Get yourself a digital indoor /outdoor thermometer. It's not NETFLIX but it does make excellent viewing!
Knowing the temp outside and inside helps you activly manage your house. When it's hotter outside than in SHUTDOWN - windows, doors, curtains. This will keep your house cool.
Put the outside reciever somewhere it will never get hit by direct sun (the south-side of the building, under a window ledge is good. The inside reciever can be anywhere you like to look at it.
It helps you understand how well your house is performing. If the thermometer says it's 20'C inside, you should feel warm. If you don't it way be because you are in some skimpy outfit and need to put on a few more clothes or these is a draught. Draughts make YOU feel 4'C cooler than the ambient temperature. If there's draughts there are a million ways to fix them. i've got lots of videos in the draught-proofing section of this website. Such fun ...sort of!