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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Maintaining your air conditioning unit

While most commercial and domestic establishments in the UK invest in air-conditioning systems in order to tackle the temperate climatic conditions, not many give due importance to preventive maintenance programs. Getting into a routine maintenance program for your aircon comes with good reason, the most significant benefit being saving in power expenses over the lifespan of the unit. In this article, let us look at why maintenance is a necessity and what activities go into ensuring an efficient and well-rounded maintenance cycle.

Why is Preventive Maintenance Important?

Routine maintenance can help maintain and uphold operational efficiency levels of your aircon unit to its original levels at the time of purchase and installation. Aside from this, preventive measures also ensure:

  • Better energy efficiency by clearing out clogged filters and condenser coils. These impurities seep more energy for the aircon to function, contributing to the rise in your electricity bill

  • Increase in the lifespan of your aircon unit by way of regular servicing and maintenance

  • Elimination of health risks that are associated with poor air quality

  • Low repair and replacements costs as any malfunctions or faulty parts are identified at early stages during maintenance cycles and fixed immediately reducing stress on other components which can otherwise increase your replacement costs

  • Through regular maintenance and early identification of any possible malfunction, replacements can often be done under the warranty period, resulting of little or no outlay from the user’s end

  • Lesser emergency repairs and sudden breakdowns in periods of heavy usage making sure your aircon system doesn’t let you down when you need it the most

What Constitutes a Comprehensive Maintenance System?

An aircon unit’s filters, coils and fins require regular attention and cleaning in order to reduce the load on power consumption and supply clean fresh air to the establishment. This is particularly important if the unit is installed in factories or commercial establishments that are prone to dust and debris. It strongly advisable to engage a service provider to check your unit on a monthly basis making sure it is operating efficiently by focusing on the following areas:

  • Air Conditioner Filters: Clogged and dusty filters block normal airflow denting the efficiency of the system significantly and blocking normal airflow. This, in turn, increases the stress on the evaporator coil and its ability to absorb heat. While some filters are reusable, some other require regular replacement every few months. It is advisable to run this task every month or two, more so if you have any furry pets at home or have installed the unit in a dust prone area.

  • Air Conditioner Coils: The evaporator coils and condenser coils collect dust over the period of its runtime thereby insulating the coil and its ability to absorb heat. These coils require your attention every 8-12 months for efficient functioning

  • Clogged Drains:It makes good sense to run a stiff wire down your aircon unit’s drain channels as clogged drains prevent efficient humidity control which may discolour walls and carpets in a domestic establishment due to water leaks and moisture collection and may dampen metal equipment in a factory set up over time. Conduct this exercise once every six months and more in rainy and humid weather conditions

  • Aluminium Fins: Over time, the aluminium fins on the condenser coils bend and block the air flow. Good news is that these fins can easily be brought back to shape through a service routine that includes a tool called the fin bomb that is retailed by many aircon wholesalers. A good practice is to make sure no smoking areas are situated around the unit to prevent any damage to the fins

  • Thermostat Control: Never run your thermostat on a colder setting just to cool your room sooner. This is a myth and it simply won’t cool your room any faster; it will only increase your power consumption

  • Window Seals: At the start of every heavy usage season, inspect the seal between the aircon and the window frame to make sure it is in contact with the unit’s metal case. Poor contact can result in seepage of cool air from the system to the outside environment

  • Inverter Driven units: Always make sure you invest in inverter driven units as opposed to conventional units that work on 100% capacity and power usage at all times. Inverter-driven units start incrementally and when the room reaches the desired temperature, they slowly reduce power consumption levels to merely maintain temperatures.

A good power saving practice would be to install ceiling fans that operate in a counterclockwise direction that facilitate the upward movement of hot air accumulated in a room. Industry experts also recommend covering the exterior unit of your air-conditioner in months of non-usage in order to prevent external factors such as fallen leaves, snow and other debris to clog or harm it. Other specialised maintenance activities that service engineers can execute for you include:

  • Inspecting the overall system for correct functioning

  • Checking moving parts for wear and tare

  • Checking and adjusting gas pressures and possible gas leaks

  • Inspecting pipe works and other connections within the aircon

  • Cleaning and adjusting the thermostat

  • Provide a refill for any lubrication agents required in the system

It is strongly advisable to engage the professional services of maintenance engineers in order to ensure your appliance is at its optimal functioning capacity. They are also aware of any statutory and regulatory requirements with regard to aircon systems in the UK and ensure you are compliant. For example, the recent revision in the F-gas legislation that has come into effect from 1st January 2015 has held the owner/operator of the aircon equipment legally responsible to have their aircon systems checked at least once a year in order to avoid environmental hazards if they fall under the category of a certain level of gas leak.

We are Subcooled would be glad to partner with you for all your air conditioning maintenance and service requirements. Get in touch with us today and places all your aircon concerns in our able hands.

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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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How Your Aircon Can Help With Air Quality

While we have little control over air quality outdoors, the quality of the air we breathe within the four walls of our home is a strong determinant of the effort we invest into maintaining good air quality, cleanliness, and efficient HVAC systems. If you are one of the many who suffers from seasonal allergies that bring with them sneezing, itchy eyes, congestion, and flu, your air conditioner can help provide you relief to a large extent.

We spend a minimum of 12 hours in our humble abodes on any given day and this metric only increases for children, homemakers, and professionals with flexible work hours. With activities such as gardening, lawn mowing and garage & car maintenance surrounding our houses, we churn a lot of dust and move it from one place to another. Fibre from synthetic carpets, furniture fabrics and drapes can also play havoc.

Fragrances and volatile elements from personal care products and cleaning agents can prove to be troublesome. Hence, it is imperative that proper attention is given to air quality. We are here to help you understand how your aircon can help you iron out these concerns and the steps you should take in making your unit is doing its best to provide you with good air quality.

Air Moisture

With the temperate climate in the UK, we experience a spike in the humidity levels in the air from time to time. This moisture serves are a breeding ground for mites, allergies and bacteria, mildew and molds. An air conditioner that is fitted with a dehumidifier can help in removing moisture in the air, providing you with clean fresh air to breathe and locking out air irritants and pollutants. If you have a dense garden or flora cover around your home which calls for regular watering, it is best you invest in a dehumidifier to avoid airborne bacteria.

Dust & Pet Dander

If the area surrounding your home is dust-prone or the activities of your children or family often result in them bringing dust and mud and germs into your home such as football games, running etc., you will have to tackle the problem of air quality all year round. The presence of pets at home too brings in excess dust and debris as well as the problem of fur shedding and the occasional sudden nature’s call indoors. In such an event, your aircon can help you breathe easier. A good air conditioner with a strong filter can filter out aggravating or troublesome air particles as well as bacteria to give you and your loved ones fresh and clean air to breathe. Renovation or carpentry repairs also cause an upheaval of dust which your aircon can help you ward off.

 Help Your Air Conditioner Help You

You can wave goodbye to air quality issues if you take good care of your aircon.

Some best practices listed below will make sure your AC unit is well equipped to beat the dust:

         Air Filters – Your main weapon against poor air quality is a good filter. All air filters are assigned a MERV rating or Minimum Efficiency Reporting Value rating which depicts the ability of the filter to remove particles from the air. A value of around 8 would indicate an efficient filter for dust prone areas. Electrostatic filters are also a good option for allergy prone aircon users as they attract airborne particles using electric charge thereby cleaning the air effectively.

         Clean Away Dust & Debris on Outer Unit – Your AC’s efficiency depends on the ability of the outer unit to access air from the external environment and condition this air to suit your needs indoors. A clogged outer unit covered with dust, debris, leaves and twigs will result in dirty air being used by your aircon, leading to compromised air quality and increased strain on your unit. Hence, regularly clear off any build up on your unit and keep the surrounding areas also clean.

         Dust Your Aircon Vents – Many of us are investing heavily in dusting and vacuuming agents but often times do not give due attention to aircon registers, vents, and fittings from a cleaning perspective. Develop a habit of cleaning your air conditioners external fittings on a weekly basis with a dry cloth/tissue to prevent dust clogging the air outlet.

         Check Your Ductwork – Avoids any drips or leakages on your evaporator coils, drain pans and air handlers to eliminate any scope of fungus or mold breeding as well as corrosion of the metal particles involved by regularly checking your ducts.

         Pay Attention to Air Circulation – Improper circulation of air can lead to an air-conditioned home that is highly infected with mites and bacteria. This can be attributed to a poor choice of location to install the aircon which results in what is called a cold spot – an area where the air-conditioned air fails to reach in the designated space or room. These cold spots breed mites and also give rise to allergen and fungus, which can quickly spread to the rest of your home too. Hence it is imperative that due attention is paid to efficient design and installation of air conditioners.

         Invest in a Maintenance Cycle – We can’t stress on this enough. This is an absolute must to maintain your entire aircon ecosystem from an air quality perspective as well as energy efficiency and wear and tear perspective. We at Subcooled provide comprehensive service packages to make sure all aspects of your aircon are taken care and your unit operates efficiently for years.

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Commmercial high level air conditioning amazon

Subcooled Air Conditioning have recently started a huge Air Conditioning and ventilation project at the new Amazon depot in Tilbury. Every aspect of the the trade will be covered in this installation, from high installation standards while working at height.

Using cable tray brackets with Hilti rod hangers, the labour saving hugely outweighs the additional material costs which when working at these heights is a ‘no brainer’.

  1. While conducting our annual time and motion study, moving round this huge site on these MEWP’S, not only saves time and energy from building and climbing  scaffold towers, it minimises our employees working at height risks. At Subcooled Air Conditioning health and safety is paramount to our working environment. With our 100% un-tarnished safety record, we strive to be incident and accident free.


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Good looking air conditioning

Air conditioning no longer has to be aesthetically intrusive. Mitsubishi, Daikin, LG, Samsung and other major brands are concentrating on domestic users and there tastes.

New colours, shapes and style air conditioning units are flying off the shelves, giving end users plenty of eye candy when choosing there system.

From the Mitsubishi Zen unit to the new Samsung AF9000, your literally spoilt for choice this summer. Call Subcooled Air Conditioning for more information on 01296770482 or check out our photo gallery at


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Air conditioning Hemel Hempstead

Subcooled Air Conditioning provide air conditioning, ventilation and building services across Buckinghamshire, Oxfordshire, Hertfordshire and London.  New installations, servicing and maintaintenance contracts are available in all aspects of our industry. We can take your project from design through to completion, or simply manage your existing building services. We are experts in all building services including close control air conditioning, chilled water air conditioning and VRV VRF air conditioning systems. Subcooled are able to solve problems with current systems, keeping your staff and tenants comfortable whatever the weather.

Call Subcooled for a no obligation quotation.

Contact Us Today

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