The 2nd-century Chinese mechanical engineer and inventor Ding Huan of the Han Dynasty invented a rotary fan for air conditioning, with seven wheels 3 m (10 ft) in diameter and manually powered by prisoners of the time.[6] In 747, Emperor Xuanzong (r. 712–762) of the Tang Dynasty (618–907) had the Cool Hall (Liang Dian 涼殿) built in the imperial palace, which the Tang Yulin describes as having water-powered fan wheels for air conditioning as well as rising jet streams of water from fountains. During the subsequent Song Dynasty (960–1279), written sources mentioned the air conditioning rotary fan as even more widely used.[7]


If your home is not heated using forced air, chances are a boiler will make sure you stay warm during cold nights. A hot water system delivers hot water through a network of pipes that run to every room in your house. The heating effect gets maximized through radiators. The most common issues with hot water heating tend to be not be major, but small problems that add up over time. Mineral deposits within the water tank, a pilot light malfunction, or an issue with a radiator itself can require professional repair. On average, you will pay between $183 and $582 for these problems. The exact amount will depend on the exact problem, as described in our boiler repair cost guide.
Trying to replace an HVAC unit when out of town isn't easy, but Gator Air made it seamless. I was able to quickly schedule the estimator to come to my property and I was emailed several options. I was never pushed to make a decision or "sold" unwanted options. The installers were punctual and professional. Outstanding follow up too. I highly recommend!
As touched on by their name, heat pumps function by transferring heat energy indoors during the winter and outdoors from your home during the summer. They're often attached to air conditioning units, using the surrounding air to transfer energy. However, geothermal heat pumps and water source heat pumps are also available. The cost to repair a heat pump, again, depends on the specific problem. Replacing a faulty thermostat may cost up to $300 including labor, while a worn or damaged defrost control board can set you back up to $600. For more details on your potential repair costs using this heating source, visit our heat pump repair cost guide.

We had an exceptional experience with Gator Air, in particular Carlos. He presented us with quotes for different types of AC units, told us facts about said units and left us to make our decision. No high pressure sales. The installers were professional and cleaned up when they were through. A nice surprise was the 1 year free maintenance of the unit. We belonged to the Gator Club so to not have to pay it for the next year was an added bonus. Thank you GatorAir for making the experience an enjoyable one.
Whole-house fans have helped cool homes for a century. The basic design is simple: An attic-mounted fan pushes hot air out through attic vents and draws cooler, outside air in through open doors and windows. This rapid air exchange—large fans can purge a house of hot air in two to three minutes—not only removes built-up heat but also creates a pleasant breeze.

Air-source heat pumps are more popular in milder winter climates where the temperature is frequently in the range of 4–13 °C (40–55 °F), because heat pumps become inefficient in more extreme cold. This is because ice forms on the outdoor unit's heat exchanger coil, which blocks air flow over the coil. To compensate for this, the heat pump system must temporarily switch back into the regular air conditioning mode to switch the outdoor evaporator coil back to being the condenser coil, so that it can heat up and defrost. A heat pump system will therefore have a form of electric resistance heating in the indoor air path that is activated only in this mode in order to compensate for the temporary indoor air cooling, which would otherwise be uncomfortable in the winter.
The Environmental Protection Agency (EPA) requires that all technicians who open a system containing a controlled refrigerant be certified to do so. There are four levels of certification, one of which is a “universal” certification to allow the HVAC technician to work on any type of equipment containing refrigerant. Your HVAC technician should be certified as “Level II Certified” at a minimum or, preferably, “Universal Certification” to work on your central air conditioner. Obtaining this certification information from your professional HVAC technician may be required in the event you are working with a realtor to sell your home. Costs for certification average $40 to $240.
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).
I'm looking about spanning 15' for a gazebo. trying to figure out what dimension beams I need. The Gazebo will be 15'x10'. How big will the beams have to be. at 1/2 the distance on 15' I will have a perpendicular beam running to carry 2x4's running parallel to 15' beam edge. I live in California in there with be no roofing material.. I will be using redwood for lumber Thanks
On average, furnace repair costs $287 nationally, with some homeowners spending as little as $60 while others paying $900 for furnace maintenance. Repairs to an electric furnace can run you $300 or less, while gas furnace repairs can be more complex and range from $375 to $1,200, depending on the what needs service. Most homeowners spend between $131 and $454 to fix their furnace. Here is what you need to know, along with the various factors that could affect the price of your furnace repair.
Packaged terminal air conditioner (PTAC) systems are also known as wall-split air conditioning systems.[36] They are ductless systems. PTACs, which are frequently used in hotels, have two separate units (terminal packages), the evaporative unit on the interior and the condensing unit on the exterior, with an opening passing through the wall and connecting them. This minimizes the interior system footprint and allows each room to be adjusted independently. PTAC systems may be adapted to provide heating in cold weather, either directly by using an electric strip, gas, or other heater, or by reversing the refrigerant flow to heat the interior and draw heat from the exterior air, converting the air conditioner into a heat pump. While room air conditioning provides maximum flexibility, when used to cool many rooms at a time it is generally more expensive than central air conditioning.
If your furnace needs to be repaired, you’ll want to find a qualified heating, ventilating and air conditioning (HVAC) repair technician. Each state has its own licensing requirements; some require all HVAC technicians to have an HVAC license, while others only require someone operating an HVAC service and installation company with employees to hold a contractor’s license. For example, in Alabama, the Alabama Board of Heating Air Conditioning, and Refrigeration Contractors regulates licensing, while in Kansas there is no state regulatory body and HVAC licensing can vary by region. For simple furnace repairs like changing out a filter, a trusted handyman can probably handle the job, but a trained professional should be hired for tasks like replacing a gas valve, installing a new inducer fan motor or other critical furnace repair jobs that involve dealing with gas leaks or other dangerous conditions. For more, check out our tips for smart hiring on Thumbtack.
Heating, ventilation, and air conditioning (HVAC[1]) is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation, as HVAC&R or HVACR or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).
Its unique feature is the presence of one main external unit that connected to several indoor units. Such systems might be the right solution for maintaining the microclimate in several offices, shops, large living spaces. Just few of outdoor units do not worsen the aesthetic appearance of the building.The main external unit can be connected to several different indoor types: floor, ceiling, cassette, etc.
Your HVAC professional can also help you verify that your system is properly matched by providing you with an AHRI Certificate of Certified Product Performance upon request. The certificate verifies that the outdoor unit (condenser) and the indoor unit (evaporator) combination has been certified as a matched system by the Air Conditioning, Heating and Refrigeration Institute (AHRI). For higher efficiency systems, this certification may help you obtain a rebate from your utility or local municipality if you have to replace your unit in whole or in part. Not all areas offer a rebate, but your technician will likely be able to provide information about the certification process. Fees for performing this certification vary, but generally are relatively inexpensive.

I'm looking about spanning 15' for a gazebo. trying to figure out what dimension beams I need. The Gazebo will be 15'x10'. How big will the beams have to be. at 1/2 the distance on 15' I will have a perpendicular beam running to carry 2x4's running parallel to 15' beam edge. I live in California in there with be no roofing material.. I will be using redwood for lumber Thanks
Given the broad price ranges above, it's easy to recognize that the cost of your furnace repair varies drastically based on which parts need attention. As a result, it makes sense to gain a better understanding of the parts that heat your home, and how much they cost to repair. Repairing or replacing your furnace’s blower motor can cost you anywhere between $150 and $450, depending on the extent of the damage. Heat exchanger repair costs can vary greatly, from as little as $100 for a simple fix to as much as $1,200 for a full replacement. Repairing a furnace igniter will only cost you $300 at most, while flame sensor repairs generally fall between $80 to $250. The average cost to repair your Thermostat will range from $108 to $282.
The Chartered Institution of Building Services Engineers is a body that covers the essential Service (systems architecture) that allow buildings to operate. It includes the electrotechnical, heating, ventilating, air conditioning, refrigeration and plumbing industries. To train as a building services engineer, the academic requirements are GCSEs (A-C) / Standard Grades (1-3) in Maths and Science, which are important in measurements, planning and theory. Employers will often want a degree in a branch of engineering, such as building environment engineering, electrical engineering or mechanical engineering. To become a full member of CIBSE, and so also to be registered by the Engineering Council UK as a chartered engineer, engineers must also attain an Honours Degree and a master's degree in a relevant engineering subject.
In the most general sense, air conditioning can refer to any form of technology that modifies the condition of air (heating, (de-) humidification, cooling, cleaning, ventilation, or air movement). In common usage, though, "air conditioning" refers to systems which cool air. In construction, a complete system of heating, ventilation, and air conditioning is referred to as HVAC.[3]
Terrible - Explained to tech that we had cold air on heat status. I placed Thermostat on emergency heat and was able to get some heat. I told him TXU had installed a a new thermostat and I think he may have installed it incorrectly but wasn't, sure. He said it would cost us more money if he fixed problem if there was one. He said I could pay for it and get reimbursed from insurance company. When he said it would cost us money I said I would live with it. I plan on calling a reputable repair company. He did not check furnace or temperature of house
Vredevoogd Heating & Cooling stands behind its services and products with the strongest guarantees you’ll find anywhere. When you invite us into your home to service or install your HVAC system or do Furnace Repair work in Grand Rapids and beyond, we perform our job with an outstanding level of care and efficiency. Having served Michigan for 54 years, we never rest on our laurels. To remain the best, we intend to give our best every time, every job.
If your furnace’s motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. Replacing it is an easy fix. First, turn off all power to the unit and turn off the gas at the gas valve that serves the furnace. Remove the door on the front of the furnace cabinet to give you access to the blower (it might be on a slide-out drawer.) Check the number stamped on the belt and get an exact replacement from a home center or heating supply outlet.
Because an air conditioner moves heat between the indoor coil and the outdoor coil, both must be kept clean. This means that, in addition to replacing the air filter at the evaporator coil, it is also necessary to regularly clean the condenser coil. Failure to keep the condenser clean will eventually result in harm to the compressor, because the condenser coil is responsible for discharging both the indoor heat (as picked up by the evaporator) and the heat generated by the electric motor driving the compressor.

The use of furnaces, space heaters, and boilers as a method of indoor heating could result in incomplete combustion and the emission of carbon monoxide, nitrogen oxides, formaldehyde, volatile organic compounds, and other combustion byproducts. Incomplete combustion occurs when there is insufficient oxygen; the inputs are fuels containing various contaminants and the outputs are harmful byproducts, most dangerously carbon monoxide, which is a tasteless and odorless gas with serious adverse health effects.[14]


1) Your air conditioner is not working at all. Before calling in a professional to address this issue, you may want to check a few things yourself. Check to see if your thermostat is set to “cool”. Confirm that your designated cooling temperature is less than the temperature of the room or home. If everything is set correctly, check the electrical panel to be sure you do not have a tripped breaker. If these things all check out and your air condition unit is still not working, it is time to call in a professional.
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).
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