Typical BTU Cooling Capacity Range for Air Conditioners

Portable, window, or through-wall air conditioners are typically described by their manufacturer as suited for

Single Room Air Conditioner Capacity - typically for rooms up to 20' x 20' or 400 sq.ft. in area. BTUs in this product range are typically from 6,000 BTUh to 10,000 BTUh.


Multiple Room Air Conditioner Capacity - typically for a total area of up to 800 sq.ft. BTUs in this product range are typically from 10,000 BTUh to 16,000 BTUh.

Large Capacity Air Conditioner Capacity - typically for multiple rooms or very large rooms up to a total area from 900 sq. ft. to 2,000 sq.ft. BTUs in this product range are typically from 16,000 to 28,000 BTUh.

Central Air Conditioning - typically to cool an entire floor or multiple floors in a home.
 
To determine the BTUs needed to cool a given space follow this procedure:
 
1.    Calculate the total square feet to be cooled: Measure the size of the room (or rooms) to be cooled, to obtain total square feet. Multiply room length by width for each room and if there are multiple rooms, add the room areas together to get a single number.
 
2.    Read the Base BTUs needed from Table 1 below
 
3.   Add additional BTUs for these factors:
 
4,000 BTUs for each room below a ceiling or roof which is not insulated


+ 4,000 BTUs for a home or residential kitchen included in the cooled area

+ 1,500 BTUs for each window which receives significant daily sunshine

+ 1,500 BTUs for a room over a kitchen or boiler room IF the kitchen or boiler room is actively producing heat during the cooling period

+ 600 BTUs per person over two, if more than two occupants will be occupying the room during the cooling period

4.      Subtract BTUs from the total required if these factors are present:

- 1,000 BTUs if the room is on the shaded side of the building


5.     Calculate the final total BTUh needed from the above steps. This should place you in the right range of cooling capacity needed. Review the warning below about buying an oversized air conditioner.
 
The table below gives recommended air conditioning BTU's necessary to cool a single room. The data in the table assumes that the ceiling over the room is insulated and that the room is not over or is not itself a special heat-producing area such as a kitchen or boiler room.
 

To cool this area, look for this size air conditioner

 

100 to 150 square feet: 5,000 BTUs

 

150 to 250 square feet: 6,000 BTUs

 

250 to 300 square feet: 7,000 BTUs

 

300 to 350 square feet: 8,000 BTUs

350 to 400 square feet: 9,000 BTUs

400 to 450 square feet: 10,000 BTUs

450 to 550 square feet: 12,000 BTUs

550 to 700 square feet: 14,000 BTUs

700 to 1,000 square feet: 18,000 BTUs

1,000 to 1 400 square feet: 24,000 BTUs

High Performance HVAC Air Handler Components

Air Handler Components

This article will take different types of air handlers and disassemble them part by part to give you a good description of each part and hopefully a better understand of the air handler in general. Most of the components associated with the air handler are in the air handler. However, there are a few components which are not in the air handler but associated with the air handler. There are some hot water and cold water coils which are not fixed into the air handler but downstream in the ductwork. There are also some gas and electric duct heaters which are mounted in the ductwork and completely reliant on the air handler for air flow. These systems will also be covered and hopefully this article will offer you a comprehensive look at the air handler, all its parts, and how it functions.

The Air Handler Cabinet

The air handler cabinet is comprised of sheet metal. Manufacturers use a heavy gage sheet metal for durability and usually give the cabinet a good finish to prevent rust especially in moist environments where air handlers usually operate. The heavy gage sheet metal for durability is generally required to meet code requirements which many manufacturers try to exceed for compliance reasons. Some air handler cabinets can be disassembled and reassembled at the job site so they can fit in tight places. Another reason for disassembly is for a multi-use air handler that can be used for up flow, down flow, or for horizontal flow left to right or horizontal flow right to left. Whatever the job calls for the multi-use air handler can be quickly converted in the field without special ordering from the manufacturer.

Air Handler Plenum Transitions

When the air handler is installed the HVAC contractor has to fit the ductwork up to the new air handler. Depending on the type of ductwork and the type of air handler can depend on the type of material selected to make this transition to the ductwork. It is recommended that sheet metal be used for this transition especially if the heating system is in the air handler. If sheet metal is not used in an air handler with the heating system inside the air handler then the installation could fail a code inspection. Always read the manufacturer’s instructions on this as the temperatures inside the supply air side of the air handler can ignite combustible materials. The HVAC contractor will be fully aware of this and most contractors use sheet metal to make these transitions to other types of ductwork. If the ductwork is round then a square to round plenum transition will usually be custom made by the contractor or by a sheet metal shop which the contractor utilizes. If the ductwork is square then a plenum transition will be made to fit the air handler and the duct work together. This usually requires a highly skilled sheet metal mechanic to custom make these plenum transitions. After the plenum transitions are installed then an insulation blanket is added to the plenum transitions to ensure there is no heat loss or heat gain and also to provide a vapor barrier so that when the air in the duct work is less than the dew point temperature the duct work and the plenum transition does not sweat. It is very important to maintain this vapor barrier throughout the ductwork. If one piece of ductwork, whether this is in the plenum transition or ductwork, loses the vapor barrier it can have a domino effect throughout the whole ductwork system as moisture fills the ductwork. As the ductwork insulation gets wetter the R-value of it decreases and it begins to fall off the ductwork. Eventually all of the ductwork insulation is penetrated by moisture and the insulation needs to be replaced. If it is not replaced moisture problems occur with mold, mildew and other problems associated with moist environments.

The Air Handler Control Panel

Most air handler control panels contain high voltage and low voltage wiring, relays, and or a control board. The transformer is usually located in the air handler control panel along with either control wire splices coming from the thermostat and the condenser unit. The air handler control panel is generally the central location where the control wiring meet and are distributed to the proper locations for control. Usually, all control voltage for the thermostat, condenser, and air handler originates from the air handler control transformer. This transformer is a step down transformer which turns high voltage into low voltage. Many un-fused transformers have been burned up by homeowners who change the thermostat without first turning the power off to air handler first. Subsequently, this results in a service call to an HVAC contractor who replaces the transformer and finishes the thermostat installation. There are many different types of controls and ways to control an air conditioning and heating system and we will do our best to describe as many as possible. If you have any questions or would like to suggest a control method which you are familiar with please don’t hesitate to use our forum or the High Performance HVAC contact page to make this suggestion.

The Air Handler Control Panel: Fan Relay Control

Other components in the air handler is a fan control relay or fan control board. This gets its signal from the thermostat on a call for cooling, heating, or if the fan selector switch on the thermostat is set to the on position. Depending on the type of heating system you have the blower may turn on right away or it may not turn on right away. This small time delay for heating is to allow the heat exchanger to heat up before the fan turns on there is also a small time delay for both heating and cooling to allow for the conditioned air, whether it be heated or cooled, to be distributed throughout the ductwork and in to the spaces where conditioning is necessary. This time delay allows for the heat exchanger to cool off and for usable heat to be used in the spaces instead of letting it dissipate in the air handler or up the flue. For cooling this time delay takes advantage of a cool evaporator coil so that it can absorb a little more heat out of the air for conditioning. Some gas and oil furnaces have the heating fan control circuit run outside of the control and to a different control which is mounted near the heat exchanger and has a temperature probe which goes into the heat exchanger. This control is called a fan-limit switch and you will find it in gas furnace air handlers and oil fired furnace air handlers. This temperature probe is for heating fan control and completely bases the control of the fan on the temperature of the heat exchanger. If the temperature reaches a certain manually set temperature the fan energizes. When the temperature of the heat exchanger cools the fan de-energizes. On some of these fan-limit controllers the white wire from the thermostat also runs through these controls. This white wire controls the burner and if the temperature of the exchanger exceeds a safe limit this fan-limit switch controller will turn the burner off and keep the fan energized to dissipate the heat in the system.

The Air Handler Control Panel: Heat Relays


Depending on the type of heat (if you have a hot water boiler utilized for heating this does not apply) the air handler control panel will also have some heat relays or a heating control board to energize the heating system in the air handler. This can be a very complex circuit as it should run through several safety switches before it allows the heat relay to energize. For electric heat you should have some Klixon safety switches and a thermal safety switch which actually melts if it reaches a set temperature which is dangerous. If there is a problem with any of these switches they will prevent the air handler heating relays or control board from energizing the heat in the air handler. This is for your safety and the safety of the structure to prevent a fire or fire hazard. Some of these switches, especially in gas furnaces, are manual reset. These particular manual reset switches are generally referred to as roll-out switches as they prevent a roll-out fire fro occurring. On occasion, these switches will give you nuisance trips and its important to note the exact switch that tripped before resetting and to not reset this switch more than once. The best thing to do is to call an HVAC heating and air conditioning contractor if you have this problem or a problem with any of the safety switches. A dangerous condition may exist and if you continue to manually reset these switches you could make the problem worse.

How To Repair Room Air Conditioners

Room air conditioners, also called window units, work the same way central air conditioners do. They are smaller than central systems and often more expensive to operate. Depending on its size, a room unit may cool only the room in which it's located, or it may be able to cool adjoining rooms as well.


Sandwiched between the coils are a compressor, two fans, a motor, and thermostat controls. Dirt is the biggest enemy of window air conditioners; it can lower the efficiency of the evaporator coil, block the operation of the fan that blows out the cool air, clog filters, and block drain ports.

Both of the major components of a room air conditioner are contained in one housing.

The condenser coil faces outside, and the evaporator faces inside.

The coils, the compressor, and the motor of a room air conditioner are sealed components, so any repairs to them should be left to a professional service person. However, you can make minor repairs, and regular maintenance will keep your unit running well. When extensive repairs are needed, you can also save the cost of a service call by removing the air conditioner from its mounting and taking it to the repair shop.

During the winter, room air conditioners should be protected from the elements. Either remove the unit from its mounting and store it or cover the outside portion of the unit with a commercial room air conditioner cover or with heavy plastic sheeting, held in place with duct tape.

Caution: Before doing any work on a room air conditioner, make sure it's unplugged. Room air conditioners have either one or two capacitors, located behind the control panel and near the fan. Capacitors store electricity, even when the power to the unit is turned off. Before you do any work on an air conditioner, unplug it and discharge the capacitor or you could receive a severe shock. The unit's owner's manual will show the location of capacitors and tell how to discharge them. Otherwise, let an air conditioning technician do it.

How to Repair Central Air Conditioners

Central air conditioners have two separate components: the condenser and the evaporator. The condenser unit is usually located outside the house on a concrete slab. The evaporator coil is mounted in the plenum or main duct junction above the furnace.


Most central air conditioners are connected to a home's forced-air distribution system. Thus, the same motor, blower, and ductwork used for heating are used to distribute cool air from the air conditioning system. When a central air conditioner is operating, hot air inside the house flows to the furnace through the return-air duct. The hot air is moved by the blower across the cooled evaporator coil in the plenum and is then delivered through ducts to cool the house. When the air conditioner works but the house doesn't cool, the problem is probably in the distribution system.

Central air conditioners are made up of two separate components: the condenser unit,
located outside the house on a concrete slab, and the evaporator coil above the furnace.

Both the evaporator and the condenser are sealed. Therefore, a professional service person should be called for almost any maintenance other than routine cleaning. Central air conditioners should be professionally inspected and adjusted before the beginning of every cooling season. However, don't let your maintenance end with this annual checkup. While there aren't many repairs you can make yourself, there are specific maintenance procedures you can follow to keep your system operating at peak efficiency.

Caution: Before doing any work on an air conditioning system, make sure the power to the system, both to the condenser and to the evaporator assembly, is turned off.

CENTRAL HVAC

First things first. What does HVAC mean?


While the Energy Center usually tries to avoid the use of acronyms, HVAC is in common use in the heating and cooling industry. It stands for "heating, ventilation and air conditioning," three functions often combined into one system in today's modern homes and buildings. Warmed or cooled or dehumidified air flows through a series of tubes - called ducts - to be distributed to all the rooms of your house. A central HVAC system is the most quiet and convenient way to cool an entire home.



Unless you live in an amazingly temperate climate, the HVAC system in your home uses more energy and drains more energy dollars than any other system in your home. Typically, 44 percent of your utility bill goes for heating and cooling.


Like many other appliances, HVAC systems have improved in energy efficiency in the last decade. As a result, you can save money and increase your comfort by properly maintaining and upgrading your HVAC equipment.

Another development of the 1990s is the whole house approach to heating and cooling. Coupled with an energy efficient furnace, heat pump or air-conditioner, the whole house approach can have a great impact on your energy bills. By combining proper equipment maintenance and upgrades with appropriate insulation, weatherization and thermostat settings - properly regulated with a programmable thermostat, of course - you may be able to cut your energy bills in half.

All major appliances including gas furnaces, boilers, air conditioners and heat pumps sold in California meet the Title-24 energy efficiency standards. If you are thinking about purchasing a new central furnace, check the ENERGY STAR® database, which uses information supplied by the California Energy Commission. It displays information on most energy efficient appliances in a consumer-friendly, easy-to-use fashion.

Central Air Conditioning

Central air conditioning units are usually matched with a gas or oil furnace to provide heat through the same set of ducts.


There are also central HVAC units called heat pumps that combine both the heating and cooling functions. If you heat your home with electricity, a heat pump system is the most efficient unit to use in moderate climates. It can provide up to three times more heating than the equivalent amount of electrical energy it consumes. A heat pump can trim the amount of electricity you use for heating as much as 30 percent to 40 percent.

Even though air conditioners and heat pumps require the use of some different components, they both operate on the same basic principles.

WHOLEHOUSE FANS

Even if your home has air conditioning,
consider installing a whole house fan.
Whole house fans use far less energy
 than air conditioners and they cut
cooling costs. In fact, whole house
 fans typically use about one-tenth
of the electricity of comparably sized
air conditioners, and they are relatively
inexpensive to install. Used correctly,
they can help you cut your air
conditioning bills substantially.

Whole house fans are designed to operate in the early morning and after sundown, when the outside temperature drops below 80 degrees. The idea is to turn off the air conditioning and to turn on the whole house fan. With your windows open, fresh, cool air is drawn into your home, forcing out the hot air. Your entire house is then cooled by outside air, without the needed help of your air conditioner.

Remember not to run your air conditioner at the same time you use the whole house fan, and to keep most of your windows open when it's operating. Opening windows not only helps the air circulation, but it also prevents fumes or flames from your gas appliances and fireplace from being drawn back into your home.


While whole house fans may be placed in a number of locations, the most frequently used spot is the hallway ceiling. Louvers normally close off the fan when not in use so that conditioned air doesn't escape through it. When the fan is operating, however, these louvers open, allowing air to be blown into your attic.

Attics can be brutally hot on a summer's day. When heat is absorbed by your walls and ceilings, attic temperatures can climb to over 150 degrees. Even if your ceilings are well insulated and your home is air conditioned, this heat can seep from your attic down into your home. A whole house fan, however, draws cooler, outside air through your open windows and forces it through the attic and out through the roof vents. Your house and your attic are all cooled. Air conditioning alone doesn't offer that benefit.

Whole house fans are very powerful and need sufficient attic ventilation to be effective. Your contractor can help you determine the correct fan size, capacity and number of attic vents needed for your home.

window air conditioner

Crosley CA12ESR 12000 BTU window air conditioner

 
 
 
 
 
 




Room air conditioner by Crosley, puts out 12,000 BTU per hour and cools an area up to 490-640 sq feet.



This window unit has a pleated quick mount window kit, side louvers and handles for safe installation and service - no special tools needed and no mess in your room.


The Multi speed cooling system has a fully functional temperature sensing remote control with thermostat, 8-way direction control, an exhaust control and a fan only mode for removing circulating fresh outdoor air.

The easy access, up front electro-static filter helps remove dust and other foreign particles from the air. Just slide out for easy cleaning. The unit has a 5 ft power cord and plugs into a standard 3 prong socket and saves energy with an EER rating of 9.8, and a power-saver control that automatically turns off the compressor and fan when the selected temperature is reached and turns back on when needed.

Office air conditioning

If a workplace becomes too hot then staff effciency will be reduced. There are also health concerns as in extreme temperatures there is a risk of serious fatigue or heat stroke. Whilst British legislation does not set a maximum working temperature, it is interesting that the World Health Organisation recommends a maximum air temperature of 75°F/24°C for workers to work comfortably.


Uncomfortable levels of heat are more likely to cause accidents because it lowers concentration levels.

Putting aside the health and safety implications of having a hot working environment, by installing air conditioning the workplace becomes a much nicer place to spend a considerable part of your day-to-day life.


In order to calculate the size of air conditioner that you require you will need to know:

The floor area of the room

The size and position of the windows
The number of occupants (if any)
The heat generated by the equipment in watts
The heat generated by the lights in watts

Once you have this information perform the following calculation:

Room area (length in m x width in m) x 30
Length (m) x width (m) of south facing window x 870
Length (m) x width (m) of north facing window x 165
(if there are no blinds on the windows multiply windows results by 1.5, also if you are in the southern hemisphere reverse these conversion factors so a south facing is x 165 and a north facing is 870))
Number of occupants x 400
Wattage for all equipment, e.g. computers, faxes, printers, etc x 3
(the wattage for equipment is based on maximum power consumption)
Lighting wattage x 4.25

Add all your results together and divide by 3412. This is the size of air conditioner you require in kW.

Office air conditioning issues
Portable air conditioners are suitable for areas up to 38m2. Alternatively, portables are ideal for spot cooling certain areas within an office. However, for large offices and areas that require very quiet conditions, split systems should be installed.


If you are using portable air conditioners and are not near a window or door, then it is often possible to vent the exhaust hose up through a suspended ceiling system. The tiles can be easily pushed up or to the side.

If you are going to install a wall-mounted split system then this will involve installing a fan unit in the room to be cooled and an external unit on an outside wall. Most regions in the UK do not require you to obtain planning permission for this type of installation but some do. You will need to check with your local council if you are unsure

Always try to install the inside fan unit of a split system on an external wall as it removes the need to run piping along walls and can make condensate removal much easier as a condensate pump may not be required - a gravity drain can be used instead.

When considering the positioning of a split system, consider how the air flow will effect the people positioned closest to it. Being situated directly under a unit may be uncomfortable. Also, if you have a long area always try to have the air flow travelling down the length of the room rather than across.

Air conditioners will produce condensation internally on the cold surfaces of the unit. In portables this is dealt with either by pumping the moisture out of the vent hose, by incorporating an internal water tank that you will need to empty or through plumbing the unit in to the drain. In wall-mounted and through-the-wall systems, condensation is automatically drained outside of the building. On hot days this can be up to five litres.

An air conditioner will need servicing every six months to maintain efficient operation.

Many air conditioners can also heat making them useful in the winter as well as in the summer.

Coolair Evaporative Airconditioning

When the heat's on, your family can relax and enjoy low cost, whole of home

Coolair ducted evaporative air conditioning.

Coolair has been cooling Australians for over 30 years. Coolair provides low cost, high performance evaporative air conditioning that's built to last.

Repair or Replace Your Air Conditioner (AC)

Determining if you should Replace or Repair your Air Conditioner (AC)

It's a hot summer morning and you wake up to a house that feels like you left the furnace running all night. This is odd because you set the air conditioner to run before you went to bed. If your air conditioner is running hot air, you know you have a problem!


Your first instinct is to call for a quick repair job. Repair seems to be the least expensive way to go but it may not be at all. In the long run, replacing your broken unit might be the best way to go. How do you decide?

Making that decision to replace or repair can be a difficult one to determine when you are sweating buckets and just need to get the job done – now!

When deciding take into consideration the following:

Age of the system - Typically speaking an air conditioner is expected to last 12-18 years although there are numerous examples of air coonditioners that have been running much longer. (Your location, maintenance, and typical use of the A/C unit will impact this quite a bit.) If your air conditioner is coming up on the seventh year mark and simple repairs don't seem frugal, then you are likely going to want to opt for replacement. On the flip side, if your air conditioner has been operating for less than five years, you might want to consider repairing it since it likely has a number of good service years left.

Overall satisfaction of the system - If your air conditioner has been running well up until this time, you have reason to believe that it will continue to run well with a few repairs. At the same time, if your system has caused you any kind of headaches up until this time, you might feel now would be a good time to replace it.
Cost of operation - Many A/C units 15-20 years old could have a SEER rating that is 1/2 of current high efficiency units. That is essentially a 50% savings in energy which will impact your yearly cooling bills in a large way.
Cost to repair - If you are looking at spending $500 - $750 just to repair your old system now may be the time to replace it.
Cost to replace - When assessing whether or not to repair, always try to get a free estimate. Some repairs are just too costly to even consider and so in this case replacing will be the best way to go. Once you have your estimate this can guide your decision to repair or replace smartly. Remember that you want to make the best decision, not the cheapest one.
How often is the system used - A system that gets infrequent use due to your local climate may make repair seem a more fiscally responsible option.

DOUBLE-DECK BUS AIR CONDITIONER

DOUBLE-DECK BUS AIR CONDITIONER

The product is intended for double-deck bus. The integrated layout and impact structure help enhance the balance and stability of bus. The double-layer air channels make air flow more uniform, gentle and comfortable. The unit is provided with an imported condenser fan and evaporator blower of low power consumption, low noise, and long service life and other core components of international famous brands to guarantee the high quality of the product. The product features high cooling capacity, low power consumption and perfect system protection. It is easy to operate and convenient to service.

DOUBLE-DECK BUS AIR CONDITIONER

WINDWARD E SERIES

WINDWARD E SERIES

The product was introduced and developed in 2002 and officially launched in both domestic and international markets in the beginning of 2004. It was specially designed for medium and high-grade urban buses. The combination of advection design, windward layout and the use of small-pipe-diameter rifled copper pipes improves the heat convection efficiency of the condenser by 25~30%. The cooling capacity, energy efficiency ratio, cooling capacity weight ratio and other technical index have reached advanced world standard and shown marked energy saving advantages. The refrigerant filling amount of the system is 30% lower than other types of bus air conditioners. The integrated structure makes the unit more impact and all facilities of the whole bus easier. The product is extensively applied to the high-grade customers of main domestic public bus markets.

JYKT30E1/JYKT32E1/JYKT36E1                            JYKT24E1/JYKT26E1/JYKT28E1

Split AC Guide

Split AC Guide

1. Why choose a mini split air conditioner?

A mini split air conditioner is a cost effective alternative to central air conditioning. However, it is typically more expensive than a wall or window air conditioner and needs to be professionally installed. Since the compressor sits on the outside, the split air conditioner is very quiet and efficient. Also, since mini splits have no ducts, they avoid the energy losses associated with the ductwork of central forced air systems. Duct losses can account for more than 30% of energy consumption for space conditioning, especially if the ducts are in an unconditioned space such as an attic.

2. Are there additional benefits?

Mini split air conditioners are sometimes easier to install than other types of air conditioning systems. For example, the hook-up between the outdoor and indoor units generally require only a three inch hole through a wall for the conduit. Also, most manufacturers for this type of system will provide a variety of lengths of connecting conduits. This way, it is possible to locate the outdoor unit as far away as 50 feet from the indoor evaporator for cooling rooms on the front side of a building or house with the compressor in a more inconspicuous place on the outside of the building.

In comparison to other add-on systems, split air conditioners offer more flexibility in interior design options. The indoor air handlers can be suspended from a ceiling, mounted flush into a drop ceiling, or hung on a wall. Floor-standing models are also available. Most indoor units have profiles of about seven inches deep and usually come with sleek, high tech jackets. Many also offer a remote control to easily turn the split air conditioner on and off when it's positioned high on a wall or suspended from a ceiling.

Outdoor Compressor-Condenser AC Unit                               Indoor Wall Unit

3. What are mini split air conditioners?

Like central air conditioning units, mini split air conditioners have two main components: an outdoor compressor/condenser, and an indoor air-handling unit. A conduit, which houses the power cable, refrigerant tubing, suction tubing, and a condensate drain, links the outdoor and indoor units through a small hole that is drilled in the wall of the building. The main advantages of split air conditioners are their small size and flexibility for zoning, heating, or cooling individual rooms. Some split air conditioners can have as many as four indoor, air handling units (for four zones or rooms) connected to one outdoor unit. The number depends on the amount of heating or cooling required for each building or zone (also affected by how well the building is insulated). Since each of the split air conditioner zones or rooms will have an individual thermostat, only that area where someone is present needs to be conditioned, saving energy and money.

4. How does a mini split air conditioner work?

Evaporative cooling systems operate by a simple method of drawing a large amount of air through a water-saturated membrane. The resultant underlying heat exchange produces a beneficial temperature fall of up to 59°F (15°C) in dry air settings. It is worth remembering that evaporative cooling systems are not suitable for use in humidity controlled environments.

                                                            

                                                                   

Simple Illustration of a Split System                           Setup of Indoor and Outdoor Units