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December 2, 2007
Responding to your thermostat comments...
All right, there has been a great response to the post asking what you all thought about thermostats. Thanks to everyone who contributed. There is a lot of good information in your comments. It's funny how we use the term thermostat, like it's an easily defined product that simply controls temperature. However, the variation in experiences indicates it's not so simple. The comments show that it is hard to talk about one component without bringing other components of the house into the conversation.
It's clear that the thermostat is not solely responsible for the thermal comfort in the house; all sorts of other things matter. This is a challenge.There are a lot of factors involved in keeping the people in a house comfortable and not the least is that comfort itself is not a constant from person to person, nor even for one person at all times. Here is a summary of your comments and some further discussion of some of the topics. This is why building scientists and design teams look at the whole house as a system and try to balance all aspects of the design and expected use in a house so the final design has the best opportunity to provide a comprehensive package of performance, utility, and aesthetics.
By my unscientific accounting, it looks like more than half of the respondents are using programmable thermostats, although half of those folks find them lacking in some way. That's an unfortunate acceptance level for a technology that is marketed as having the ability to save a lot of energy. There are a lot of reasons why the programming function fails some users. It's too complicated for some. It's too simplistic and inflexible for others. Houses are built differently and there are many types of heating and cooling systems that can be in the house. Every situation is unique and an educated choice really needs to be made to find the best controls for the heating and/or cooling system. Used correctly, they do offer a lot to many people.
As an example, my mother would be ill-served by a programmable thermostat. Her schedule changes throughout the week, and she simply turns the thermostat up or down as she leaves or returns. She has a forced air furnace and an air conditioner. Her house has a quick response time when recovering from setback (or set up in cooling). On the other hand, my house has no cooling, and heating is accomplished by cast-iron radiators heated by a boiler. On cold winter days, it takes my system about 2 hours to recover from the 59F setback temperature so it is 67F when we get up at 6 AM. Similarly, my wife and I are out of the house during the daytime hours, so it makes sense to drop the heating setpoint when we leave for work and have it programmed to have the house back up to temperature around the time we return. The programming feature is very important for us and surely saves a lot of money on our winter heating bills. When our schedules change, the programming is easy enough for us to alter or override. I love Laura's idea of having a "tomorrow is a holiday" button so the thermostat knows to use the weekend programming on days I'm working from home.
Several folks commented that they would like to have a thermostat with a larger, backlit display. As someone pointed out, there are large text models on the market, but it's not necessarily what's in your house already or easy to find at local retail stores. Thermostat location height on the wall is also tied to this. I agree that, frequently, the thermostat is mounted below eye level (at least for me). I suppose I don't mind crouching a little because the alternative would be that a shorter person wouldn't be able to see it at all if it were mounted higher. Maybe someone who does installation can comment, but I also think that the lower position does a better job of measuring the temperature nearer the middle of your body. Most of the time, the floor will be colder than the air near the ceiling. This stratification plays into comfort and the system controls. A single point measurement is not really ideal for characterizing the temperature throughout the whole house (or zone), especially when there are multiple floors, long distances to certain areas, or high load areas like sunrooms or exercise rooms. It becomes the responsibility of the heating/cooling contractor and whoever designed the system to balance the airflows to provide adequate distribution of conditioned air and to make sure the system is designed correctly. Multiple temperature measurement locations may be better in some situations (like in a zoned system).
Thermostat mounting is also an art. The contractor's unfortunate responsibility is to find a good location that is accessible and more or less representative of the average temperature of the space. It cannot be unduly affected by direct sunlight, drafts, internal loads, etc. Unfortunate to the aesthetics of many, this location may end up in the middle of a wall, making decoration difficult. While some may be more pleasant to look at than others, most thermostats are relatively neutral in appearance. Todd mentioned one thermostat as an example of manufacturers addressing the aesthetics. It has a modern, clean design that sticks out less from the wall than many we've seen in the past. There are many choices in appearance as well as functionality, however there are limits to what you can find on the self local to you or available through local HVAC contractors.
So, in short, it seems that some are finding thermostats to be either too complicated or too simple, bulky and ugly, ineffective as a gauge of the whole-house's thermal comfort, and usually located in less than ideal locations. As I mentioned earlier, this is an unscientific study with a lot of bias, I would assume. I know there are a whole host of people out there that are happy as clams with their thermostats, and who set them and forget about them.
One thing I was hoping to get some insight into was home automation systems. There are some slick systems out there that combine the controls for several systems in the house into one interface (sometimes with multiple locations). For example, an architect I know built a house for himself with a home automation system that combines temperature control for the various zones in the house with the security system, lighting, and audio. He can also 'log into' his house from afar and make sure the lights are off or tell the furnace he won't be home from work until 8 PM and to have the house warm or cool for him then instead of his normal 6 PM. I think this is an interesting topic that I don't have the space to discuss further here and now. Please leave comments if you have any experience with home automation systems. I'll put together some information as well, and we can do another round in a week or so.
Posted by Eric Helton at 9:58 PM | Comments (1) | TrackBack
