If you have one, the HVAC system ( Heating, Ventilation, Air Conditioning), is probably one of the more important systems within your home. A good AC system will keep your home warm in the winter, cool in the summer, stabilise moisture levels in the air and remove impurities such as pollutants and fungal spores.
Generally AC repairs require a professionally qualified person, but there are certain jobs well within the capability of the ordinary householder. Keeping on top of these tasks will reduce wear and tear on your system and reduce expenditure when the time comes to call in the professional on the regular maintenance visit or breakdown.
There are big differences between residential and commercial AC systems. Residential systems are used in the private home and in small business premises, whereas commercial systems are used in large office blocks, large retail outlets, hospitals and other large buildings. Basically, the main difference is one of scale and purpose. Although both types are responsible for heating, ventilation and cooling, the domestic type uses less power, is smaller and less complex. In this article we will be discussing exclusively the residential type.
The Residential AC
A residential AC system is usually located on the side of the house or in the garden, somewhere easily accessible for maintenance and for venting.
A typical residential AC system comprises air filter, condenser, condenser fan, compressor, evaporator and drain. The component parts are divided between locations inside and outside the house and are usually chosen for the size of the house and quality of air conditioning. If this changes then a complete new system will be required.
What if you haven’t already installed a AC system?
Most new homes come complete with AC systems but older homes do not. In some parts of the world this results in stifling indoor heat and humidity in the summer or cold dry air in the winter. These houses can be retro-fitted with suitable systems. The price to install a new system depends on the type chosen, its ability to cool or heat the building and the price to have it installed professionally.
The different types of domestic AC systems are as follows:
Window. A window unit is probably the cheapest system you can buy. Units do not require any ducting and can usually be installed by a DIY enthusiast using the kit supplied with the unit. Although these types have a low cost and are easy to install, they are unsightly and block window light.
Central. A central air conditioning unit delivers conditioned air through underfloor and above ceiling hidden ducts from an external condenser compressor unit. It cools or warms the entire house simultaneously by delivering air to all rooms. This unit must be installed by a professional installer together with an electrical contractor. This type is probably the most efficient and has components hidden out of sight, usually outside, or can be on the roof or in the attic. This type is also the most expensive and causes most upheaval to the living areas when retrofitted. For this reason it is usually only fitted in new homes. The ductwork may leak if not checked periodically resulting in higher energy costs. Central air conditioners will improve the air quality as well as the temperature because of the central air filtration system.
Ductless. Ductless air conditioning systems are installed in houses that were built originally without a central air-conditioning system. They require a professional installation and an electrical contractor. The equipment is unobtrusive, does not use ducts and each room will have its own controls and thermostat which can be set independently of each other. They can be used to cool or warm some rooms more than others or in rooms that are not used continuously they can be used to just provide a gentle background temperature. Because each unit is independent no air is lost along leaky ducts. Ductless air conditioning units have the added advantage of being less noisy than central ones. They may require the electrical ring-main to be upgraded to suit the additional electrical load.
A new air conditioning unit will require regular annual maintenance visits to ensure it operates efficiently and to minimise wear. They can be an expensive purchase for the normal home owner but are a necessity in some of the regions that have extremes of temperature. For this reason, sometimes energy subsidies are available to help with the cost, but manufacture and installation of the equipment must always comply with local regulations laid down and enforced by local or national government.
AC units work by using condenser and evaporator coils to transfer heat between the inside of your house and the outside world depending on whether you want your home to be warmed or cooled. You will be able to set the temperature to the desired level using thermostats. Most equipment will also be able to adjust the humidity and some models will remove dust and pollutants too. The condenser and evaporator coils together with the refrigerant are therefore crucial to the smooth and efficient running of the system and must be properly maintained for the unit to do its job.
What Is Involved in AC repair and Maintenance
Maintaining your existing AC unit will ensure that it is ready to properly heat or cool or otherwise condition the air in your home all year round. Keeping the unit in good working order is also a sensible precaution against expensive breakdown visits. Lack of maintenance of a AC unit will shorten its life by 10 to 15 years and produce a 5 to 10% loss in efficiency thus increasing energy costs. It is recommended to have a maintenance programme carried out by a qualified and licensed technician at least annually and better to have it done twice a year. Having the work done in the spring allows the technician to check for any damage caused during the winter months and ensures it is ready for the heat of the summer. If the second visit is timed for the autumn then the unit will be in top condition before the winter arrives. Keeping to this bi-annual routine will keep your AC running at its most efficient.
HVAC installation and maintenance companies will provide annual preventative maintenance contracts for the householder. Some companies maintain only commercial or residential units and some companies maintain both, so when you contact the company be sure to ask if they maintain your specific residential unit.
The following tasks can be done quite easily by the householder and should be done regularly to prevent unnecessary damage to your AC.
Air filter replacement. Air filters remove dust particles from the air. If they become blocked, your unit will work at a lower efficiency and will become damaged. It is wise to check the filters yourself on a monthly basis. If the unit is running continuously then you may need to replace the filters every month to keep it running properly. Depending on the type of filter installed, you may be able to simply clean the filter rather than replace.
Coil cleaning. If the condenser and evaporator coils are dirty, then they cannot transfer the heat efficiently and will need cleaning. If the coils have been damaged then they will require replacing by the technician.
Coil fins. The coil fins will need combing occasionally to restore their shape to the original profile thus removing bends making it easier to release warm air.
Clean the surrounding area. As the AC unit will usually be outside in the garden, it is important to ensure the air vents have not become clogged with leaves and other greenery. Trim back shrubs that have grown too close to the unit and check that no animal nests are interfering with the free passage of air. In preparation for the winter, turn off the HVAC and hose it with water to remove any debris. Only do this when there is no risk of a freeze.
Clean drains. Clogged drain outlets will prevent the free draining of condensed atmospheric moisture. This will cause humidity and water damage in your home. Ensure these drains are clear of debris.
Lubrication. All moving parts will require lubrication to reduce friction. Well lubricated parts will reduce the amount of electricity used and lengthen the lifespan of the parts.
Electrical connection. All electrical connections can become loose through vibration caused by the normal running of the unit. Loose electrical contacts can become a fire hazard and cause the unit to malfunction. If you aren’t confident to do this yourself then use a qualified electrician or your AC technician.
Insulate exposed pipes. Check all exposed pipes have adequate and intact foam insulation.
Fit a cover. Fit a weatherproof cover to the unit.
These additional checks will be done by the technician:
Thermostat setting. The thermostat, located in the house must be set at the correct temperature to allow your unit to start and stop if the air becomes too warm or cold and to maintain the room temperature at the optimum range. If the settings are not correctly programmed, the temperature and humidity can cause discomfort and produce high electricity consumption.
Check refrigerant levels. Your unit may have developed a leak in which case the refrigerant level may be low. If the level is below the recommended level, the unit cannot work properly. It doesn’t cost a lot to refill the refrigerant, but there may be a leak which requires repairing, otherwise the fluid will continue to be lost.
Check seals into the home. Gaps in the seals where the ducts or pipes enter your home can cause problems and must be resolved for the unit to maintain the required temperature and humidity.
Check capacitors. Capacitors are used to start the system when the temperature deviates from the optimum. Check and replace these if required.
Check compressor. Some problems which may on the surface seem connected to a faulty compressor are often not. Checking that the compressor works properly can determine whether this is the case.
Electrical connections. Vibration and corrosion can cause electrical connections to become loose resulting in your unit either not working properly or not starting at all.
Residential and commercial AC systems require different expertise to repair and install so usually a AC company will only specialise in one type. Only the larger companies will repair both.
A maintenance contract will cover either one or two visits per year in which certain maintenance tasks are performed (depending on the time of year) and your unit will be checked to see if any component is nearing the end of its life or is damaged. Having a maintenance contract will give you more warrantee cover and usually give you a discount on all parts compared to a single call out when a repair is needed. It also means that if anything goes wrong with your equipment between visits, a technician will come to fix the problem straight away, usually for no extra labour charge.
AC Repair Contractors
Guarantees & warrantees
You will always get a guarantee and warrantee from a reputable repair contractor. Annual maintenance contracts provide the stability of continuity for contractors as they know that only their qualified technicians will be touching the equipment. It is usual for AC repair companies to have separate warrantees for labour and equipment parts. Labour warrantees give cover for up to ten years while equipment parts are usually covered for one year.
Choosing a contractor who offers good service at a fair price in the USA
Because a AC contractor is dealing with equipment that if faulty can leak and discharge substances that could potentially harm the environment, the technician is required to have certain certifications and qualifications.
AC technicians are required to hold a license. The recognised qualifications in the USA are The North American Technician Excellence certificate. (NATE). This qualification is recognised throughout the USA and is proof of the AC and refrigeration technician’s competence and knowledge. However, holding the NATE certificate does not legally entitle a technician to work in that industry. For this the technician needs to be certified. While there are some US states for which certification is not mandatory, all states recognise certification as a way of showing the technician’s competencies.
The HVAC Excellence scheme is designed to improve the competency of AC and refrigeration technicians by validating the technical education system both in the classroom and by ‘on the job’ training. It sets the educational standards and verifies that the required quality of learning has been met. There are always improvements in methods and equipment in this industry and HVAC Excellence ensures that CPD (Continuous Professional Development) takes place by providing courses and information to the industry. Most importantly they provide courses and credentials for instructors and trainers working in the field.
EPA 608 Certificate
The US Environmental Protection Agency mandates a national certification for any person working with refrigerant recycling and recovery. This is the EPA 608 certification which requires that all persons servicing or maintaining equipment that contain refrigerants or who dispose of equipment that could release refrigerants must attend a course and be certified by an EPA approved organisation. This educational course covers ozone depletion, CFCs, leak repair requirements and other rules to comply with environmental law.
Who to choose to look after our AC system in the UK
In the UK, the Institute of Refrigeration (IOR) is the professional body that oversees quality and certification in the industry. The IOR provides support for engineers and technicians who work in the refrigeration, air conditioning and heat pump industries. It is affiliated to the Engineering Council of UK and members can apply to join the ECUK as a chartered engineer, incorporated engineer or engineering technician. Engineering Council registration is a nationally recognised qualification showing the necessary skills and status, but in itself it does not provide legal certification. In the UK and Europe, the EU requires technicians and engineers who work on AC and refrigeration systems containing fluorinated greenhouse gases (CFCs) to be fully trained and registered. The engineers and technicians employed by a company must hold personal qualifications and the company must hold a Company Fluorine gas certificate. The company certificate must be issued by one of the following organisations:
- Bureau Veritas
The certificate provides evidence of company handling, storage and disposal procedures for fluorine refrigerants. The company certificate must be renewed every three years.
The personal qualifications are known as the SRAC certificates (Stationary refrigeration and air conditioning systems). These also include heat pumps. A person needs these certificates to not only:
- Install new systems.
- Service systems.
- Maintain and repair.
- Recover and recycle refrigerant gases.
- Decommission old systems.
But also to work on refrigeration units held in trucks over 3.5 tonnes or trailers made to be towed by trucks.
The SRAC qualification must be one of four categories:
Category 1. Qualified to do all activities.
Category 2. Qualified to install, service, maintain and recover refrigerant gases from systems of less than 5 tonnes carbon dioxide equivalent.
Category 3. Qualified to recover refrigeration gases from systems holding less than 3kg fluorine gas.
Category 4. Qualified to check systems for leaks without breaking into the refrigeration circuit.
Additionally you must have one of the qualifications listed from an accredited provider:
- City & Guilds Building Services Industry. – Qualifications relevant to refrigeration of air conditioning.
- Building Engineering Services Association. – Refrigeration assessments chosen from the appropriate category.
- LOGIC Certification Ltd. – Fluorine gas qualifications chosen from the appropriate categories.
- Any equivalent qualification recognised by an EU state.
Who should you NOT choose?
Your air conditioning system is an expensive suite of equipment that contains potentially toxic substances. You don’t want just anyone tinkering with it. There are certain jobs suitable for the householder and unskilled person but the vast majority of maintenance and installation work must be done by a licensed and skilled operative. Therefore always make sure that yourVAC technician is properly licensed and trained.
AC Repair Cost
The cost of maintenance of your AC unit can work out to be an expensive payment. It is for this reason that most maintenance companies will offer you a payment plan so you can make monthly payments throughout the year. You may also get discounts on the price of any parts needed.
|Installing types of A/C System (labour only)||Minimum||Maximum
|Plus cost of parts dependent on size of home||
|Flat fee for one maintenance visit||$70||$100
|Single Maintenance Visit (2 hrs) additional to flat fee||$50||$150
|Annual Maintenance contract||$100||$150
|Technician labour (per hour)||$50||$70
|Plus cost of parts
|Replace & refill Refrigerant liquid||$100
|Repair Refrigerant Leak||$300||$1000
DIY vs Professional. Which is Best?
As stated earlier, a ‘Window’ AC system can be installed by the amateur, with some help from skilled specialists like glass cutters and electricians. However, in all other AC systems there are certain jobs which you can do and certain jobs that you need to be licensed and trained to safely do. Unfortunately AC installation and repair is not one of those jobs where it is permissible to ‘do it yourself’. By all means, do the basic preventative maintenance job discussed earlier, but leave the skilled work to the professionals.
10 Questions to Ask the Contractor Before Hiring
Are you certified?
Although some US states do not require AC technicians to be certified, it is always advisable to choose one who is. And, of course, if you live in a place where certification is compulsory, then you have no choice. If you live in the UK or Europe, your technician will need the certifications mentioned earlier.
What qualifications do you have?
Ask if the technician has followed an approved EPA course of training. Ensure that there is at least one person working on your equipment who holds the appropriate credentials and certificates. The UK and Europe require personal qualifications to work on air condition and refrigeration systems as well and have been previously mentioned.
How long have you been in business?
Ask the technician or manager of the AC repair company how long they have been trading. It is always better to use someone with experience.
When can you begin the job?
If you have a breakdown, then you want the technician to start work as soon as possible. If the required work is for planned maintenance then it is acceptable for work to start and finish any time before the heat of summer or the cold of winter arrives. Obviously if you have a maintenance contract with the HVAC company then you will have a regular time of year for your equipment to be serviced.
How long will the job take?
Once again, if you have a maintenance contract then you will be paying the same amount no matter how long the job takes. As long as the job is done well and to specification then it doesn’t really matter.
Do you foresee any major problems?
Unless you have a major breakdown, the technician should know which parts are reaching the end of their useful life and require replacing.
Can I have a firm quote?
Always find out the maximum you will be asked to pay.
Have you any references from previous customers?
If you haven’t used a company before, then it is always a good idea to ask them for a list of satisfied customers. Get in touch with the customers and find out the technician’s reliability and level of skill.
What is your ‘after sales service’?
It is always a good idea to enter into a maintenance contract. If you have a breakdown or malfunction, usually a technician will be on the job within hours of contacting them. Find out what warrantees and guarantees the company provides on labour and parts.
What will he expect of you?
Always a tricky one to answer as some householders will know how to do the preventative maintenance work and others will not. Ask the technician how you can make the visit easier. At the very least make sure that vents are not obstructed by vegetation and debris.
Car AC Repair
Air conditioning in the car works in exactly the same way as air-conditioning in a house or office block. The only real difference is one of scale.
Why air con in the car?
It isn’t always best to open the window to keep the car interior cool in hot weather. If you live in a hot, dusty and arid country, then you want cool air without letting in dust and grit. If you are in a hot, humid country then you want cool, dry air. If you live in any temperature climate and live in a city then you want to have cool air without the pollutants emitted from the other vehicles on the road. Your car’s air-con isn’t only useful in the warmer months. In winter, it is often a case that you have a misted windscreen when you first turn on the engine. No problem, just turn on the air-con for a blast of warm dry air, your glass will soon be clear. It is also a good idea anyway to turn the system on occasionally in the winter, to make sure things don’t seize up.
Open the car window or use the air-con?
If you are travelling fast and want cool air, do you open the window or turn on the air-con? The answer depends on whether you are ok with using more fuel or if you are ok with excessive noise in the cab. At high speeds with the window open, you have excessive noise, a blast of uncontrolled air and a loss in aerodynamic profile of the car which uses unnecessary fuel. The compressor, the part that makes the air-con do its job requires energy and it gets that from the fuel. So if all you want is a cool car then for best fuel efficiency use the air-con at high speeds and open the window at low speeds.
Isn’t the car air-con covered in its service or its roadworthy test?
In a lot of countries, all cars over three years old have to undergo an annual safety check to ensure the car is safe to drive on the public road. The inspector has a list of items to check and must not deviate from them. Unfortunately air-con is a luxury and not classed as an essential so it won’t get looked at. Similarly, the manufacturer schedules items within the standard service for the mechanic to check and replace to ensure the car keeps running at its optimum, so it won’t get looked at during the standard service either. Manufacturers do however provide a separate air conditioning service to ensure the air-con keeps running at its optimum. This re-gas is recommended to take place every two years. So unless you have a new car and the manufacturer has specified an air-con check, it will be up to you to get it done yourself.
What happens when the air – con stops working?
The refrigerant gas in your car’s air-con is crucial to the system working properly. With the gas continually being condensed, pumped and evaporated, you are bound to lose some. After a while, the air-con refrigerant level drops until there isn’t enough in the system to do the job. That is when you need to refill the reservoir to keep it working in optimum condition.
Don’t forget that if your air-con has stopped working properly it may be something else, but it most likely just needs a top up of refrigerant. If the air con is still blowing warm air after that then it most likely is a crack in a hose somewhere causing the gas to escape. This will obviously need repair otherwise you will continue to lose refrigerant.
How is the refrigerant recharged?
Recharging the air con system requires all traces of the old refrigerant and any trace of moisture to be removed from the system. Not really a job you can do yourself. Don’t worry, there are many specialist car repair garages that have the equipment to do this kind of job and these days the work is carried out automatically by a special machine.
The sequence of tasks is as follows:
- Connect one hose from the air-con service machine to the high pressure port.
- Connect one hose from the air-con service machine to the low pressure port.
- Carry out pressure test to check the system’s integrity and find out how much gas has been lost.
If there is little or no gas in the system then there is a leak.
- Find leak and rectify.
- Remove traces of refrigerant and other impurities from system using vacuum pump.
- Inject fresh refrigerant.
How long does a refrigerant re-charge take?
If there are no other problems with the system, removing the old gas and refilling with fresh takes about 45 minutes.
How often between re-charges?
Most vehicle manufacturers recommend that a refrigerant re-charge should be done every two years whether you use the air-con a lot or not.
What other easily remedied problems are there?
Apart from loss of refrigerant gas, the other most common problem with car air-cons is growth of bacteria and fungus around the evaporator. The conditions in the evaporator are perfect for the growth of certain kinds of bacteria, fungi and mould. This can produce a smell not unlike old sweaty socks and can be very unpleasant.
What is even worse is that the spores and bacteria can be blown into the passenger compartment and cause illnesses and breathing problems. The solution to this is a separate de-bug treatment which will decontaminate the whole system. It will be available from the same place as your air-con refrigerant top-up.
Can you do car AC repair by yourself?
Although DIY top up kits are available, it is not wise to attempt this car AC repair job yourself as you may have the problem of a leaky unit which needs repair or replacement and which releases refrigerant to the atmosphere (At the time of writing and since 1996 the refrigerant is R134a, previous to then it was a CFC which has now been banned).
Auto AC repair is not a job for the amateur and is preferably done by a professional car repair garage that has the specialist equipment. Not only that, but the inadvertent release of the air-con refrigerant can damage the environment. Even though, on average the cost of a DIY kit is only about $20, the product may not help your unit at all and may even cause damage.
Air conditioning systems are expensive to buy and install and you need to have them looked after in the best possible way. Choose a reputable company with certified and trained technicians and once you are happy with them, take out a maintenance contract. It will be the less expensive option in the long term. Ask the HVAC repair company what tasks it is permissible for you to do yourself on a regular basis to prolong the life of the equipment, save you money and make the technician’life easier. Follow up on references to find out the contractor’s level of reliability and skill and check the technician’s certification and qualifications before allowing him anywhere near your equipment. Check that the labour and replacement parts have guarantees and warrantees. Most importantly check the qualifications and certifications of the technicians and the company and remember that these may need to be renewed so check their expiry date.