Knowing about the basics of how your home’s appliances work means you’re more likely to be able to speak to an electrician, plumber, mechanic, carpenter or technician and help them get to the root of the problem quickly, saving you money. Here is a short list of the HVAC terms every homeowner should know to speak with a duct cleaner or HVAC technician with confidence.
HVAC – Heating, Ventilation and Air Conditioning (usually pronounced H-VAC). This term refers to the overall heating, cooling and air filtering systems in your home, also used in commercial buildings. Its purpose is to create a comfortable environment for its inhabitants.
A/C – Air Conditioner. These are appliances designed to remove heat (humidity from a home or building for increased comfort in warm weather. These can be anything from central air, window-mounted or heat pumps (to name a few).
AFUE – annual fuel utilization efficiency – furnace efficiency. A standard efficiency gas furnace provides about 80% fuel combustion efficiency. A high efficiency furnace process 90% heated air for 10% exhaust out the flue
Airflow – in a closed loop system such as a furnace in your home, air being bushed through the ducts by your blower needs to also come back to the air handler through the cold air returns to have proper air flow. The more balance the system, the more efficient it will be. Air moves through your home by moving high pressure air through your ducts to low pressure areas.
Airflow Rate (CFM) – cubic feet per minute is the measure of the volume of air passing through your air handler. Most Canadian homes with furnaces move about 1000 cubic feet per minute (1.5 million cubic feet /day).
BTU* – British Thermal Units – an imperial unit of measuring energy, it is commonly used today when referring to energy produced by heating & cooling systems. 1BTU= energy required to raise 1 pound of water by 1°F (1 BTU=1,055 joules). Typical home heating/cooling appliances range from 4,000-12,000 BTU.
Carbon monoxide detector – when a furnace is not operating properly or is blocked, combusted gas in a furnace may escape into the home causing carbon monoxide poisoning. Carbon monoxide detectors are mandatory in Ontario near sleeping areas, as these gases are not detected by human scent.
Coils – Heating & Condensing – are wound metal coils in the furnace (air handler) using for heating. A different set containing freon is used for cooling.
Controller – the furnace’s controller handles the turning on and off of the furnace which is regulated by a thermostat, and resides inside the air handling unit.
Ductwork – the large hollow metal rectangular or round pipes visible in the basement or utility room of your home that carry treated air to every room of your home.
Cold Air Returns – when treated air enters a room, it needs to have a way to return back to the furnace for proper flow. Cold air returns are vents between studs found near the bottom of a wall that handle this.
Dehumidifier – an appliance that removes humidity from air. This can include a dehumidifier or an air conditioner. A dehumidifier has the added benefit of removing some odors in the air which are usually carries by moisture.
Diffuser – a diffuser works to redirect air around a room so it does not go in just one direction. As more common in commercial buildings with larger ducts, vents are often used in place of diffusers
Flue – a gas fired furnace produces exhaust with the combustion of the hydrocarbon and oxygen. This exhaust is sent through the flue safely to the outside.
Grille – the front vent on your air handler that allows air in to be heated or cooled
Heat Pump – a mini-split heat pump has an outdoor condenser unit and indoor air handler. It basically works by moving heat from one area (either indoor or outdoor) to the opposite side (outdoor or indoor). One of the most brilliant features of heat pumps is they can be used in winter to heat, and in summer to cool (just by reversing its function by a click of a button).
RTU – Rooftop Unit – typically seen in commercial spaces (condos, apartments, commercial buildings), RTUs often contain heating, a/c and ventilation in one, and often recirculates some of the existing air of the building with fresh outdoor air.
Refrigerant – fluid (typically freon) used to cool an area by transferring cold fluid coils into a room, removing the heat outside.
Split System (zoned) – in more advanced HVAC systems, it is possible to control the temperature of specific zones or even rooms in a home. Each zone has its own thermostat and duct-controlling vents to affect the temperature of that zone. The vents are electronically controlled by the controller which opens or closes vents within the ducts.
Thermostat – perhaps the most known device in an HVAC system, the thermostat is set manually or remotely (by a smart app) in order to regulate the temperature of a home. Larger homes & luxury homes will have more thermostats to regulate zones (see Split System). The thermostat contains a coil that expands when heated to activate a mercury switch turning off the furnace a degree or two above the set point. Once the house cools down a few degrees below the set point, the coil contracts tilting the mercury switch to another position, turning on the furnace cycle again. Learn more about smart homes: https://www.heatingontario.ca/the-emergence-of-smart-buildings-and-smart-home-hvac/
*Air Conditioner/Heating Room Unit BTU Chart (mini-split heat pumps)
Typical Room Dimensions:
100-200 sq ft
10×10, 12×12, 14×14 bedrooms
200-300 sq ft
16×16, living rooms
300-400 sq ft
18×18, 20×20 large rooms
400-500 sq ft
22×22 room, studio apartment
Larger units do NOT mean a room will cool faster, so it advisable to stay within recommended cooling capacities. However, if you are using a heat pump to cool an entire floor, you will obviously need a larger unit to accommodate all the rooms. Central air systems which cover an entire home will have BTUs ranging from 20,000BTU to 70,000BTU.
The amount of heating and cooling BTUs required are dependent on a number of factors: climate, quality of insulation & square footage are the biggest factors. In colder climates, there will be a higher heating BTU factor than cooling, and vice-versa. In moderate climates, a general rule is to multiply the square footage of the home by 20BTU (for example 1500 sq.ft. x20 = 30,000BTU). In colder climates, it is more accurate to use a factor of 30-40X (1500 sq.ft. x40 = 60,000BTU). In that same location in summer, it may only take 20,000BTU to cool the place. In homes that have poor insulation, a factor of 80 in cold climates may be more accurate.
If you require odour removal, furnace maintenance, home/office sanitization or duct cleaning, feel free to call us for a free quote at: 416-410-3777 or fill out the form to the right and we’ll get back to you as soon as we can.