Ductless Air Conditioning and Heating Frequently Asked Questions
Ductless air conditioners and heat pumps are also called mini-splits, wall mounted splits, or duct-free systems with certain manufacturers or unitary air-source air conditioners and heat pumps for more technical jargon.
How does an air conditioner work?
An air conditioner works by transferring the heat from the indoor air to the outside and transferring the coldness from the outdoor air to the inside. Transferring the actual air would be highly inefficient, so air conditioners utilize a refrigerant along with components such as a compressor and expansion valve to get the maximum performance out of temperature differences between the inside and outside.
More information on how the refrigeration cycle works can be found at the following Wikipedia entries:
Air conditioners and vapour-compression refrigeration cycle
What is a heat pump?
A heat pump is an air conditioner that simply reverses the flow of refrigerant between the outdoor and indoor units. Please note that all heat pumps are also air conditioners. When heating is called, the heat from the outdoor air is absorbed by the outdoor unit, then more heat is added by the compressor then pumped into the indoor unit. After being ejected into the room, the colder refrigerant is pumped through an expansion valve causing the refrigerant to become very cold. That is why some heat pumps can still heat homes when it's -25°C outside!
More information can be found at the Wikipedia heat pump entry.
What are the main components of a ductless air conditioning system?
A ductless air conditioning system is quite simple and includes an outdoor unit, indoor unit(s), refrigerant line-sets, power and controls wires connecting them. The outdoor unit includes the condensing coil, the compressor, the expansion valve and a fan to get airflow through the condenser coil. The indoor unit includes the evaporator coil and a fan for airflow. The line-sets connecting the indoor and outdoor units are made up of heat insulated copper tubing for transferring the refrigerant.
Is there any air exchange between the indoor and outdoor units?
No, the line-sets flow only refrigerant between the indoor and outdoor units. The refrigerant used in all new systems is R-410A, with R-22 systems quickly being phased out.
Is a ductless air conditioner more efficient than a central air conditioner?
In most cases, yes. It is more efficient to pump dense concentrated liquid than it is for air. With ductless units the dense refrigerant is pumped to the evaporator which is placed close to the ceiling and since colder air is more dense than hot air, the cold air will naturally drop allowing the air conditioner to utilize its maximum cooling capacity.
Unlike central air conditioning systems, where the evaporator unit is placed in the basement above the furnace, which needs to push the cold dense air up to the second or third floor. In central systems most of the air will travel through the shortest runs creating a cold basement, a fairly cool 1st floor, and usually unsatisfactory conditions on the 2nd and 3rd floors.
What is SEER?
SEER is an abbreviation of Seasonal Energy Efficiency Rating. It is a measure of the seasonally adjusted cooling output of a unit divided by the energy consumed. The higher the SEER rating, the more energy efficient the unit. The minimum SEER rating for new air conditioners is 13 SEER.
SEER ratings have recently replaced EER ratings in popularity which are similar, but without the seasonal adjustment. EER ratings are usually lower than SEER ratings. More information can be found on Wikipedia's SEER entry.
What is HSPF?
HSPF is an abbreviation of Heating Seasonal Performance Factor. It is similar to a SEER rating in that it measures the heating output vs. the energy consumed by the unit, adjusted seasonally. More information can be found on Wikipedia's HSPF entry.
Is one ductless air conditioner able to cool the whole home?
Yes, if the indoor unit is properly placed such as at the top of the stair landing on the second floor, then the airflow can be adjusted to completely cool the 2nd floor and the remaining cool air travels down the stairs to the 1st floor. Through natural convection, the whole home can be cooled quickly. Hundreds of homes without ducts in Toronto have been cooled with only one unit! Usually only one 12,000 or 15,000 Btu/h unit is necessary.
Can ductless heat pumps be utilized in Toronto?
Definitely, the average minimum temperatures in Toronto for the months of January and February are approximately -7°C. Also the number of days in the year where the minimum temperatures are below -10°C is only around 26. These are also minimums, meaning the daytime highs are usually higher. By choosing the right system with a low ambient heating option, you will be able to heat your whole home with just the ductless heat pump for most of the long winter days.
With all that said, a primary (non-heat pump) heat source is highly recommended in Toronto and the rest of Canada such as in-floor heating, radiators, fireplaces or furnaces.
Can I still use my R-22 equipped ductless system?
Of course, and in fact most residential and commercial air conditioning units installed before 2006 use R-22. It will take some time for those units to be replaced with R-410A compatible units. According to the Montreal Protocol, refrigerant maintenance for commercial and residential R-22 air conditioning units will be allowed until January 1st, 2015. After that date, the unit will be allowed to be used and maintained but refrigerant recharges will not be allowed. However, if the air conditioning unit was installed properly than no refrigeration leak should develop, allowing for many decades of enjoyable use.
How long can a ductless air conditioner last?
The people behind ductless.ca have been installing ductless units in the Toronto area since the mid 1980's and only a few of those units have been replaced due to defective components. Most are still running just as well as the day they were installed. If the unit is properly maintained than you can expect more than 20 years of life.
What maintenance and service do ductless air conditioners require?
It is very important to keep the indoor unit filters clean. These filters are located in front of the evaporating coil behind the front cover. Some ductless units include smaller black charcoal filters which are required to be dusted off and then exposed to sunlight for at least 8 hours every 6 months in order to properly function. The charcoal filters usually last for 2 seasons (24 months). Also, some ductless air conditioner include Catechin filters which are also required to be cleaned regularly and replaced every two seasons.
The outdoor units need to be cleaned regularly, especially the coil which can trap leaves, dust, etc. All that is required is a soft brush (as to not damage the coil) and sweep the coil until it is relatively free of any obstructions.
Why is my indoor ductless unit not blowing the same amount of air as before?
Reduced air flow will also be caused by dirty filters, if the filters are clean than make sure the indoor unit fan is clear of any obstructions and that the leading edges of the blades are not covered with dust, mold etc. Determining if the blades are dirty is relatively straight forward, just straighten out the air-flow vanes and using a flashlight look through the vanes and the fan should be visible. The blades can be cleaned using compressed air. For more stubborn dirt, the fan might have to be removed from the indoor unit and cleaned more rigorously. ductless.ca provides full indoor and outdoor cleaning packages at competitive prices.
Is there any other maintenance or service that might have to be performed?
As with other household appliance, the indoor and outdoor units should be cleaned and inspected regularly. One other notable issue which might arise is with the line-set insulation. During the summer, animals such as raccoons and squirrels sense the moisture underneath the insulation and might bite at the insulation to access the water. This is obviously easier for the animals if the line-sets are placed horizontally such as on a flat roof as opposed to vertically against a wall. The missing insulation should be replaced as soon as possible in order to reduce line-set corrosion, and maintain air conditioner performance. ductless.ca provides line-set insulation replacement service.
If my remote control is not working or I cannot find it, can I still use my air conditioner?
Yes, most units have an emergency button on the indoor unit. Once this button is pressed the unit will go into emergency mode, maintaining 24°C (depending on manufacturer) until the button is pressed again, or the remote control is found/replaced and activated.