Why we should be talking about comfort, not energy efficiency
TreeHugger and just about everybody else in the green movement have spent the last decade talking about the importance of energy efficiency and our carbon footprint. Our general impact on the energy consumption and carbon footprint of our homes has been approximately zero. Yes, there are a few net zero and passive houses about, but the overall impact of the movement has been negligible, and most energy efficiencies have been eaten up by increases in house size. Mechanical engineer Robert Bean thinks he knows why: We have been selling people something they don't want to pay for. He writes in the Seventh Wave:
Since 2004 it is likely hundreds of millions of dollars have been spent in North America promoting energy efficiency rather than focusing on the five senses that humans use to judge the built environment. So hold that thought and consider this…the highly acclaimed Rocky Mountain Institute recently stated: “Seventy percent of whole home performance customers cited comfort as a reason for their upgrade.”
He claims that consumers want comfort while professionals try to sell them energy efficiency, and they are not the same thing. He is not alone in this; I have explained why I dislike the Net Zero concept because you can have a crappy uncomfortable building that has solar panels on top. Elrond Burrell has written that The three most important things about passive houses are comfort, comfort and comfort. But Robert Bean takes it to a new level.
Robert looks at insulation, air leakage and windows, reframing them all in terms of comfort instead of energy efficiency. With insulation, for example:
Where an energy efficiency approach says adding insulation reduces energy consumption, the indoor climate approach says adding insulation results in higher mean radiant temperatures in winter and lower MRT’s [Mean Radiant Temperature] in summer. No occupant interviewed ever said they wanted to live in a meat locker or oven and if preventing that with insulation conserves energy all the better. The broader populace gets comfort. They generally don’t get u values, conduction, kilowatts and therms and thermal bridging even though the results are the same from an energy perspective.
Mean Radiant Temperature is a concept that is sometimes hard to understand, but it is Operative Temperature, which is MRT in combination with air temperature, not temperature alone, that determines comfort. (See Allison Bailes' terrific explanation with an equally terrific title Naked People Need Building Science) You can have your Nest thermostat tell the furnace to pump warm air all day but if you are next to a cold wall or window, with a low MRT, you are going to lose body heat to it no matter what the air temperature is. But it's complicated and people don't get it. And it is more than just words. Robert Bean:
Well, if you made it this far you likely “get it” or are arguing that this is semantics. But it isn’t. Only the comfort approach starts with the occupants senses in mind and this is the DNA for designing and constructing buildings in the first place. So here’s the thing…when you focus on comfort the light comes on in a eureka moment and people get twitter crazy.
He's right. Particularly now, when energy is cheap, people are not very interested in a big investment to save a few bucks over the next twenty years. But tell them that they will be more comfortable, they will breathe better air and will stay comfy when the power goes out, and it resonates. It's why I have become such a fan of the Passive House concept; even though they are designed around an energy consumption standard, the result is comfortable. It's also why I have come around to admire the Well Standard; they get comfort, nourishment, lighting and mindfulness in a way that more conventional standards do not. They get that we should be focusing on people, not buildings; that the real role of a building is to keep us healthy, happy, safe and comfortable. Energy is just an input, a variable; the fact that a comfortable building will use a lot less of it is a happy coincidence.
Here is a great little video that explains that what and how we feel has little to do with actual temperature.
Read Robert Bean's whole article here and visit his website, Healthy Heating. Robert notes that he set it up "to serve as an interpreter between the health and building sciences with a focus on thermal comfort, indoor air quality and the energy required to condition people and spaces." Sometimes I feel that I need an interpreter to understand it all, but it is the best resource I know.