What I have learned about climate control in a dwelling falls into three categories: heating, cooling, and humidity control.
Heating keeps a house warm during cold weather. A few old houses may still be heated by fireplaces, wood stoves, or propane heaters like the Warm Morning heater. Other houses may have a furnace that takes advantage of passive heat flow. In these furnaces, a tube goes up from the furnace (in the basement) to each register in the house. The warm air created in the furnace naturally drifts upward.
By far the three most common kinds of heating at this time, though, are radiators, baseboard heaters, and forced-air furnaces.
A radiator is a metal device filled with water and connected to a boiler. When you turn the heat on the boiler heats the water and the hot water circulates through the radiator, which then radiates heat into the room. Old radiators are bulky. New radiators have low profiles and in new bathrooms, are often replaced by heated towel racks tied into the boiler, which sounds like a nice luxury. The drawbacks to radiators are that you need to keep them away from furnishings or the heat will affect the furniture over time (and they will radiate less efficiently), that they can get air in the water lines which creates a noisy creaking sometimes called “air hammer”, that once water has gotten in the lines the only way to fix the problem is to drain the whole system and fill it up again, which is an involved process that many landlords are reluctant to undergo just to remove a noise problem for their tenants, and that radiators do not circulate air inside the house. Radiators are often old installations in buildings and not necessarily tied in to a thermostat; many people find that even those that are, are almost impossible to control. I lived with radiators in a college dormitory and the only way to be comfortable when the heat was turned on was to keep a window open too.
Baseboard heaters are electric heating units installed along the baseboards of a room. They were more common in the middle of the twentieth century than they are now, though there are places where they are still common in new houses. Like radiators they provide radiant heat that is in theory silent–though older metal units often creak as they heat up and cool down (like a forced-air furnace, baseboard heaters are tied to a thermostat and will heat up and cool down intermittently). Also like radiators they need to be kept away from furnishings, and they do not circulate air inside a house.
Forced-air furnaces are the most common kind of heat where I live. In this system a gas or electric furnace is tied to a thermostat, and will periodically fire up, heat and blow air through ductwork and out of registers in the rooms, and turn itself off when the house has warmed up a degree or two. Other than keeping registers uncovered, you do not need to worry about their effect on furnishings. They circulate air inside a house, helping to keep humidity levels steady throughout the house. These furnaces are always noisy while they are turned on, so having a furnace tucked away in a basement or garage instead of, say, in a hallway closet, is an advantage. Forced air furnaces come in a range of efficiencies, with more efficient furnaces costing less to use. The drawback of more efficient furnaces is that they have more parts, and more parts means they are more likely to break. If you have a high-efficiency furnace you are going to wish you had access to someone who knows a few basics about how to twiddle their parts to keep them going–or you will learn yourself. Forced air furnaces all have air filters somewhere inside them. These filters take dust and pollen out of the air before blowing it around your house. It is extremely important to keep these filters clean; as Mike Holmes says, they are the lungs of your house, and if the house’s lungs don’t clean the air, yours will.
There are a few variations on forced-air heating that don’t use a gas or electric furnace to generate hot air. One is a heat pump and another is geothermal heating. I know very little about them.
Cooling falls mostly under the umbrella of air conditioning. There are three types of air conditioners I am familiar with. The first is the window air conditioner, which fits into a sash window or a special cutout in the wall and provides enough cool air for one room. These are usually noisy and desirable only when installed air conditioning isn’t available.
The second kind is the one I am most familiar with, in which a large air conditioner sits somewhere outside the house and pumps cold air through the same ducts and registers that the forced-air furnace uses. It usually uses the same thermostat the heating uses. The large air conditioner is unsightly and is usually hidden behind the house or a shrubbery. You can’t really service it yourself if there is a problem; you have to call a professional. This kind of air conditioning, just like forced air heat, requires that ducts of a certain size be run through the walls and floors of the house. Houses with plaster-and-lathe walls often cannot accommodate the ducts.
The third kind is popular in the Caribbean. It consists of small permanent wall units that provide enough cold air for one room.
There are other strategies for cooling your house: shade trees that protect the house from the sun, awnings that stop the sun from shining into windows and doors, windows open in the cool nighttime and closed in the heat of the day, and an attic fan that blows hot air out of the attic are all worth pursuing.
Lastly and most often neglected is humidity control. A dehumidifier is mostly useful in damp basements and rooms that have been recently flooded. For whole-house dehumidification, forced air heating or cooling are effective–so effective that many forced air units include a built-in humidifier to put some moisture back in the air. Having a whole-house humidifier makes the cold months much more comfortable, as humidified air minimizes winter problems such as dry skin, static electricity buildup, and the discomfort of head colds. If your furnace doesn’t have a humidifier, you can buy small units that humidify a single room. There are many kinds available, some that create hot steam and some that create cool mist, and you should do your own research to decide which you like best. I seem to be in the minority in preferring hot steam humidifiers. I like them because unlike every other kind, they do not have a filter that needs to be regularly cleaned and replaced lest it begin to grow mold and spew mold spores into the air. The drawback of a hot steam humidifier is that a small child may be burned by the steam jet, and the steam itself can sometimes irritate a person who is sick with a cough–a problem that can be fixed by pointing the steam jet away from, instead of towards, the sick person.
And there you have it; a very dry entry in my list of 100 Things About Housekeeping. Hang in there folks, we have a couple more dry topics to cover before we move on to fun stuff like bed linens and pantries…