Many of my home energy audit customers have asked, “How can we be more comfortable?” Here are some strategies…
Comfort is a function of how much heat enters an area versus how much heat leaves the area in a given time period. If more heat can enter the area than leaves it, then the heating system can attain the thermostat set point and you are probably comfortable. When it is colder outside (e.g., below zero) more heat leaves the area than when it is in the 40’s. In colder times a heating system might not be able to keep up and you will not be able to attain the thermostat set point and then you may be uncomfortable.
So, one short answer has always been: burn more fuel to get more heat. This is why so many heating systems are oversized. And while burning more fuel may work, it certainly is not the most efficient answer and it can be very costly.
An energy conservationist might answer the same question about comfort by saying, “Air seal and insulate the space better.” Now we are getting some where – less heat leaves the space, so less heat is needed on the in-between days and the existing heater will be able to keep up on the colder days. So like so many energy problems we face, the first effort should be to conserve energy – in this case air seal and insulate your home better.
But our focus is on big, older homes, and sometimes it is difficult to air seal and insulate them sufficiently to make them comfortable on very cold days. Or, as has been more the case the last few years and is certain to be the case in the future, you don’t want or can’t afford all the fuel needed to make the whole house comfortable, even when it is fairly well insulated and air sealed.
Now we need to start thinking inside the box. Comfort is a function of air temperature, air movement, wall temperature, humidity, how you are dressed, what you are doing, how old you are and even of what medications you may take. A lot of my customers are older and not as active as they once were. They certainly dress for winter with sweaters and extra socks, but still they are cold.
A very efficient and cost effective strategy is to heat just a portion of your home to a greater degree and allow the rest of the house to be cooler. Overall this uses a lot less fuel and while you are in the warmer area (perhaps most of your waking hours) you can be comfortable.
Many families close off the upstairs where just the bedrooms are. They restrict the heat by shutting registers or turning down the upstairs thermostat if their house is zoned this way. This can be quite effective. Isn’t it odd that we can comfortably camp in the Adirondacks on 40 degree nights but can’t be comfortable in our own bedroom when the temperature drops below 62 degrees? Another blanket, a hot rock or a dog should make for a comfortable night. Here I think it is just getting your head around the idea, not a limit of physics or the human body! Has anyone tried an insulated sleeping cap lately? Certainly 50 degrees should be comfortable sleeping!
To carry this approach further, it costs a lot less to heat 400 or 600 square feet than it does 3,000 or more. Perhaps you have a kitchen and sitting area where you do most of your daily tasks. If your computer and TV are in the same space you may be all set to implement this strategy. Now the heat to the bedrooms, front hall, dining room, living room, sewing room, guest room, storage room, etc. in this big old house can be turned down most of the time. We will just heat our active area, where we can do most of our household tasks, read, write, watch TV, visit with family and friends, prepare and eat meals in comfort and save 20%, 30%, 40% or more off our fuel bill.
There are a number of ways you can approach thermally separating and allocating heat to your active area. One of the easiest is to just close the door or two between this area and the rest of the house and use an existing wood or pellet stove, electric space heater (preferably for smaller areas, like a day time office), or if this space is already on a separate zone (lucky you), just adjust the thermostats.
Most aren’t quite this lucky and a little work will be required. As energy becomes more expensive, what we can do and should do to save energy and maintain comfort will increase. Now installing a door, or even building a partition or two can be reasonable measures. If you do build a wall, be sure to insulate it - this will help both with controlling heat and sound. You may have to be more creative. Think small to begin with – you can always make the active area bigger later, if necessary.
Once you have settled on an area to for the bulk of your daily activities, you need to heat it efficiently. If you have a boiler and radiators, maybe a little plumbing will allow for a separate zone in this area. Maybe it is as simple closing the registers and throwing a heavy carpet scrap over them. Maybe it makes sense to install a wood or pellet stove. Don’t use an unvented heater – propane, natural gas or kerosene – they can make you sick or worse!
You might want to try an electric space heater in your space just to see how it feels, but remember electric resistance heat is the most expensive form of heat available today. So, unless the space is very small, a more permanent alternative should be planned. On the other hand, a lot of people are cold because their feet are cold; maybe an electric foot-warmer will work for you. I once worked in an office where the floor was an uninsulated, slab-on-grade. A 44 watt foot-warmer made all the difference ($0.06 for an 8 hour day of comfort!).
Maybe you can use the sun? Maybe you need to add a window or cut a tree blocking the sun. If the space is small a little sun can make a big difference in both the temperature and the mood of the space. If you do add a south-facing window, be sure to get a low U-value (<0.25) and as high SHGC as you can (>0.40 if possible). The second number, the solar heat gain coefficient, is the portion of solar heat your window will let in. Perhaps you can add a solar heat collector beneath your window; these units collect heat when the sun is shinning and minimize heat loss the rest of the time.
A word of caution: Monitor your “outside” plumbing to be sure it doesn’t freeze. One homeowner drained the upstairs bathroom each winter, just to be sure. Also check your basement to be sure that with less use of the main heating system, pipes down there don’t freeze. Most houses won’t have a problem if the heat is reduced to 45 or 50 degrees, but until you monitor your weak spots you won’t know for sure. Also check again on cold nights, to be sure you are still OK. Yes, there is a little risk here, but if you are careful, make a few improvements to protect weak points, maybe even drain some of the lines, and monitor the situation until you are sure nothing will freeze you will be comfortable and save a lot of energy and money!
One last note: I know this strategy is not for everyone. But if there are just one or two people in your big, old house and it is impractical to heat the whole building, then the energy and cost savings, not to mention the added comfort, are well worth the time and effort to implement this strategy.
Dan Gibson is the Reporter and Chief Coordinator of Our Energy Independence Community (www.OEIC.us). Previously he performed home energy audits for five years in NYSERDA’s Home Performance program and new home ratings in the New York ENERGY STAR Home program. He is currently building a 100% Solar Home. He can be reached at DanG@OEIC.us