Rate of winter heat loss in our Passive House (why I'm sleeping better at night)

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For those of you who have been following us for a while, you may remember this post from last winter in our old rental house. I was noticing in that post that our rental unit (an older semi-detached house in central Ottawa) was losing 1 to 2 degrees Celsius in 8 minutes, causing our furnace to short cycle like crazy (it was about -8C outside at the time). 

This morning I looked at our temperature chart from last night. It took our Passive House 3.5 hours to drop from 22C to 21C. The temp outside during that same period dropped from -6.5C to -8C. Our heater didn't come on at all during this time!

 Indoor temperature over 4 hours last night

Indoor temperature over 4 hours last night

 Outdoor temperature over the same 4 hours last night

Outdoor temperature over the same 4 hours last night

What's really cool about this is it demonstrates how protected our house is from power outages or a broken furnace. The old house would have dropped from 21C to -8C in under four hours . Our Passive House would take 101.5 hours for the same drop (4.25 days)—but this wouldn't even be possible because the sun would come out and heat us back up during the daylight hours (we've even noticed moderate heat gains from solar energy on overcast days).

What do you think? It's pretty comforting to know our pipes won't ever freeze while we are away, and that even if he power fails in the winter we would be able to stay in our home for a long time.