I have a solar thermal 'SolarTwin' panel which uses a small pv panel to power the circulating pump. The sun shines, the water heats and the pump runs. That is until January at -5C when the sun shines, the water is tepid and the pump runs. All the hot water is pumped out of the tank and warms the panel. I made a new controller which prevents the pump running if the panel water is cold or if the tank is already fully heated.
I installed a log burning boiler. It heats the house well but having hauled a few tons of timber, cut, split and stacked I don't need the heat in the house!

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If you want to increase attic insulation yet make it movable and less dusty try putting rockwool in cardboard boxes. The boxes can rest across the joists and are very easy to move for access to pipes and wiring.
To identify the presence and direction of draughts drape a sheet of very fine plastic film over doorways and passages. The film I used is from a decorators and is about 2m wide and is used as dust sheets. It is very cheap. Hang it using low strength masking tape. The slightest draught will cause the sheet to billow . Note which way the wind is blowing and any fires or extractor fans in use. Knowing where the cold air is coming from and where the hot is going to is the first step in stopping the waste.