The Advantages of Variable Speed Air Conditioning

New, Smarter Technologies Lower Monthly Utility Bills
While single- and two-stage HVAC equipment can be effective, variable-speed technology truly presents consumers with more energy-saving potential and significantly improved home comfort.

The term "variable-speed technology" simply refers to the ability of a air conditioner or furnace to automatically vary its operating speed. Though variable-speed units tend to cost more at the outset than single- or two-stage equipment, they can operate far more efficiently because their outputs vary according to the conditions of the home, rather than running at full or a single reduced capacity for the duration of a cycle. This can result in significant savings on monthly utility bills, reducing the payback period and offsetting the initial investment from the homeowner.

A variable-speed air conditioner or furnace is able to operate in increments of its full capacity. Current variable-speed condensing units on the market provide operating ranges from 100 percent capacity down to about 25 percent. The home rarely needs its HVAC equipment to run at 100 percent capacity; this is perhaps only required for situations such as the first time air conditioning is needed in the summer or heat is needed in the winter, or the highest seasonal extremes in temperature. However, those cases are rare. In fact, weather data shows that, on average, most locations in the United States see the need for 100 percent capacity less than 5 percent of the year, and see the need for part-load capacity (approximately 75 percent of full load) for 60 to 80 percent of the year.

That's where a variable-speed unit earns its keep. A variable-speed unit can determine when a home does not require full capacity and can adjust to provide incremental operation. For instance, consider a home where the thermostat is set to maintain a steady 70 degrees in the summer, but one bedroom has west-facing windows and gets warmer in the afternoon. When installed with a zoning system, a variable-speed system can recognize that the majority of the house is perfectly cool, with the exception of that one room (or zone). The unit will then change its operation to run at a lower percentage of capacity and cool only that particular zone, thus saving energy by running at a lower speed while keeping that bedroom as cool as the rest of the house.

This situation is also an ideal example of how zoning can complement a variable-speed unit perfectly. The unit can communicate with the control and the rest of the system to determine which zones need more or less capacity, and then act accordingly.

Think of a variable-speed system like the climate control in a new car. When the system is set to a given temperature, its output capacity ebbs and flows to maintain that constant setting. Sometimes it works harder, and sometimes it works at a lower capacity to keep the temperature at the desired setting. A variable-speed air conditioner is similar in principle to this concept. Conversely, compare a furnace or air conditioner to an oven. You wouldn't buy an oven that only has off and high settings, would you? So why would you buy a single-stage HVAC unit? Like an oven with single-degree variances, a variable-speed air conditioner or furnace allows the user to tailor home comfort performance to the specific needs of the occupants.

Another advantage to variable-speed equipment is that it can more effectively control humidity levels in the home. A variable-speed air conditioner is running optimally when it cools a home at a lower capacity during a longer cycle. This low and steady approach allows the air conditioner to remove more moisture from the air, since the cycle is longer and more consistent. Plus, a home with less humidity feels cooler than a more humid home, which can also allow the homeowner to keep the thermostat at a higher setting during the warm summer months. In contrast to this efficient operation, a single-stage system will simply cycle on and off based on the temperature demand, not the humidity level. This frequently leads to an imbalanced space that is either too cold but with satisfactory humidity levels, or the right temperature with humidity levels that are too high.

In the case of a variable-speed furnace, its fan motor can work with an outdoor air conditioner and thermostat with a humidity sensor to provide the same effects to the indoor air. It will allow the conditioned air to be added to the home at a lower, consistent speed, pulling more moisture out of the indoor air. If the control senses that the space needs dehumidification but the temperature is at or near the setting, the system reacts by reducing compressor speed and decreasing airflow for maximum dehumidification. This allows the system to operate longer without drastically over-cooling the space. This also means that a homeowner could increase the cooling set point and still be comfortable because the humidity is under control.

Intuitively, one would think that if a system was smart enough to not need to operate at maximum capacity, then it would run more efficiently. That is exactly the case with variable-speed units. By running at lower speeds and consuming less power while doing so, this type of system can save homeowners considerably on their monthly utility bills.
Overall, variable-speed technology allows the home comfort system to run more efficiently by running smarter. With technology available today, homeowners do not need to contend with full-blast, short cycles in order to heat or cool their homes. With variable-speed equipment, they can enjoy more consistent temperature maintenance, better humidity control and, ultimately, lower monthly utility bills.
*Excerpted from HVACR Business originally published: 01.01.14 by John Gibbons

Need a new system?  Surgi's can help.  Need a healthier, more comfortable life?  We can change the way you feel about your home. 


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The Final Phase-Out Of R-22


In 2010, regulations required that the manufacture of air conditioning systems using R22 freon cease.  Many manufacturers found a loophole and continued to produce these units through 2015 by shipping the units without refrigerant.  These "dry ship" units are still being installed today as inventories are depleted.

Surgi's has not installed a system using R22 since 2006.  We felt that the scarcity of R22 would place an undue burden on our customers in the future.  We also support the reduction of greenhouse gasses.


Meanwhile, the production of R22 has been dramatically reduced from a high in 2013 of 63 million pounds to 18 million pounds in 2016.  As a result, the cost of R22 has increased 500% in the last 5 years.  The cost of charging a 3 ton air conditioning system with R22 now costs between $600 and $1,000.

If Your R22 System Fails You Have Options  

Some air conditioning companies are aggressively trying to sell new air conditioning by condemning older systems that may only require relatively minor repairs.  Surgi's offers free second opinions for customers that have paid a company for an evaluation and may have second thoughts about their diagnosis.  Just provide a copy of a paid invoice to another company less than 30 days old and we will confirm the diagnosis of your system at no charge.

Surgi's has had some success with modifying an existing evaporator coil with a valve to make it compatible with the new condensers and refrigerant (R410a).  This solution is considered temporary in that if the old coil is not rated to handle the operating pressures of R410a it may develop leaks.  Also, the cooling capacity of this configuration may be reduced.

If you have gas heating and your heater is in good shape you have the option of only replacing the condenser and evaporator coil.  When your furnace requires replacement, you will pay a premium for a new installation versus having the heater replaced as part of a complete system installation.

If you do require a new system we have teamed with several manufacturers to provide 0% financing for up to 60 months on many of the new, high efficiency systems in the marketplace.  The efficiency savings provided by these new systems can often approach the monthly financing payment.

Feel free to call us at 469-4232.  We're here to help

Need a new system?  Surgi's can help.  Need a healthier, more comfortable life?  We can change the way you feel about your home. 


Questions?  Call 469-4232.

While you are researching try the following articles on Surgi's website:

Read Unbiased Consumer Reviews Online at AngiesList.com