Near-passive house conquers coldest winter in years

I know, I know. It’s been WAY too long since the last post. Really, I’ve been waiting for a good hook. Here it is: spring! As signs of renewed life emerge in the garden, I can declare we made it through the first winter in this furnace-free house without freezing. In fact, at times it was actually TOO hot (more on that later).

While this was a colder-than-average winter, we used only two of our supplemental heat sources: the heat pump and the pellet stove. The other two, electric floor mats in the second-floor bathrooms and an electric resistance heater integrated with the HVAC system, stood idle. As for the floor mats, they would have been nice to have on when stepping out of the shower or tub, but no one ever thought to pre-heat them. We’ll have to develop better habits next winter. The pellet stove was so fun to operate on super-cold days that we never bothered to use the resistance heater.

On the downside, we spent a good bit of time this past winter fixing glitches in the HVAC system. First there was the ice storm in December when the heat pump’s outdoor unit froze up due to a poorly located defrost sensor. Later we discovered the resistance heater had been mis-wired; it was not connected to a thermostat or integrated properly with the heat pump. As a result, the resistance heater was inadvertently left running for several days, wasting electricity. In addition, our fancy schmancy Samsung thermostats have not been telling the heat pump to shut off when the house is warm enough. That has contributed to overheating, especially on the second and third floors where there is significant solar gain from south-facing windows. Sometimes the kids run ceiling fans in their bedrooms to cool off.

I am not an expert, but it seems that despite their low-tech simplicity HVAC systems for passive houses are basically jerry-rigged affairs. Each heat source is a separate unit that must be made to work in harmony with the others. Human error or a bad component can throw the system out of wack. At some point perhaps, manufacturers will make integrated systems that work right out of the box, but the industry isn’t there yet. On the other hand, as this past winter has demonstrated for us, a well-built house can remain comfortable even if the HVAC system isn’t working perfectly.

We continue to fix other problems. Notably, a repair crew came to replace and tighten the frames on our three swing doors (see photo, below), one of which had a gap in the insulation. The doors were supplied by California-based Serious Materials. Unfortunately, one of the frames has loosened up again so we we await yet another service call.

In the meantime, there has been quite a bit of local media coverage about the house. The coverage has generally been accurate, although some stories contained careless errors and contrived quotes. I trust readers who come across the shoddy journalism will identify it as such. On the whole, it’s amazing how much coverage the passive house movement has been getting in national media in recent months. Perhaps this jolt in public awareness will lead to higher home energy efficiency standards. I’d like to think our building and design team played a small role in raising the bar for U.S. home construction.

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2 responses to this post.

  1. Posted by jimharper on March 19, 2011 at 5:09 pm

    Interesting blog. I found it while researching pellet stoves. I think it hugely important that you are showing what can be done with a “regular” house–not some Buckminster Fuller monstrosity.

    Huge improvements can be made and yet you can still stay far away from the “bleeding edge” in both cost and technology. A house such as yours is more comfortable than a conventional configuration. Less drafty spots. More even temperature. Systematic ventilation.

    Almost 15 years ago I convinced a relative to take the same approach on a new house. Nothing extreme–somewhat more efficient windows, careful sealing, good insulation. They haven’t regretted it. The place is very comfortable and costs peanuts to heat and cool. A lot of people forget that utility bills are typically 20% the cost of homeownership, but unlike your mortgage its all 100% non-tax deductible. After 15 years of spending next to nothing on their utility bills they seem—affluent.

    Reply

  2. Nice Post. Thank you for Sharing..

    Reply

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