Setting the Thermostat

Setting the thermostat correctly is critical to achieving comfort and minimising energy use. Setting the Temperature one degree cooler than needed in the summer will cause a surprisingly large increase in energy use. Similarly setting the Temperature one degree warmer than needed in the winter will also cause a surprisingly large increase in energy use. Normally it is best to set the temperature at 22 degrees. For most air conditioners this would give a temperature of around 24 degrees for most of the summer and 20 degrees for most of the winter. However in practice there are a number of factors that may require a different setting. For example if in winter you get cold air next to the windows sinking down and pooling at floor level, it may be necessary to set the thermostat at a higher temperature.

Often thermostats are not very accurate; this is not really a problem if you can find a single setting that achieves comfort all year round. Sometimes though, it is necessary to occasionally tweak the setting.

To find the ideal thermostat setting,
1. Choose a day that is warm or cool, but not an extremely hot or cold day.
2. Ensure the air conditioner has been running for at least one hour.
3. Initially set the thermostat to 22 degrees.
4. Wait for a period of time (at least 10-15 minutes) to see how the air conditioner behaves
5. If this hasn't achieved comfort, set the thermostat slightly higher (or lower as seems appropriate). Don't adjust it by more than a degree at a time or you will end up overcorrecting and take longer to find the best setting.

Remember there are some problems that can't be fixed by adjusting the thermostat. For example, if the air conditioner doesn't have enough capacity due to the temperature of the day, adjusting the set point won't make any difference to the room temperature. If this is the case, read the sections on 'Cleaning Filters', 'Maintenance Requirements', 'Shading Windows', and 'Insulation'. Setting the thermostat also can't generally cure hot and cold spots, (refer Hot and Cold Spots).
If it is impossible to find a suitable setting, phone Clive Blanchard, to see how the problem can be rectified.

Cleaning Filters

Filters require cleaning or replacement (depending on the type) because as they accumulate dirt, they block up, reducing airflow and hence the cooling capacity of the air conditioner. In addition some types lose filtration efficiency as they get dirty.

There are a large number of different types of filter with different requirements. If you have a proper maintenance manual for the installation, refer to the manual for cleaning advice. If you don't have a proper manual, the main types and their normal cleaning requirements are as follows: (If you are unsure speak to your contractor or phone Clive Blanchard, Consulting Mechanical Engineer). In some cases more frequent cleaning may be required.

Return air grille filters: these filters are generally in hinged filter frames attached to the return air grille. These filters are really residential filters, unless they are used in conjunction with another higher efficiency filter or air cleaner. These filters are generally of the washable type and should be cleaned by gently washing with water. If they won't clean, use a mild detergent. These filters usually require very frequent cleaning, at least monthly, and often more frequently.

Deep bed filters: These are large filters usually 400 to 600 mm deep. These may be of the washable or disposable kind. The life of these varies depending on the design and the amount of dust they are subject to. In general you should get at least 12 months life, and sometimes up to three years life between cleanings or replacement. It is generally better to get your air conditioning service company to service these.

Electronic Air Cleaners: These may be stand alone units or incorporated into the ductwork. The cores generally require cleaning approximately once per month.
Other types of air cleaner: There are a number of other types of cleaner. Refer to the manufacturer's literature for details of maintenance requirements.

Choosing an air conditioning system

When choosing an air conditioning system, the following are the main criteria to consider
· Comfort of your staff
· Ventilation to avoid stuffiness, meet current expectations and to meet legal requirements.
· Purchase cost
· Running costs
· Reliability
Confidence in the contractor

If you want to e-mail us: lloydac@fedderslloyd.com

Disclaimer:

The advice contained in this website is of necessity of a general nature and only addresses the most common items. It is up to the user of the information to ascertain its suitability for their particular case, and to seek specific professional advice if necessary.