Variable Speed

ECM 2.3 variable-speed motor technology can be compared to using a dimmer switch in lighting applications, meaning it is highly variable, making its precise performance ideal for a variety of advanced applications. Most manufacturers typically position an ECM 2.3 motor as a premium product offering and use the motors in furnaces, air handlers, condensing units and packaged products. The popularity of the ECM 2.3 motor can be attributed to its performance, flexibility and reliability.

(Note: There are several other ECM motor designs on the market. Some of these models are identified as ECM 2.5 or ECM 3.0 and include additional features that allow for more sophisticated programming options specifically intended for equipment that utilizes communicating control systems (also known as four-wire systems). In any case, the information that follows generally applies to all three ECM motor types.)
Unlike conventional PSC motors, which are designed to operate at one speed, ECM 2.3 variable-speed motors can run over a wide range of speeds. This is critical because blowers need to be flexible in order to deliver the airflow required by a multitude of system designs. ECM 2.3 motor technology provides the ability to program and deliver constant airflow over a wide range of ESP, typically up to 1.0 inches water column. Beyond programmability and efficiency, ECM 2.3 motors offer many other advantages that enhance consumer comfort. These motors are the quietest of the three motor types because they have the ability to ramp up and down slowly, making them ideal for applications where noise is a concern.

Variable-speed motors are also the best choice for constant fan or constant filtering applications because the motor will only run at about one-third of its designed speed, using less power than a 100-watt light bulb and resulting in both noise reduction and energy savings that the consumer will appreciate. The indoor environment will also benefit from better air stratification, ensuring more consistent and precise temperatures.

X13 Motor - Constant Torque

Constant torque motor technology is quickly becoming a popular motor technology. As a matter of fact, it may totally replace PSC motors in the near future as government actions and regulations continue to mandate increased efficiencies. Most manufacturers typically position constant torque motors as a mid-tier product offering and use the motors in furnaces, air handlers and packaged products. The popularity of the constant torque motor can be attributed to its performance and cost. For comparison’s sake, constant torque motors are basically upgraded, next-generation PSC motors. What differentiates constant torque motors from PSC motors is their ability to deliver constant torque (i.e., rotational force or power output down a shaft). In other words, if the ESP changes, then the motor program will maintain the amount of torque for which it was programmed (this is not the same as constant airflow).

PSC Motor

PSC single-speed motor technology has been the standard in the industry for many years and represents the highest installed base. PSC motors are typically positioned by most manufacturers as a standard product offering and are used in furnaces, air handlers, condensing units and packaged products. The popularity of the PSC motor can be attributed to its simplicity, reliability, low cost and flexibility. Because of the motor’s design, there are some disadvantages inherent in PSC motors. For example, PSC motors are significantly less efficient than constant torque or ECM 2.3 motors because they consume more watts, making them more difficult for a manufacturer to apply to a high-SEER system design. On average, PSC motors will use approximately 552 watts in cooling mode and 515 watts in continuous fan mode. Therefore, they are not ideal for continuous fan operation because they run close to full speed when applied in this manner, using more energy than this function really requires. (As a comparison, imagine the power consumed by five 100-watt light bulbs lit all day long). This also makes them less attractive for continuous filtration applications. Additionally, since PSC motors are not programmable and their motor speed cannot be easily varied, it is more difficult to apply the motors to two-stage or advanced systems.

PSC motors are also the least quiet of the three motor technologies. In addition, PSC motors do not offer customized airflow patterns, which are often critical in designs intended to manage humidity. Consistent air stratification and temperatures are also harder to obtain.



Modulating furnaces run in very precise increments. Some models can run at 40% capacity and increase by .5% if the thermostat calls for it. Because they can manage temperature so precisely in your house, they usually run continuously at a very low setting. The temperature in every room of the house remains consistent because of this continuous operation. The air isn’t blasting in then settling, then blasting. It’s constantly flowing. Modulating furnaces can achieve up to 98% efficiency, meaning 98% of the fuel that goes into the system returns as heat. But, being the most efficient and highest performing type of furnace also means they’re the most expensive.

Two Stage

The burner in a two stage furnace can run at two different levels. Different burners are programmed differently. But as an example, the burner may be programmed to run at two stages, 60% and 100% capacity. A two stage furnace is quieter and generates more even heat through the house. The longer, slower heating cycle eliminates the kind of rapid warming that many people find uncomfortable from a single stage furnace. The longer cycle also provides better air filtration, because the air cycles through the furnace air filter more times in a day. Air quality is significantly improved in the house if your two stage furnace has a humidifier. Two stage furnaces give buyers the best balance between cost and value. They are more expensive to purchase initially than a single stage, but run more quietly and efficiently.

Single Stage

A single stage furnace has two settings. The thermostat in the house calls for heat, so the furnace comes on. Full power. It will run at full capacity until the thermostat is satisfied, then shut itself off. This is the cycle, so you get somewhat uneven heat throughout the house. The furnace hits you with blasts of warm air that give you temporary comfort, but doesn’t do a great job of maintaining that comfort. In that way, a single stage furnace is not very energy efficient. But it is the most affordable option to purchase.



The AFUE is the most widely used measure of a boiler or furnace's heating efficiency. It measures the amount of heat actually delivered to your house compared to the amount of fuel that you must supply to the furnace. Thus, a furnace that has an 80% AFUE rating converts 80% of the fuel that you supply to heat -- the other 20% is lost out of the chimney. Note that the AFUE refers only to the unit's fuel efficiency (i.e. natural gas, propane of heating oil), not its electricity usage.


The SEER measures air conditioning and heat pump cooling efficiency, which is calculated by the cooling output for a typical cooling season divided by the total electric energy input during the same time frame. A SEER rating is a maximum efficiency rating, similar to the miles per gallon for your car. Your car might get 28 miles per gallon on the highway, but if you’re stuck in city traffic it could be lower. If your air conditioner is 21 SEER, that’s its maximum efficiency. A higher SEER rating means greater energy efficiency. The minimum standard SEER is 13 for air conditioners. Most modern air conditioners have a SEER that ranges from 13 to 21. It’s important to remember the efficiency of your system can also depend on the size of your home your current ductwork and other variables.


Air Source Heat Pumps, often used in moderate climates to heat and cool a home, are rated by a Heating and Seasonal Performance Factor (HSPF). Heat Pumps use the difference between outdoor and indoor air temperatures to cool and heat your home much like standard air conditioners do. The difference is that Heat Pumps can cycle in both directions and can therefore provide cooling in the summer months and heating in the winter. High efficiency Heat Pumps have a higher Heating and Seasonal Performance Factor (HSPF) and use less energy than conventional models.



The standard air conditioning control system uses relay logic or an electronic representation of relay logic. Things are either off or on. The controls work something like a light switch – when the switch is on the light operates, when it is off the light is off. Thermostats are basically switches that are controlled by temperature. A communicating control system is more like a computer network. The system components communicate over a serial network. Each part has its own unique electronic signature or address, allowing the controller to recognize all the parts and coordinate their operation. Further, communication is not just one way. Communication between components allows them to know what the other components are doing and adjust accordingly. For example, Rheem's EcoNet control knows what the blower CFM is and what the duct pressure is. Better yet, it can report this to the service technician. The system airflow can be ramped up or down to match system capacity. Staged furnaces, air conditioners, and heat pumps give the system the ability to modulate system capacity and airflow as the house load requires, improving efficiency and reducing energy use.


The standard air conditioning control system uses relay logic or an electronic representation of relay logic. Things are either off or on. The controls work something like a light switch – when the switch is on the light operates, when it is off the light is off. Thermostats are basically switches that are controlled by temperature. The thermostat closes a set of contacts to complete a circuit to a relay coil, the relay coil then closes the relay contacts to complete a circuit to a motor. When the thermostat is satisfied its contacts open, breaking the circuit to the relay coil. The relay opens its contacts, breaking the circuit to the motor. Everything works based on the presence or absence of control voltage. One advantage of this system is that it is easy to understand, and it has been the basis for HVAC/R controls for many years. However, this control system needs a separate control wire for each function. Some split system heat pumps require 12 control wires running between the indoor and outdoor section. Even with twelve wires, the range of control is still somewhat limited.



A communicating thermostat communicates to a communicating furnace or air conditioner. Almost all of these thermostats are designed by the furnace manufacturer to work with their specific equipment, this means that one brand's communicating themostat will not work with another brand's equipment. By using a communicating thermostat with the appropriate equipment the homeowner gains several benefits from the two-way communication. The thermostat can be used to fine-tune settings like blower speed at installation time and during operation. An example of this would be Rheem's dehumidification setting which lowers the blower speed during times of high humidity to maximize dehumification and ultimately comfort. Because the furnace can communicate with the thermostat, the furnace can relay messages to the homeowner or service technician of operation issues. Issues like overheating caused by a plugged filter will be displayed on the thermostat screen where as a furnace connected to a non-communicating thermostat would continually overheat until detected by a service technician. Most communicating controls also offer all the same smart features and typical "smart" thermostats. This includes Wi-Fi connectivity, voice control, phone control and alerts sent to your phone.


Smart thermostats are the latest trend in home heating. A smart thermostat can switch your heating on or off remotely via the internet - so you can use your smart phone to turn your heating on when you're on your way back from a weekend away, or off when you pop out unexpectedly. Many of these programmable digital heating systems show you how much heating you’re using. Some smart thermostats also monitor your usage and learn your routine. There are several brands of smart heating thermostats on the market, and each works in a slightly different way. Heating represents the biggest portion of most domestic energy bills - especially during the winter months. As smart thermostats are connected to the internet over your wi-fi, you can use your smart phone to control your heating even when you're not at home or if you can't be bothered to get up from the sofa to turn the thermostat down. As well as being able to use your phone or computer to turn your heating on and off, you can program a smart thermostat - just as you would a traditional thermostat. Except instead of having to go to your actual thermostat and work out what the buttons do, you can use your phone or computer to program it. Some smart thermostats can control themselves by learning your routine or tracking you via GPS, switching on your heating when you're near home.


The biggest benefit programmable thermostats offer is the cost savings. Energy bills continue to rise in all parts of the world, and the best way to combat this is to try to reduce your energy usage. With programmable thermostats, you can adjust the temperature to the exact point of your own personal comfort. For every degree you raise or lower the temperature in your home during the heat of the summer or the cold of winter, you can save up to 2 percent on your utility bill. You don’t have to keep your air conditioning or heat on high while you’re away from home. You can create a schedule that follows your family’s routine, and keeps the temperature cool or warm while you’re there, but eases up on the energy usage when you’re not home.


Heat Loss

No matter what you do, when it is 68°F inside a house and 0°F outside, the cold will suck the heat out of the house. It will pull at a certain rate through the exposed walls and ceilings, through the windows and floors. This is known as heat transfer. The cold air is also trying to sneak into the building through every little crack in every nook and cranny. This is known as infiltration. The home’s heat, on the other hand, is trying to escape through every nook and cranny. This is known as exhalation. It’s as if the house was breathing — breathing both air and temperature in and out. The total of all this leaking and losing at a specific low temperature for your region, is known as the heat loss. This total will be calculated in Btu per hour (Btuh), and the heating system will need to produce and distribute this same amount of Btuh to maintain a 68°F room temperature.

Heat Gain

The refrigeration cycle takes advantage of the relationships between pressure, temperature, and volume, in such a way that heat is collected inside and released outside. It uses a condenser, a compressor, and an evaporator to accomplish this task. The condenser and compressor are located outside of the house, while the evaporator is located inside the air distribution system. The quantity of heat that needs to be removed to maintain indoor comfort, on a specific warm day for your region, is known as the heat gain for your structure. A building gains heat from actual outdoor temperature and humidity levels. It gains heat from the people inside of it, from the lights, computers, copiers, dishwashers, ovens, etc. (Many contractors distribute an extra 1,500 Btu of cooling to the kitchen to offset the heat given off by the appliances, and an extra 400 Btu to various rooms for occupants.) But mostly it gains heat from its exposure to sunlight, from solar radiation. The hot sun beats down on the walls and the roof, the sunlight pours through the windows and warming the floors it lands on. The sum of all of this heat accumulation is known as the of the building.


When your furnace is too big, it will blast your home with too much conditioned air at one time. This can make your rooms feel too warm when your furnace is operating and lead to major temperature swings in your home. In addition, the rooms that are far away from your furnace will likely not receive enough warm air because the area around your thermostat will heat up too quickly and your furnace will shut down before every room is properly heated. Your furnace will short cycle. When a furnace is too powerful for the home it’s installed in, it will go through very quick heating cycles because your home will heat up too quickly. This puts your furnace through a whole lot of wear and tear, which will dramatically increase the likelihood of your system breaking down. Your heating bills will expensive. Your furnace consumes the most amount of energy when it is starting and heating up. If your system is oversized and short cycling as described above, it will spend much more time in “startup mode,” which will force it to consume more energy and lead to high heating bills. Your system won’t last as long. When you consider the amount of excess wear-and-tear that an oversized furnace goes through, it shouldn’t be surprising to learn that oversized furnaces do not last nearly as long as properly-sized systems.


The most common (and in many cases only) sign that your furnace is undersized is that the device simply doesn’t maintain the temperature in your home properly. This means that when turned on to full and left for a few hours, your furnace doesn’t heat your home to the thermostat setting. This can be due to an improper load calculation or a load calculation that wasn’t taken at all. The perfectly sized furnace will heat your home evenly on the coldest day your area is likely to have. So, undersizing should be pretty evident – if it doesn’t heat your home evenly and it’s not exceptionally cold outside, you might not have enough BTUs under the hood.

Design Temperatures

When sizing an HVAC system the outdoor temperature used to determine the typical coldest & hottest day is called the "design temperature." In the case of winter, this design temperature will be the coldest outdoor temperature expected during 99% of the hours during the year. This may result in rare harsh weather situations where a properly sized furnace may struggle to maintain indoor temperature. Increasing the furnace size to accomodate these 1% temperatures may seem ideal to some but the this results in the effects of oversizing during remaining 99% of the year. The summer design temperature is similar to the winter temperature in that it is the hottest temperature expected during 99% of the year's hours. Oversizing of air conditioners is especially detrimental as oversized air conditioners do not dehumidify properly and are for more likely to ice up. Design temperatures for Chilliwack according to TECA (Thermal Environmental Comfort Association) is: Winter: 10°F / -12°C Summer: 88°F / 31°C

Boiler Type


Combi boilers usually have two independent heat exchangers; one of which carries a pipe through to the radiators, while the other carries a similar pipe through to the hot water supply. When you turn a hot tap on, your boiler fires up to heat water and a valve is opened to send the water out through a network of pipes. A combi boiler will usually need to pause from heating the central heating water for your radiators while it’s heating the hot water for your tap, because they often can’t supply enough heat to supply to both at the same time. For this reason, you might hear your boiler switching on and off when you run a hot water tap even if they’re already lit to power the central heating.

  • Combi boilers are highly energy efficient, most manufactured with an efficiency rating of 90% or better
  • You could save money on installation compared to other boiler types, since no tank is needed therefore there’s less pipe work and a shorter installation time
  • Their compact size means they’re a great space saver; some combi boilers are even designed small enough to fit inside a standard kitchen cupboard
  • Water is heated on demand, so there’s no waiting for a tank of water to heat up to run a bath or shower


Condensing boilers are water heaters fueled by gas or oil. They achieve high efficiency (typically greater than 90% on the higher heating value) by condensing water vapour in the exhaust gases and so recovering its latent heat of vaporisation, which would otherwise have been wasted. This condensed vapour leaves the system in liquid form, via a drain. In many countries, the use of condensing boilers is compulsory or encouraged with financial incentives. Condensing boiler manufacturers claim that up to 98% thermal efficiency can be achieved,compared to 70%-80% with conventional designs (based on the higher heating value of fuels). Typical models offer efficiencies around 90%, which brings most brands of condensing gas boiler in to the highest available categories for energy efficiency. In the UK, this is a SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK)[6] Band A efficiency rating, while in North America they typically receive an Eco Logo and/or Energy Star Certification. Most non-condensing boilers could be forced to condense through simple control changes. Doing so would reduce fuel consumption considerably, but would quickly destroy any mild steel or cast-iron components of a conventional high-temperature boiler due to the corrosive nature of the condensate. For this reason, most condensing boiler heat-exchangers are made from stainless steel or aluminum/silicon alloy. External stainless steel economizers can be retrofitted to non-condensing boilers to allow them to achieve condensing efficiencies.


When condensing boilers don't fit the budget or the design there are always mid-efficiency boilers which can do the job. These boiler run at approximately 75-85% AFUE and typically come in two different styles. Cast Iron: Cast iron boilers are brutes and when properly installed have an exceptionally long life span. The downside to these boilers is lower efficiency and larger size (and weight). Due to the material, cast iron boilers take a long time to heat up and must maintain adequate internal temperatures to prevent premature failures. This requirement prevents them from achieving the types of efficiency that a condensing or even a copper fin tube boiler may achieve. Copper Fin: Copper fin boilers are much smaller, lighter and can be more efficient then cast iron cousins. These boilers heat up much quicker and can run at lower internal temperatures increasing efficiency. The downside to copper fin tube boilers is an estimated shorter life span but the smaller size and increased efficiency balance that out.


Cold Water Sandwich

This occurs when someone calls for hot water, stops, and then calls for hot water again. The tankless water heater will have to re-ignite during the second call allowing some cold water through in the process. This results in cold water being sandwiched in between the hot water.