutes does the same job as hours of dehumidifier, believe me. From an energy efficiency point of view it's far better to open the window even if the heating is on!!

I switch the heating off and air the house most mornings, unless it's truly freezing. Bathroom windows get cracked in all weathers. I don't like the thought of stale air, and need fresh air through the house.

YABU. If the heating is on, its on for a reason i.e the control systems say that the house requires some heat input. Having windows open will only mean lost energy and bigger bills.

Even with the windows closed the house will have some purpose built ventilation as well as adventitious ventilation due to small drafts and gaps.

I can't sleep without the window open even a crack. Even in the cold weather.

DH moans and tries to unsubtly close it when he thinks I'm asleep. Heating is not on at this stage. We have a 13.5 tog duvet and he puts a fleece blanket over him too. If he manages to open a window I always wake up boiled.