I've been keeping my house much cooler this winter than I previously would have. I have my thermostat set for 50 when I'm out of the house or sleeping, though the lowest I've seen it get is 53. When I'm awake and home I've been keeping it between 54 and 64 in the main living area depending on how frivolous I'm feeling. I've noticed that over time I'm getting comfortable at lower and lower temperatures.

I keep my bedroom heat off and the door closed at all times. I haven't measured the temperature in there, but I imagine it is around 50-54 all the time. I just got an electric mattress pad for Christmas and it is quickly becoming my favorite thing that I own. Preheating it and crawling into a warm bed in a 54 degree house is so amazing, then I turn it down really low for the night and sleep so comfortably.

I've been using my indoor dryer vent when I dry my clothes which raises them temperature in the house 3 to 4 degrees per load, but it is getting way to humid. I have a lot of condensation on my skylights and single pane windows. If I ever make indoor storm windows I'm hoping that will cut down on the condensation, but for now I think I may have to revert back to venting the dryer to the outside.

This quote was from my post on Dec 29th of my estimate of Decembers bill:
"So far the furnace ran 64 hours for the last 19 days, running some estimates of what it was further back this month and up to the end of this billing period which will be 40 days for some reason, I think I'm looking at around 100 therms or so for 40 days, add another 8 for the water heater. 80 therms or so for 30 days would be about $60. The 40 days will probably come out to be probably about $75 I figure."

The bill came, the meter was read at the 35 day mark instead of 40 days. Bill is 86 therms or a few cents shy of $70. So I figured 80 therms for 30 or $75 for 40 days, it seems that my thermostats runtime monitor is just about as good of a measuring device as it would be to walk out to the meter outside through the snow and look at it.

Figuring the water heater at 8 therms and removing the $10.50 of basic service and city fees, furnace usage was quite cheap. Previous owners used 125 versus my 86, so 39 more therms to heat the house. 45% more, wow. I paid 66% what they paid, not bad getting 34% off. I've just finished air sealing all of the upstairs windows. The skylight in the bathroom has the shrinkplastic at the bottom of the opening to air seal it but I'm not convinced that it is either airsealed or well insulated in the pocket above that plastic but that will be taken care of when the attic itself isn't an icebox and I am able to add more insulation to the 8-12" of uneven insulation that is already up there.

I used about 3/4 a can of foam on my three bedroom windows which consist of a large window on the NE side and two smaller octagon shaped windows on the SE side. The 5/8" gap from the other upstaris bedroom wasn't as big in the master bedroom, about 1/2" here or a little smaller but using foam that is not designed to warp and has minimal expansion and the gap takes quite a bit, especially when I am squeezing it back in there about an inch or maybe more since a good portion of the sides of the window frame have the gap going back into the wall. I'm not really noticing any differences in furnace runtime at all at night when comparing it to other similar days but do notice that when the sun is shining in that it makes it feel much warmer in the room versus no sun even when the surface temperatures are the same and the sun isn't coming in directly at me. We'll see the January bill when it comes.

I did a one time test and humidified a room to 60% when it was cold and found the cold spots when the flat paint looked a little shiny, probably not the best way to do it but it seemed to work well. I won't do that again though or with any rooms I didn't airseal since I'd rather not have wet wall insulation. I immediately fired up the furnace and raised it to about 65 from the 45 I temporarily had to dehumidify the house back to 40% and then let it cool off again. I'm going to leave that sort of test to an energy auditor with a thermal imaging camera.

Very userful. Thank you.

Robert (or anyone else), when experimenting with increasing humidity and lowering temperature, did you ever come across a chart or formula which would give apparent temperature for a given temperature and humidity? I found the following chart in one of your posts, but I'm not sure if all the info I need is there and how to read it:
I think I'll invest in a hygrometer if it will allow me to carefully lower the house's temperature without causing a mutiny.

I love America. What country has better National Laboratories than we do?

Humidity and Temperature Perception

Despite Argonne's awesomeness, they didn't answer our question. Meteorologists, and people who are outdoors, are primarily concerned with humidity at high temperatures and wind at low temperatures. I think we're on our own here.

I speculate that saturation temperature (i.e. wet bulb temperature or dewpoint) is a better indicator of sensible temperature than air temperature (i.e. dry bulb temperature). Enthalpy, the energy content of air including the heat of vaporization of the water in the air, is a stand-in for saturation temperature. However, moving around in low temperature / high humidity air feels colder than the hotter, isenthalpic equivalent, probably due to the wind chill effect. Also, in line with what ANL says, you want it to be humid enough that not much moisture leaves the body, but not so humid that it condenses on your clothing. That would make you very cold.

My kitchen windows are the coldest part of the house, and when it's properly cold out, I can't achieve a RH > 40% without condensation. Hence, while I had good success with high humidity / low temperature in December, I've bumped up my thermostat a few degrees for January and February.

Though I'm sure Piwoslaw already figured it out, if you want the above chart in real units, you can look for a metric psychrometric chart.

I was messing around with the controller on my Sealy electric blanket, and I bet others are similar. If I hold down the power button while I plug the blanket in, it automatically turns on, with setting 4. You still need to be able to release the power button if you want some setting other than 4, but it could still be a pretty easy mod for the automation enthusiast.

Very useful information.

Thank you.

-AC_Hacker