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Should the Furnace Run Constantly?

green to blue gradient background with man looking and the furnace with a questioning look on his face

Ask the Expert: Should the furnace run constantly?

It’s cold outside! With a wind chill range of -40 to -65 degrees, many Twin Cities residents are staying at home. These freezing temperatures are being caused by a bubble of cold Arctic air pushing down south, says Climate Central. These temperatures are actually colder than some of the daily temperatures on Mars! —you know, the planet is 78 million miles further from the Sun on average (Smithsonian Magazine).

Given these temperatures and the fact parents are staying home watching their kids, many of them are noticing that their furnace is running constantly and wondering if that is normal. Others are tweeting about their furnaces not keeping up with the cold. So, what’s the issue here?

Size matters

Technician checking a machineOne of the 5 typical misconceptions is to think ‘the bigger the furnace the better.’ A system actually operates best when each component is properly sized and tailored for your home. Oversized equipment may cycle on and off more frequently, which can make the homeless comfortable and dramatically shorten the equipment's life span. If your furnace wasn’t sized properly, it may not be able to keep up with the demand for heat. To learn about the other misconceptions when buying new HVAC equipment, click here.

Single versus Variable Speed

House with circling arrows aroundIf your heating and cooling equipment is more than 12 years old, it probably came with a one-speed blower motor that cycles between ‘on’ and ‘off.’ These units have conventional split-capacitor electric motors that do not make speed adjustments. If your furnace is not running constantly, it’s more likely that you notice how cold some areas of your home get compared to others. That’s because the fan is not working all the time. On the other hand, the ECM technology in a variable-speed unit allows the blower to run at slower, more energy-efficient speeds, saving as much as 40 percent on electricity costs. At this time of the year, both are likely working at full power, but those with older equipment may be experiencing some discomfort. If you want to learn more, check out our blog post on electronically commutated (ECM) motors.

Furnace Efficiency

Upward column chartWith the cost of natural gas rising, heating bills are a source of worry for some. If you are one of those, you are not alone. One measure of the efficiency of a furnace is the Annual Fuel Utilization Efficiency (AFUE). An AFUE rating of 70 percent means that all but 30 percent of the fuel energy consumed, was converted to heat for the home. In other words, if you spend $100 heating your home, it means that $30 went up the chimney! Literally, you’re “burning money.” Currently, the U.S. Department of Energy has a set minimum AFUE standard for furnaces. In 2014, the minimum AFUE was 78 percent for a gas-forced air furnace. High-efficiency furnaces start at 90 percent AFUE.

Even if your furnace is highly efficient, the efficiency of the system is in big determined by the installation or retrofit. ENERGY STAR states that more than half of new furnace systems in U.S. homes do not perform to their rated efficiency as a result of improper installation. In fact, improper installation can reduce performance by as much as 30%. As an ENERGY STAR partner, we recommend that the work is performed by professionals. To learn more about equipment efficiency, visit our blog post on AFUE.

If you are unsure if your furnace is sized properly, or wondering about the benefits of a variable-speed furnace or higher efficiency, give us a call today.


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