General Airconditioning Principles

Keep cool this summer! Get a good quality of air conditioner for home and office. Make this summer the one you will always remember with people you will never forget. But before making a choice you should go through the guidelines to make you aware of the facts and figures regarding air conditioners:


On a hot summer day, there are few appliances which are life-saving. Air Conditioners are one of such devices. AC’s are the miracle of engineering that pumps heat from one side to another, shifting the heat to the outside and circulating wonderful cool air inside. And they do this in a remarkably small space, often without having to knock holes in your walls. So, how do these miracles of cool work? Fundamentally, a window AC unit is a pump, one that shifts heat instead of water. It does this by using a chemical that turns from a liquid into a gas with a relatively small shift in pressure. Called a phase transition, this process is at the heart of how AC units work.


When the pump is active (which you can usually hear; it’s the low-frequency rumble from a working AC), it’s compressing the coolant so it becomes a liquid. This liquid passes through the outside radiator, where it sheds heat into the outside air. When it reaches the expansion valve, only a small amount is let through, so the pressure on the other side is much lower. This makes the coolant evaporate, which cools it down. From there, it passes through the inside radiator, and the air passing over this is cooled. The coolant absorbs the energy (the heat) from the air inside the room, cooling it. The coolant then moves into the pump, where it is compressed again and pushed into the outside half of the loop, and the process repeats. The whole process is controlled by a computer that measures the temperature of the air being sucked into the unit and turns the pump on and off as required. Because the coolant takes time to pass through the expansion valve, the pump doesn’t run all the time when the unit is cooling: when the pressure on the hot, outside part of the loop reaches a certain level, the controller turns the pump off until the pressure falls. As the coolant passes through the pressure valve, it evaporates and cools in the inside radiator, and you feel the cool air. That’s why you don’t feel an immediate rush of cool air when you turn on a window AC unit: the pump has to build up the pressure before the cooling can begin.


Keep your air-conditioner (AC) maintained to save your money and time as well by doing simple maintenance steps you will also extend its lifespan, saving money on costly early replacement. An AC needs regular attention to be sure it’s operating at the highest efficiency.


Electricity and human contact doesn’t go well so always remember to switch off the power before carrying out any maintenance. The electricity should remain off until  you are done with the maintenance work


On the outdoor unit look for any unwanted materials such as debris or small plants and leaves and remove them carefully. You can also wash down the outdoor unit with a garden hose and spray water over the fins in order to remove accumulated dust and dirt.


Bent and mis-shape fins can obstruct the efficient movement of air. Make sure the fins are straight, for minor deformations you can carefully straighten them, but if you’re not sure please call us for advice first. Make sure the area around the outdoor unit is free from plant growth and there is unrestricted air-flow near the fan and fins.


On the interior side warm, humid air from your home’s atmosphere is blown through the evaporator coil. The cold coil absorbs heat from the air, cooling it before the air is circulated back into your home. The humidity in the air condenses on the cool surface of the evaporator coil as liquid water, dripping into a pan below. From the pan, the water flows into a drain tube which is typically routed into a basement floor drain, utility sink, or outdoors. Over time, algae and mold can build up and clog the drain, So if the water is not flowing or flowing freely the drain will need to be cleared. The drain is usually a one-inch PVC pipe (white, grey, or black). Follow it to the end where it drains. Often the line drains outside near the condenser unit. Once located, use a wet/dry vacuum to clear the drain.


The filter in your HVAC system should be changed at least twice a year – once just before the heating season begins and once before the cooling season begins. If you live in a particularly pollution prone area, you may want to change it more often. Always replace the filter with a new filter that has the same airflow rating.


Refrigerants make air conditioning possible. Contained within the coils of an air conditioner, these liquid agents cool and dehumidify indoor air. For years, the most common refrigerant gas used in air-conditioning was R22 freons. Today, the major brands have introduce new innovations due to consideration of environmental concerns. Production of systems using R-22 refrigerant is being phased out. Meanwhile, cooling systems have introduced an environmentally friendly alternative to R-22. EPA has recognized chlorine-free R410A refrigerant Because R-410A contains no chlorine, it is considered ozone-friendly. Highest efficiency cooling systems are designed to use R-410 A refrigerant, therefore providing an economic benefit in addition to the environmental benefit.  R-410A systems are also known for improved reliability, quieter operation, improved dehumidification, and enhanced heat pump performance.

The main Features of R-410A are :

·         R-410 A is a hydro-fluorocarbon ( HFC ) & doesn’t contribute to ozone depletion.

·         its operating pressures are 50% higher than R – 22

·         R410 requires components capable of working at these high pressures

·         It is the most common refrigerant for new light commercial unitary AC’s.


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Popular AirConditioning Myths Debunked

Come summer and every air-conditioner user has a list of to-dos and aircon trivia to share with a group of friends. Saving power consumption and maximising benefits is the ultimate aim of every user. Everything we hear and pass on, however, may not necessarily be true. So, we have put together a set of commonly shared aircon myths and burst some surprising misconceptions to make life simpler for you and your loved ones. Read on for some revelations!

Myth: The location of the air-conditioner doesn’t matter in the room as long as you have one

This couldn’t be more untrue. There are too many considerations that go into choosing the optimal installation location. Make sure the outdoor unit is not exposed to direct sunlight. That’s going to overwork your aircon and shorten its life. It’s best to not have any plants or shrubs around the outdoor unit lest they block airflow. Never install a thermostat close to any electrical appliances or lighting units. The heat emitted by these can cause inaccurate measurements of the room’s temperature by your aircon. Don’t set up your aircon facing the exit/doorway of the room. That’s unnecessary seepage of cool air every time the door opens. Windows are good solar heat collectors and hence its best to avoid directing your AC unit to a window and waste cool air on it. Trust us experts at Subcooled to guide you through the installation process

Myth: Maintenance is unnecessary expenditure and your aircon will work just fine without it

We cannot possibly stress how far from the truth this is. Invest in a good maintenance cycle with a service provider to eliminate dust and debris collection in your air conditioners vents that are going to reduce air quality and pull in more power. Any faulty part is only going to increase stress on other parts and generate a larger replacement bill when the aircon breaks down. Any wiring issues or wear and tear can pose as serious deterrents to cooling. We swear by preventive maintenance! Do you?

Myth: Set the lowest temperature to cool your room faster

Sorry guys, there’s no truth in this one. Tuning your thermostat to a lower temperature will get the power bills soaring higher and nothing else. Ideally, maintain a temperature of 21 degrees to 23 degrees for optimal comfort as well as low power results.

Myth: Get yourself the biggest possible air-conditioner you can afford for maximum results, irrespective of the room size

Not true at all. The thumb rule is to choose an air-conditioner that complements your windows and the directions they face, roof characteristics, room structure, air leakage, the direction of your doors, insulation and of course your budget. Remember, air conditioners don’t just cool the air, they also dehumidify it. Hence, the size of the machine is only limited to complementing the size of your room, and cannot be the single most important factor in achieving good results. Subcooled would love to help you figure out what’s best for you.

Myth: Air conditioners are only meant for summers

While this may have been true in the past, modern technology has given us the luxury of aircon units that have specialised modes for winters too. Hence, your aircon can be your buddy through all seasons. The monsoon mode helps seep out humidity from the air, while heat modes can warm up your room during winter months.

Myth: Spending too much time in an air-conditioned room can make you sick

Not true again. Common colds or fevers are caused by viruses and not by cold temperatures. If this were true, the entire population would be sick during winters due to exposure to low temperatures. While accumulated dust and mold in the vents can aggravate allergic symptoms, air-conditioned air certainly can’t make you sick no matter how much time you spend in the room. Keep the vents and filters of your aircon clean to ensure healthy clean air.

Myth: Leaving the ceiling fan on can keep your room cool

All a ceiling fan does is circulating the air in the room. While it makes the people in the room feel cooler due to the wind effect against their body and evaporation of sweat, it does not lower the temperature in the room at all. Turn off the fan the next time you step out of a room and watch your power consumption bill dip.

Myth: It is better to let an air conditioner run until it quits

Don’t make the mistake if running an air-conditioner that’s outlived itself. Slugging along your 10-12-year-old air conditioner is going to cost you more in terms of electricity consumption and repairs. You would rather invest in a new, more energy efficient machine with superior technology and watch your power bills drop.

Myth: It is more energy efficient to leave your AC running when you leave home than come back and re-cool your home again

While you’re away, it makes little sense to leave your aircon on and keep replacing cool air with more cool air repeatedly. Your unit and its compressor are going to be operational for 8-10 hours while you are away, and of course continue to be on when you’re back, leaving it with no downtime. It makes better sense to use a programmable thermostat and set a timer for your air-conditioner to turn on thirty minutes before you are home.

Now that we’ve got most of the myths out of the way, we hope we’ve cleared the air (pun intended) and helped you with your air-conditioning woes and doubts. One last tip to leave you with – turn off the main switch when your aircon is not operational. It definitely deserves a complete shutdown once in a while. For any concerns with your aircon, drop us a note and we’ll be glad to help. Happy cooling!

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