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> modern roofing and DIY heat-rejecting window films What do you use? > nighttime ventilation and daytime closure I do that, it works very well (though depen

> modern roofing and DIY heat-rejecting window films What do you use? > nighttime ventilation and daytime closure I do that, it works very well (though depending on the house, of course), but I'm surprised I don't see it as standard advice for homeowners. Even better, an input at a cool spot (near shady grass, etc.), and output with an exhaust fan at the top; auto open/close based on thermostats outside and inside. > In winter, we heat to a more comfortable target for a few hours in early morning and after dusk. Is the early morning heat for efficiency somehow (or just it's too chilly when you wake up after an unheated night). - Also: Our perception is of it being colder when it's colder outside, despite the thermostat being set to the same temperature - that is, we need to set the thermostat a bit higher to not feel chilled. I wonder if our perception of temperature depends on something like the coldest (micro-)draft more than the ambient average.

saltcured 3y ago
It saves energy to let the house get colder overnight when we can rely on bedding to keep us warm. With a lower differential between indoors and outdoors, there is less total energy lost to the outside than if we held a constant target. I'm only dropping the set point about 5 degrees, not disabling heat entirely. Then the morning heat is to make it easier to get out of bed and start the day. We stop it again to take advantage of the common solar gain. But also, it doesn't take as much heat to feel comfortable once we've eaten and gotten more active for the day. For the roof, it is just one of the "cool roof" compliant asphalt shingle systems, with full plywood sheathing. We did not retrofit radiant-barrier sheathing, as there is fine print that this could overheat the shingles. As far as I can tell, the same performance to reject solar load in summer also reduces radiant loss in winter. Vaulted ceilings feel less exposed on a cold winter night. For windows, I applied Gila "heat control" film found at the local Home Depot. It is a modestly cool gray tint that looks only a little bit mirror-like from the outside, not too different from modern low-e glass. It takes a little practice to get satisfying results with the DIY application. I just used a spray bottle filled with tap water with a few drops of dishwashing soap, rather than any proprietary application fluid. Regarding heat perception, it is air temperature, air movement, and radiant effects. In winter, you may feel colder facing an exterior wall or ceiling than with an extra room or story between you and the outside. Or facing a window versus having heavy drapes pulled shut. This is even if the air in contact with your body is the same temperature.
- wolverine876 3y ago
  Thanks! One thing that works for me: I just turn the heat all the way off at night (or down to ~12 C to protect pipes, but I don't think it's ever gotten that cold inside). I just use more bedding if I need it - I'm generating 37 C, much warmer than desireable, so I just need to trap enough of that heat. Mornings are delightful, and my body retains the nighttime heat from the bedding (in its thermal mass, I suppose). Usually I don't turn on the heat until sundown.

saltcured 3y ago

It saves energy to let the house get colder overnight when we can rely on bedding to keep us warm. With a lower differential between indoors and outdoors, there is less total energy lost to the outside than if we held a constant target. I'm only dropping the set point about 5 degrees, not disabling heat entirely. Then the morning heat is to make it easier to get out of bed and start the day. We stop it again to take advantage of the common solar gain. But also, it doesn't take as much heat to feel comfortable once we've eaten and gotten more active for the day. For the roof, it is just one of the "cool roof" compliant asphalt shingle systems, with full plywood sheathing. We did not retrofit radiant-barrier sheathing, as there is fine print that this could overheat the shingles. As far as I can tell, the same performance to reject solar load in summer also reduces radiant loss in winter. Vaulted ceilings feel less exposed on a cold winter night. For windows, I applied Gila "heat control" film found at the local Home Depot. It is a modestly cool gray tint that looks only a little bit mirror-like from the outside, not too different from modern low-e glass. It takes a little practice to get satisfying results with the DIY application. I just used a spray bottle filled with tap water with a few drops of dishwashing soap, rather than any proprietary application fluid. Regarding heat perception, it is air temperature, air movement, and radiant effects. In winter, you may feel colder facing an exterior wall or ceiling than with an extra room or story between you and the outside. Or facing a window versus having heavy drapes pulled shut. This is even if the air in contact with your body is the same temperature.

wolverine876 3y ago
Thanks! One thing that works for me: I just turn the heat all the way off at night (or down to ~12 C to protect pipes, but I don't think it's ever gotten that cold inside). I just use more bedding if I need it - I'm generating 37 C, much warmer than desireable, so I just need to trap enough of that heat. Mornings are delightful, and my body retains the nighttime heat from the bedding (in its thermal mass, I suppose). Usually I don't turn on the heat until sundown.