Thermostats for Efficiency and Comfort

What a thermostat does

Regardless of the type of heating system you have in your home, the thermostat plays an important
role in ensuring your home is comfortable. Your thermostat determines when your heat comes on
and off, what temperature your home will be heated to, and can help reduce your heating bills.
Essentially, the thermostat is the “brains” behind your heating system.

Types of thermostats

There are two basic types of thermostats line- and low-voltage with a number of options for each type.

• Line-voltage thermostats: Line-voltage thermostats are used to control unitary heating systems, such as baseboard and radiant systems. The thermostats are installed in-line (in series) with the heater, usually at 240 volts. The full current going to the heater also goes through the
  thermostat, causing it to heat up when the heater is on. This may cause the thermostat to sense its own heat and shut off before the room is comfortable.
  
• Low-voltage thermostats: Low-voltage thermostats are used with gas, oil and electric central heating systems, zone valves in hot water heating systems, and electric unitary systems
  where better control is required. Low-voltage thermostats operate at 25 to 35 volts, rather than
  240 volts. They are more responsive than linevoltage, provide more accurate control and are
  more adaptable to programmable controls.

Thermostat options

Whether your thermostat is line-voltage or low-voltage, there are three general options to choose from.

• Mechanical: Mechanical thermostats are inexpensive and easy to install. Thermostats with mechanical operators (i.e. not electronic) have either a bi-metallic strip or a vapor-filled bellows to react to temperature change. Some are relatively slow to respond, (particularly the inexpensive units with bi-metallic strips), which may result in large temperature swings above and below the thermostat set point.
  
  
• Electronic: These thermostats use electronic rather than mechanical components to sense temperature and control the heating system. They are available in both line-voltage and lowvoltage models. They provide accurate temperature control and react more quickly to temperature changes. Many electronic thermostats have added features such as automatic setback and programmability. This makes them more expensive than mechanical models.
  
  
  
  
• Programmable: Programmable thermostats automatically adjust the temperature at pre-set times. When you pre-set your temperatures to correspond to your daily activities you will save energy because the thermostat can be pre-set to automatically turn down the heat at night or when the home is empty and turn up the heat when you are home. Models range from simple clock-like thermostats that provide day and night temperature settings, to electronic models that let you set different day-of-week and time-of-day temperatures.
  
  If you have a unitary heating system, such as baseboard heaters, the Canadian Electrical Code requires a thermostat be placed in each room. A programmable thermostat in every room would be expensive. Instead, install programmable thermostats only in large rooms that have a great deal of activity, like a living room, family room, or children’s play room. This way it can be programmed to be on during active times and turned down at times when the room is empty.
  
• Special-purpose thermostats
  Special-purpose thermostats have features designed to work with specific types of equipment. For example, two-stage thermostats are used for hybrid heating systems using two fuels, such as electricity and oil, to turn on the backup heating system when the primary system cannot cope with the demand for heat. Heat/cool thermostats are used for homes with summer air conditioning.
  

Selecting a thermostat

When choosing a thermostat, look for a Power Smartcertified model. Power Smart thermostats are responsive and accurate, and they keep the indoor temperature consistent despite large fluctuations outside. There are Power Smart thermostats for all types of heating systems.

Thermostat location

Mount thermostats about 1.5 metres (5 feet) above the floor, centrally located on an inside wall. Never install thermostats in areas subject to drafts, direct sunlight or sources of heat such as warm air registers, refrigerators, ranges or other appliances. All of these factors can inadvertently affect the
thermostat by causing it to read the temperature incorrectly and not respond to the actual room temperature.

Recommended thermostat settings

These are suggested thermostat settings that provide comfort and avoid overheating. Thermostats in rarely-used rooms can be set lower than those in major living areas.

Setting the thermostat back from 21°C to 18°C degrees at night, can result in energy savings from five to nine per cent, depending on where you live.