There are four common types of heating units:
- A furnace provides heat through a forced air distribution system.
- A boiler provides heat through a hydronic distribution system. (Hydronic systems are also referred to as hot water systems.)
- A space heater supplies heat directly to the room where it is located.
- A heat pump extracts heat from the air, ground or water outside the house and usually delivers it through a forced air distribution system.
Most heating systems need air for combustion. Furnaces, boilers and space heaters that burn fuels need a supply of air to be able to burn properly, and a vent to the outdoors so that combustion gases can escape from the house. Electric heaters do not need to be vented.
Combustion is a two-step process: Air in, and gases out
In the past, there was usually plenty of air leaking into a house to keep the furnace, boiler or stove burning well. Modern homes, however, are better sealed and use controlled ventilation - rather than uncontrolled leakage - to provide greater comfort and energy efficiency. Vents that supply air for heating units should never be blocked. It is important to ensure that there is an adequate supply of combustion air available, even when other air exhausting equipment is in use.
Venting used to be done through a chimney. Today, however, many models of natural gas, oil and propane equipment can be vented by pipe directly through the wall, which greatly simplifies installation. Remember that combustion gases cannot escape from your home unless you provide air to replace them. That's why venting problems can often be traced to air supply problems.
The indoor temperature is automatically controlled by a thermostat. Two important considerations are location and type. Central systems are normally controlled by a single thermostat. To achieve proper temperature control, the thermostat must be located in an area where it will sense the "average" indoor temperature. Locations exposed to localized temperature extremes (outside walls, drafts, sunlight, hot ducts or pipes, etc.) should be avoided.
Different types of thermostats are available. Basic types maintain a fixed indoor temperature. However, you can reduce your heating costs by installing a set-back thermostat which can be programmed to automatically lower the temperature when no one is home or everyone is in bed, and then warm up the house before you get home or wake up. Savings will vary, but a set-back of 3ºC for eight hours daily could reduce your heating costs by about five per cent.
Where space heaters are used, each unit will likely be individually controlled by its own thermostat - which is usually the basic type. This allows you to keep unused areas at a lower temperature than those areas you do use.
A Word About... Air Quality
Air pollution can sometimes be worse inside your home than it is outside. As you increase the air-tightness of your home, you must also keep air quality in mind.
Recognize sources of pollution in your home
Air-borne pollutants are either biological (mould, dust mites, pollen, animal dander) or originate from other sources (gases or chemical particles released by furnishings, carpets, construction materials, un-vented appliances, renovation activities including dust from lead paint, poorly-maintained heating systems, humidifiers and dehumidifiers).
Your heating system
All heating systems and other equipment that burn fuel give off combustion gases. Occasionally, a portion of these gases might "spill" into the home instead of exhausting to the outdoors. If you suspect a problem, ask your fuel or equipment supplier to check for combustion spillage and make any recommendations necessary, such as installing a combustion air supply or upgrading or replacing equipment. You should have a working carbon monoxide detector. They are now mandatory in many situations.
Wet firewood brought into the home to dry can both introduce and support mould growth. Wood should be stored outside until needed.
Is your home well ventilated?
If you are planning to make your home more air-tight, be sure to check into the need for improved ventilation. A mechanical ventilation system is a must for any well-sealed home. A heat recovery ventilator goes a step further and provides more energy-efficient ventilation by reducing heat loss as outdoor air replaces indoor air. See the Home Air Quality listing for places to obtain more information.
© 2005 Queen's Printer for Ontario
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