Introduction
In most areas of North America, periods of cold and wintery weather are common and can even characterize the late weeks of the autumn season. Even if these outbreaks are only harbingers of what is to come, they remind us that we should be preparing for the coming cold of winter. Our home is our refuge from the cold outdoors, its basic function to maintain a comfortable thermal environment for those living within. Comfort against the winter cold requires using some energy consumption. But energy consumption is expensive both to our bank account and to the environment. If we can reduce our level of energy consumption without sacrificing comfort, we will not only save ourselves money but also reduce our environmental impact.
What I will present in this article are a number of simple actions to cope comfortably with the cold season and, in the process, save some money on energy costs. For those interested in some of the science behind thermal comfort, a short primer can be found in the sidebar to this article.
Note that I will focus the discussion on houses. I cannot think of any problems which are not shared to some degree between houses and apartments. Apartments are basically a special case of a house where at least one side is shared with another apartment rather than the outside environment. I will also talk of personal comfort in the collective sense, referring to the comfort of all living within a home, individually and collectively.
Maximizing Personal Comfort While Reducing Energy Usage
I assume at the start that major winterizing projects for your home have already begun or are completed: e.g., caulking the outside of the building for air leaks, installation of storm windows and doors, proper wall insulation, and window glazing are major projects which go a long way in reducing heat loss from a building. I strongly suggest that an evaluation of energy usage and potential sources of heat loss be undertaken. Guides for energy conservation are available from your local energy utility, bookstore and public library. Utilities or local contractors can provide energy audits of your home, often at low cost. If you are new to your current home, I suggest keeping a notebook of any observations during the coming winter of energy losses, which cannot be easily and quickly remedied, for later attention.
Our goal is to increase personal indoor comfort during the cold season while at the same time reducing our overall energy consumption. Sure, we could always turn up the thermostat and heat the whole house, but that would not be the ecofrugal path. Therefore, the methods discussed here will generally be focussed toward small-scale actions to increase personal thermal comfort which are simple and inexpensive over the long run. Major home renovations may be in order, but they are for other discussions.
There are at least three areas where we can act to maximize comfort without increasing overall energy usage: building, room and personal. The following suggestions are not exhaustive; there is always room for new and innovative ideas. If none of the ideas are specifically applicable, they may spark the birth of an alternate solution.
The ideas presented may apply differently in homes heated by a centrally controlled heating system from those heated by individual room controls. In a central heating system, only one room contains a thermostat, and it tends to be placed in a large, main-usage room. Rooms in a central heating system, however, usually have some degree of control for reducing the amount of heat entering it, but generally cannot be given extra heat.
Conserving Building Heat
Our prime goal in conserving building heat is to minimize heat losses in order to reduce our energy requirements for heating while maintaining thermal comfort for the residents therein. Most methods for conserving building heat entail large projects best undertaken during the warm season: installing insulation and thermopane windows, patching potential sources of air infiltration, and planting protective vegetation to minimize wind speed close to the house. However, there are several annual tasks which should be undertaken to maintain building thermal integrity.
The main autumnal task for conserving building heat is annual building winterizing. This task includes installing storm windows and doors, checking the condition of exterior caulking, placing firewood in a spot protected from excessive moisture and cold, cleaning forced-air system furnaces, cleaning humidifiers and checking room heat ducts and radiators for obstructions to proper function. Yard maintenance may also help. Trim trees, shrubs and hedges which may prevent sunlight from entering rooms. This is more important in northern areas where this vegetation is not also used to reduce summer solar heating.
Set-back thermostats should be checked to ensure they conform to the current living schedule and the changing hours of daylight. I had our set-back thermostat set to drop the house temperature during the day when everyone was at school or work. The next year, the children came home later in the afternoon, and I could add an extra hour to the daytime set-back. The optimum settings may also change year to year or with the situation. I found that 20oC (68oF) day and 15oC (60oF) night temperatures were optimum temperatures for the family, but I had to raise them several degrees when my mother came to visit.
Conserving Room Heat
Once we have done all we can to assure we have minimized building heat loss and cold air infiltration, it is time to turn our attention to individual rooms. Look at each from the point of view of usage. Certain activities require different temperatures for maximum comfort. Bedrooms, if used only for sleeping, and kitchens generally may be kept at cooler temperatures than bathrooms and television or sitting rooms. Rooms only used for certain periods of the day or for certain occasions may be kept at lower temperatures when not in use.
Having determined the primary room usage and the optimum temperature for that use, we can adjust the room temperature to that level. If we have individual room heating, we can turn the local thermostat to the appropriate temperature and turn it down to a maintenance level for hours when the room is not in use. With heating controlled by a central thermostat, we have to work with the prime setting for the house. However, we can often still lower a room's temperature by adjusting the local heat entry port to restrict the movement of heated air or water into it, thus allowing heat to be available to other rooms.
Whenever air leaves a heated space, it takes thermal energy with it. The warm air is replaced by cold, exterior air which must be heated in order to maintain a comfortable temperature. Therefore, never open windows to cool a room except under unusual circumstances. Remember that when you open a window or door, the warm air that is escaping was likely warmed by energy you paid for. If you must open a window or door for ventilation or some other reason, isolate the room by closing all doors connecting to other rooms and turn down any thermostat located within the room.
If a room becomes overheated because of sunlight or oven use, consider the possibility of moving that air to another room using a fan or opening interior doors. If the room is large and the house is heated by a forced-air furnace, you can often turn on a fan in the furnace to distribute that air throughout the house without engaging the heating elements.
You should also consider consolidating activities into a few small rooms which are easier and cheaper to heat, especially during the coldest months and days. For example, a small and cosy room for reading, watching television and handicrafts can be easier and cheaper to keep in the comfort zone than large family or living rooms. If most family activities are done in a den or family room, consider reducing the temperature in the living room or closing it off when not in use. Unfortunately, it is often a large living room where the thermostat for central heating systems is located making the task slightly more difficult.
Rooms lose heat primarily through windows and doors, especially doors to the outside. They can also gain heat through windows and exterior doors during sunny periods. Windows and doors lose heat through conduction and radiation, and through convection if not properly sealed.
Room heat loss through windows by conduction, warm air loss, or cold air infiltration can be reduced by making sure that they seal properly when closed. If the window will not be opened during the cold season, consider sealing it with a plastic film sealed tightly around the frame. This eliminates cold air infiltration and isolates the window glass from the warm air in the room, thus reducing heat loss by conduction. Insulated shades or curtains can help reduce conductive heat loss by isolating the window pane from the room air, the tighter the covering, the greater the insulating effect.
Room heat is also lost from windows through radiation, but some may be gained during daylight hours if the window faces the sun. Radiative heat loss can be reduced by covering the window with a shade or curtains. If sunlight is used to supplement room heating, be sure to re-cover windows when the sun is no longer shining strongly through the window. This is very important because a window always radiates heat out and is a heating source only when the amount of heat radiation coming in exceeds that leaving. Cold window glass is a major factor in lowering a room's mean radiant temperature. Doors to the outside lose room heat mostly through conduction, warm air loss and infiltration of cold, outside air. If the door will not be used during the cold season, consider sealing it with a plastic sheet around the frame. If this is not possible, make sure that there is a good seal around the door to eliminate drafts. A door snake or door dog, a cloth or plastic "bean bag" which can be placed tightly against the foot of the door, will reduce cold air infiltration.
Differential heating in rooms of a home is simplest to maintain when the space is divided into small volumes. This is generally accomplished by the closing of doors between rooms. If there is a large space between the floor and the door foot, again consider using a door snake.
Following the fundamental laws of physics, warmer air rises above cooler air. Therefore, the warmest air in a room is usually near the ceiling and coolest air near the floor. This temperature differential can be reduced if the air is kept circulating in the room. Ceiling fans are a good way to keep up such a circulation, but even small fans, placed atop shelving or furniture and properly oriented, can mix the air sufficiently to reduce the temperature difference, thus warming the air near the floor.
If the interior surface of walls facing the elements become cold due to poor insulation or extreme outdoor cold, they will have a major impact on lowering the mean radiant temperature of the room. Thus, occupants of the room will lose body heat to these surfaces, and to compensate, the room temperature may have to be raised. Windows pose a similar situation, not only allowing great amounts of energy to escape directly, but also lowering the mean radiant temperature.
Furniture, such as wardrobes, bookcases, entertainment centres and hutches, cupboards and shelving can be placed against outside walls to reduce the contact of warm room air with the coolest walls. As well, such placement will increase the mean radiant temperature. This should be of minimal effect in a home with well-insulated walls, but can have a significant impact when placed against poorly insulated walls.
Enhancing Personal Comfort
The ideal room air temperature for comfort is a personal perception and may vary widely within a family and even with time and situation for an individual. Therefore, at whatever level we set the temperature, someone may be too warm or too cold. The solution to this dilemma is to achieve personal comfort through one or more of a variety of personal actions: altering clothing, intake of food or drink, changing level of physical activity, baths or showers, altering body position, using personal heating devices, blankets, afghans, etc., and family togetherness.
If we wish to be ecofrugal about our energy consumption, we can determine the minimal overall temperature at which we can keep the house, set back the thermostat to this level and enhance personal comfort through individual room control of temperature and personal means of heating or retaining body heat.
Think small scale. Remember it is always more efficient to maintain or increase the temperature of a small space than a large one. Rather than heat the whole home, heat yourself or reduce your loss of body heat.
Clothing: Wear sweatshirts and pants, sweaters, warm shirts and slacks, footwear, warm socks, and thermal booties, hats and gloves if necessary. Consider multiple layers of clothing.
A large percentage of body heat is lost through the head. A hat or hooded shirt can retain body heat. Cold feet and hands increase discomfort; therefore warm footwear and tucking hands into clothing, pockets or blankets, or the use of light gloves can go a long way in increasing full body comfort.
Food and Drink: Hot foods such as a hot bowl of soup or cup of beverage are always a good way to drive the chill away. Even the act of holding the cup or bowl can warm your hands enough to change your comfort level.
Physical Activity: Physical activity affects the body's metabolic rate and thus its thermal comfort. Physical movement can cause muscle activity to generate heat which warms the body and increase blood circulation to cold extremities. A couple dozen push-ups, or a few minutes of running in place or use of exercise equipment can get muscles and circulation going. Even better, get up and dance to a peppy tune on the radio or stereo or to the commercial jingle on the television.
If we take sleeping as a base metabolic rate, sitting and reading increases metabolism by about 50 percent, routine housework doubles the rate and moderate activities such as dancing and calisthenics can increase it fourfold. Approximately 80 percent of metabolic energy production goes to heating the body.
Baths and Showers: Hot baths and showers can, of course, also be used to warm us up. Do not be to hasty to drain that tub. The heating of water is the second greatest use of energy for most homes behind heating/cooling. Allow some of that heat to escape into the room and warm it. You have already paid for that heat, don't just throw it away!
If, before you have towelled off, you feel very chilled after leaving a bath or shower, it is likely not a indication of a low bathroom temperature but of very dry air. In most areas, the cold season is characterized by very dry indoor air conditions, especially with forced-air heating systems. The moisture evaporated from a tub of standing water can help relieve the situation. For showers, plug the tub and do not let the water drain immediately. If you fear overflowing the tub during the shower, then you may want to reconsider your water-use habits.
Altering Body Position: Sometimes, you can increase your thermal comfort by sitting with your feet off the floor — remember that the coldest air in the room is likely at floor level. The alteration of body position I like best is to move close to and snuggle up with a loved one. Sharing body heat is enhanced by the positive feelings of closeness.
Use of Blankets, Afghans and Personal Heating Devices: Rolling up in a blanket or laying an afghan over your legs or shoulders can usually chase away the chill. Keep a number of them in your most frequently used rooms for enhancing your comfort. Personal heating devices such as a hot pad or hot water bottle may also be used for warming the body.
Family Togetherness: Family togetherness can go a long way in enhancing comfort during the cold season, apart from the inner warmth of a loving unit. Each of us loses heat from our bodies to the environment. If we are alone in a room, we lose that heat to the air, furniture and walls, some of which radiates back to us. If we share the room with others, however, we radiate some of our body heat to them and receive some of their radiant energy. That is, we all contribute to increasing the mean radiant temperature of the room. And, the more bodies, the warmer. In a small room, body heat often can be a significant source for room heating.
Use the after-dinner hours to spend a few hours together in recreation or other activities in a common room. In past days, it was common to spend the evening hours around the kitchen table, using the heat gained from preparation of dinner on a wood or coal stove. Too often these days we all scatter to different parts of the house, requiring the heating of large areas and wasting the heat produced in the kitchen during meal preparation.
Putting It All Together
Keeping comfortable at home during the cold season is a continual struggle for all residents of northern North America. While we can always "turn up the thermostat" to ride out the colder periods, such actions are costly to our pocketbook as well as the environment. However, with a little thought and ingenuity, we can attain a comfort level with minimal costs to our finances and environmental impact. We can even reduce our "normal" heating costs by turning down the thermostat and applying local measures for heating and retaining heat to maintain us in the comfort zone.
Too often we have been conditioned to accepting the large scale view to home heating. That is, we use external energy sources to heat our full home to a comfort level for a lightly dressed person (i.e., short-sleeved shirt and slacks or skirt). If we change our perspective to look at home heating from the small scale view — working upward from a point of personal comfort — we can affect major energy savings without sacrificing comfort.
So, find that cozy spot in your home, sit back, grab that blanket, snuggle up to a loved one and laugh at that howling, frigid wind blowing through the trees.