Updated January 17, 2024

Are you looking for ways to make your home more comfortable and to save on your heating and cooling costs? If so, upgrading to a variable-speed HVAC system is a great option. Variable-speed HVAC systems have several major advantages and provide many important benefits compared to traditional HVAC systems. This guide will explain all you need to know about variable-speed HVAC systems, how they work and why they can be such a great choice for your Des Moines, IA, home.

Comparing Traditional and Variable-Speed HVAC Systems

Most residential HVAC systems have a single-stage or two-stage furnace paired with a central air conditioner. Some homes also have a single-stage or two-stage heat pump to make heating and cooling more efficient. A single-stage HVAC unit has a single speed or power setting, which means it always runs at 100% of its total heating or cooling capacity.

Two-stage units obviously have two speeds or power settings and will typically run at approximately 65% capacity. Two-stage units can run at full capacity when more heating or cooling is needed, such as on extremely hot or cold days or when the home is much hotter or colder than the desired temperature. However, they will typically run on the lower setting around 80% of the time.

Variable-speed HVAC units typically have several different settings and can usually operate at anywhere from around 25% to 100% capacity. This allows them to automatically regulate how much heating or cooling they produce at any given moment. This helps to make the system much more energy efficient while also ensuring that the temperature in the home remains consistent.

Variable-speed air conditioners and heat pumps work by regulating the compressor speed to speed up or slow down the rate at which the refrigerant moves through the system. Variable-speed furnaces are also referred to as modulating furnaces. These units have a modulating gas valve that can open and close to regulate how much gas the unit burns at one time. All variable-speed HVAC units are paired with a variable-speed blower or fan. This provides a huge range of settings and can speed up and slow down to regulate how much air flows through the system.

How Variable-Speed HVAC Systems Work

A variable-speed HVAC system works by monitoring how quickly the building is heating up or cooling down. These systems will typically start running at around half speed, or 50% of the total heating or cooling capacity. On much hotter or colder days, the system will then slowly start ramping up. It will run at increasingly higher speeds until the temperature in the home starts to near the desired thermostat setting.

One thing that sets variable-speed systems apart from other models is that they won’t just turn off when the thermostat senses the building is at the correct temperature. Instead, variable-speed systems are designed to run almost constantly at a much lower speed. In fact, they will usually only shut off during much milder weather when almost no heating or cooling is needed.

Once the thermostat senses the home is at the desired temperature, a variable-speed system will slow down. It will only produce however much heating or cooling is needed to keep the temperature constant. The system will then continually adjust the rate of heating or cooling as needed to prevent temperature fluctuations. This ensures that the home always stays at the desired temperature. A variable-speed system will also prevent issues with cold or hot spots. This happens when a single-stage system only runs for a few minutes at a time.

How a Variable-Speed HVAC System Can Save You Money

Installing a variable-speed furnace, AC or heat pump in your home can save you a large amount of money compared to a single-stage or two-stage unit. The fact that variable-speed systems run constantly leads some people to believe they use a lot of energy. In fact, the opposite is true.

When a variable-speed system runs at only 50% capacity, it will use around 75% less energy than a single-stage system that is running at full speed. This means that a variable-speed AC or furnace could easily save you several hundred dollars a year. This is compared to the cooling or heating process using a single-stage unit.

Variable-speed HVAC units are much more expensive than single-stage or two-stage units. However, a variable-speed unit will almost always be less expensive in the long run since it will save you so much money on your energy bills.

Variable-speed HVAC systems are much more energy efficient because they use much less energy when running at lower speeds. Also, single-stage units, especially central AC equipment and heat pumps, draw a large amount of electricity to start up the compressor and blower motors at full speed. Most units use around three to five times as much electricity when starting up compared to what they use when they are running. Single-stage units will usually cycle on and off two or three times each hour. This continuous cycling leads to lots of extra energy consumption.

Other Benefits of Installing a Variable-Speed HVAC System

Variable-speed HVAC systems provide other important benefits, such as improving the air quality in your home. Since the system will run constantly, the air in your home will get filtered and circulated much more frequently. This means that the HVAC system’s air filter will trap far more dust, pollen and other allergens, allowing you to breathe more easily.

A variable-speed AC or heat pump is also far superior to a single-stage unit in terms of humidity control. All air conditioners draw moisture out of the air to help control the indoor humidity level. As the unit runs, moisture condenses on the evaporator coil so that the humidity level in the air flowing through the system decreases. By running constantly, variable-speed units have been shown to be capable of removing around 400% more moisture than single-stage units. This can be a huge help in places like Des Moines, where the summers tend to be extremely humid. The air inside a home often feels very sticky and muggy.

By keeping the humidity level in your home much lower, a variable-speed HVAC system will also help to prevent issues with condensation and mold growth. This is also important for maintaining better indoor air quality and preventing allergy issues.

Another advantage of variable-speed HVAC systems is that they are extremely quiet whenever they’re running at lower speeds. The system will produce around the same volume of noise when running at full speed, but this typically happens less than 20% of the time.

With more than 20 years of experience, Golden Rule is an excellent choice if you need any HVAC installation or repair services in the Des Moines area. We offer a wide selection of traditional and variable-speed furnaces, AC units and heat pumps. We also specialize in HVAC repairs, maintenance and indoor air quality assessments. For more information on the benefits of upgrading to a variable-speed HVAC system or to schedule any heating, cooling, plumbing or electrical services, give us a call today.


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