Sunday, March 17, 2013

Winter Passive Performance: The Experience

As mentioned in the previous post, the project team performed an experiment to observe the NNH's ability to resist winter temperature fluctuations with all heating and cooling systems turned off. Samuel recorded the data, and I recorded the experience of three winter days and nights with the heat turned off!

We selected a 72 hour window with relatively low winter temperatures for the East Tennessee region. According to the high and low temperatures for Norris for February 19, 20, and 21 were:

High (°F) Low (°F)
02/19/13 53 37
02/20/13 44 25
02/21/13 52 28

I only allowed myself to check the high and low temperatures posted for these days, and I did not use a thermometer to check the actual temperature of the home's interior. Most of my experience was during the evening, night, and morning hours as I am at work during the day.
Day one: Tuesday, Feb. 19
On day one I was ready for the challenge. I had really piled on extra blankets the night before and waking up to a chilly room was actually very refreshing. Getting ready in the morning was brisk but invigorating. I did not feel cold at all on the morning of day one.

When I got home the evening of day one, it did feel much colder in the house. I wore extra clothes and a hat, but did not feel like the cold was much of a nuisance. Also, I checked the eMonitor App on my iPhone and was please to see how little energy had been used all day with the heat off.

eMonitor app shows realtime information on electricity usage
Day two: Wednesday, Feb. 20
Wednesday morning the house felt cold but not unbearable. I used the dryer to warm up my clothes and pondered my dependance on electricity.

When I got home on Wednesday night, I really wanted to turn the heat on. Wednesday night was the coldest according to the weather forecast and my determination from day one was already wearing off! I took an extra long shower to warm up and again thought about my dependance on electric heat sources. (I should note here that our hot water is partially heated by solar hot water panels, but is also supplemented by an electric water heater.)
I used the pocket door separating the mudroom and living area to prevent
heat loss when opening and closing the exterior door
Day three: Thursday Feb. 21
According to this should have been the coldest outside temperature during the experiment, but it did not feel as bad as the night before. This might be because of other factors, like having been under blankets all night, the presence of sunlight, or knowing I could turn the heat on that evening!

When I got home Thursday night and turned the heat on I set it to 70° F and the fans to high. It took only about 5 minutes for me to feel the difference. After about 30 minutes I turned the fans to low and turned the heat down to 68°. 
I have found that since this experiment, I have been keeping the heat set to a maximum of 68° or 69°. Previously I had turned it up to 71° or 72° on cold nights. I also noticed that to make up for cooler ambient temperatures, I used the dryer more to heat up clothes and blankets and took much longer showers during the experiment.

I will be interested to see the data from this experiment and learn how cold it actually was in the house. While I imagine the NNH performs much better than average homes in terms of maintaining comfortable temperatures, human perception seems to be the real variable here. I'm thinking of my grandparents (from Maine) and how they would probably laugh at me for complaining about 25°!


  1. sorry to be negative, but what a disappointment. Did the team purposely pick a woman with no insight into what factors influenced the energy savings? Yes we can see that is a toilet and a shower??? Presumably they are low flow, but what is happening to the water after it goes down the drain? Yes a washer and a dryer- what factors went into picking them over others? The one that could heat up her fleece the quickest? No mention of thermal mass, siting, building envelope- oh but they were able to 'source' wood from a 100 year old barn. That's good, cause everything else looked spanking new. What kind of finishes and fill was used? I learned nothing-except I'm cranky when sick, but people...can't we do better? Sometimes you only get that one chance to make an impression!

  2. With all due respect there is a TON of information provided in this blog as well as that answers all of your questions. There is a very progressive water management system - including cisterns and filters that capture waste water for either the landscape and/or even treating it back as potable water (Still in testing stages due to existing environmental laws in the state.) A list of products chosen - including energy efficient washer and dryer. And even a complex building envelope was designed with that includes a rainscreen cladding made of Atlantic White Cedar.