I’ll third (fourth? fifth?) the window film solution (or insulating curtains). Regular glass panes have a very low insulation value, especially if they are old and draughty. We have used the window film more than once, and it does a very good job (even with our western Canadian winters ).
You might also need to adjust your expectations; I wear a sweater and slippers and watch tv with a blanket on most nights in winter, because it’s just colder in winter than in summer. Some people like a house heated enough to wear shorts inside in winter, but most of us wear sweaters and use tv blankets.
Generally (in the US at least) the thermostat is in the center of the home where it will tend to be warmest. When the central heat turns itself off, it’s based on the temp at the location of the thermostat. When it’s in the center of the home, the perimeter of the home is going to be cooler than the temp the thermostat is set.
Fans will circulate perimeter (cooler) air with the internal (warmer) air. The net result is that the furnace cycle may run longer, but will heat more air within the home. This will also cause the thermostat to sense overall household air temp as opposed to just the air in the immediate area around it.
The catch is that fans create the sense of cooling when there’s a breeze on you. That’s why ceiling fans pulling air up from the floor work best for this. It’s not that a ceiling fan direction dictates cooler or warmer. But a fan blowing from the ceiling down creates the feeling of a breeze, where blowing up it doesn’t as much.
If there are ceiling fans in the home, set them to blow up and turn them on. If not, a couple fans placed in some strategic areas would help as well.
Also - some furnaces allow a setting for the blower fan only without generating heat. This works as well because the central fan continuously circulates air in the home without always generating heat.
Running fans/the furnace blower only will use more energy though - not as much as turning up the temp. Other suggestions would help as well, without an increase in energy costs.
We have two big skylights in our living room (which has a very high sloping ceiling). The widow openings are probably 3’ deep on the high side and maybe 18" deep on the low side, and the window is at the very top, obviously. We think we lose a lot of heat through those skylights. Can anyone figure out a way to stop it? I suggested getting foam (like squishy cushion foam) cut to slightly larger than the holes and wedging it into the skylight openings and letting tension hold it in… my husband isn’t a fan of the idea. Anyone know of a good solution?
get a roll of transparent bubble wrap (used for packing boxes) leave in roll form (with wrap added or removed to friction fit and roll cut to width) and fit in the cavity. this might work for not huge cavities. it would still allow light through so it could be left in place during the daytime. may only be hugely visible directly underneath.
covering just the lower end at the ceiling surface, while helping, still allows loss of heat through a convection loop in the skylight cavity.
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