Ventilation is the process of changing or replacing air in any space to control temperature or remove any combination of moisture, odors, smoke, heat, dust, airborne bacteria, or carbon dioxide, and to replenish oxygen. Ventilation includes both the exchange of air with the outside as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air quality in buildings. Methods for ventilating a building may be divided into mechanical/forced and natural types.[16]

Our furnace quit lighting yesterday. I called Cool Tech around 7pm and they offered to come out after hours, but I chose to set up an appointment today. The technician John called me at 7:30am and was there about 8am as promised. He was very courteous and replaced the igniter quickly. The heater is back to working properly. This is my second time hiring Cool Tech and they will continue to be my go-to heating and air conditioning guys.


Hospital operating theatres, in which air is filtered to high levels to reduce infection risk and the humidity controlled to limit patient dehydration. Although temperatures are often in the comfort range, some specialist procedures, such as open heart surgery, require low temperatures (about 18 °C, 64 °F) and others, such as neonatal, relatively high temperatures (about 28 °C, 82 °F).
Variable-speed technology allows more energy saving potential and improved comfort levels throughout the home.  The ability of the system to automatically adjust speeds according to the needs of the home ensures the right amount of comfort control, right when you need it.  Outside temperatures rarely, if ever, require your HVAC system to operate at 100% capacity.  Variable-speed units determine optimal cooling needs and vary speeds in increments between 40% and 100%.  Not only does this tailor comfort, but by running at lower speeds and consuming less power, you’ll save a significant amount off monthly utility expenses.
An important component of natural ventilation is air change rate or air changes per hour: the hourly rate of ventilation divided by the volume of the space. For example, six air changes per hour means an amount of new air, equal to the volume of the space, is added every ten minutes. For human comfort, a minimum of four air changes per hour is typical, though warehouses might have only two. Too high of an air change rate may be uncomfortable, akin to a wind tunnel which have thousands of changes per hour. The highest air change rates are for crowded spaces, bars, night clubs, commercial kitchens at around 30 to 50 air changes per hour.[17]
Air changes per hour Bake-out Building envelope Convection Dilution Domestic energy consumption Enthalpy Fluid dynamics Gas compressor Heat pump and refrigeration cycle Heat transfer Humidity Infiltration Latent heat Noise control Outgassing Particulates Psychrometrics Sensible heat Stack effect Thermal comfort Thermal destratification Thermal mass Thermodynamics Vapour pressure of water
We believe that the key to our growing business success is our front-liners. Our team is composed of highly-trained technicians, electricians, and building professionals who are dedicated to providing excellent service. They work with clients to understand their needs and provide the most suitable but cost-effective solutions to property maintenance.
This information is not intended as an offer to sell, or the solicitation of an offer to buy, a franchise. It is for information purposes only. Read More Currently, the following states regulate the offer and sale of franchises: California, Hawaii, Illinois, Indiana, Maryland, Michigan, Minnesota, New York, North Dakota, Oregon, Rhode Island, South Dakota, Virginia, Washington, and Wisconsin. If you are a resident of or want to locate a franchise in one of these states, we will not offer you a franchise unless and until we have complied with applicable pre-sale registration and disclosure requirements in your state. Read Less Aire Serv is a registered trademark of Aire Serv LLC © Aire Serv | All rights reserved | All Aire Serv franchise locations are independently owned and operated.
An annual inspection of your unit can ensure that the various potential problems mentioned above are detected early, and before they require complete replacement. During this inspection, for instance, a professional might find small cracks in your heat exchanger or a faulty seal in your blower motor. Some manufacturer's warranties even require these annual inspections to maintain validity. Typically, your furnace inspection will cost between $80 and $150 depending on the area in which you live and the professional you work with.
Natural gas furnaces operate similarly to the above, using a pilot light to ignite the burners and heat up the air. Also similar to propane gas, your average repair costs for a natural gas furnace will range anywhere from $125 for small repairs to $1,200 if you have to replace the entire heat exchanger. The difference between both options is not necessarily the actual furnace, but the type of gas used to burn through it and heat your home. As a result, the repair costs tend to be close to identical.
Some systems include an "economizer mode", which is sometimes called a "free-cooling mode". When economizing, the control system will open (fully or partially) the outside air damper and close (fully or partially) the return air damper. This will cause fresh, outside air to be supplied to the system. When the outside air is cooler than the demanded cool air, this will allow the demand to be met without using the mechanical supply of cooling (typically chilled water or a direct expansion "DX" unit), thus saving energy. The control system can compare the temperature of the outside air vs. return air, or it can compare the enthalpy of the air, as is frequently done in climates where humidity is more of an issue. In both cases, the outside air must be less energetic than the return air for the system to enter the economizer mode.
*We work on all brands: Adams, Aire-Flo, Amana, Arcoaire, Armstrong, Beutler, Bryant, Carrier, Centurion, Coleman, Comfortmaker, Cozy, Daikin, Day & Night, Dayton, Ducane, Emerson, Empire, Evcon, Fedders, Friedrich, Frigidaire, Fujitsu, Gaffers & Statler, General Electric, Gibson, Goldstar, Goodman, GMC, Haier, Heil, Honeywell, Intertherm, Janitrol, Kenmore, Lennox, Luxaire, Maytag, Mitsubishi, Payne, Rheem, Ruud, Samsung, Sanyo, Sears, Sharp, Spartan, Tappan, Tempstar, Thermal Solutions, Trane, Utica, Weatherking, Westinghouse, Whirlpool, Williams, York, and Zephyr.
An electric furnace provides warmth by moving air over and through a series of coils. Ductwork and vents then distribute that air to the individual rooms in your home. Repair costs will depend on both the brand and the exact nature of the problem, but tend to be lower than some of the options above. That's because the units are small, and issues tend to be contained within the heating elements themselves. Expect to spend less than $300 on your electric furnace repair, depending on the exact problem.
Finally, don't underestimate the thermostat as a potential reason why your furnace is not working. Everything on the heating unit itself may function perfectly, but your home still will not heat right if the console you use to set the temperature doesn't communicate your input. A faulty thermostat can either be due to the wall unit itself, or the wiring that connects it to your furnace. Average thermostat repair costs are between $108 and $282, including labor. Replacement costs, of course, depend on the thermostat you choose. Visit our thermostat repair cost guide to learn more about this type of issue.
The main purpose of your furnace filter is to ensure that none of the additional materials your fans pull back into the unit - such as hair and dust - actually damage the furnace or its parts. In the process, it also improves air quality in your home. Some annual inspections will include changing and cleaning this part of the unit. That said, you can also clean or change your furnace filteryourself. Costs for new filters range based on brand, but tend to be around $30.
The condensed, pressurized, and still usually somewhat hot liquid refrigerant is next routed through an expansion valve (often nothing more than a pinhole in the system's copper tubing) where it undergoes an abrupt reduction in pressure. That pressure reduction results in flash evaporation of a part of the liquid refrigerant, greatly lowering its temperature. The cold refrigerant is then routed through the evaporator. A fan blows the interior warm air (which is to be cooled) across the evaporator, causing the liquid part of the cold refrigerant mixture to evaporate as well, further lowering the temperature. The warm air is therefore cooled and is pumped by an exhaust fan/ blower into the room. To complete the refrigeration cycle, the refrigerant vapor is routed back into the compressor. In order for the process to have any efficiency, the cooling/evaporative portion of the system must be separated by some kind of physical barrier from the heating/condensing portion, and each portion must have its own fan to circulate its own "kind" of air (either the hot air or the cool air).
×