Say What?? Understanding How Your Equipment Works

SAY WHAT-part two-blog post

Here is the second installment of Say What??. If you haven’t read the first installment you can get caught up here.

Most homeowners know the importance of having a well running furnace and air conditioner however, many can become overwhelmed when a technician starts throwing out complex, industry specific, terms and acronyms. The following are few you may hear and will hopefully give you confidence the next time you’re talking to your favorite HVAC technician.


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MERV is short for Minimum Efficiency Reporting Value. You’ll most likely hear this acronym when talking about your furnace’s air filter. Summed up simply, there is a number assigned to every air filter. The higher the number, the better the filter is at filtering out airborne irritants and pollutants. So a MERV 11 filter is going to filter better than a MERV 7 filter.

However, bigger isn’t always better. Each furnace has a specific amount of airflow that’s needed to run properly. You need to make sure that the filter you use falls within the MERV range recommended by the furnace manufacturer.


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ERV is the acronym for Electronic Recovery Ventilator. Sometimes referred to as whole house ventilation, an ERV can help get fresh air from outside into your home. It also can dehumidify and pre-cool the outdoor air before it comes into your home during warmer months and will pre-heat and humidify the outdoor air in colder months.


While your furnace is listed to have a certain number of BTUs, which explains how much energy it needs to heat your home, that’s not what you’ll see on your utilities bill. You’ll probably see how many THERMS you used over the previous month. The utility company isn’t concerned too much about how much energy is generated from the gas your furnace use but rather the volume.


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A damper is used to restrict air flow to specific areas of your home. Some can be manually opened and closed, but most commonly dampers are used when a house is zoned. They automatically open and close based on what the temperature settings are on the thermostat.


This motor’s job is to pull gas and air out of the furnace and vent it out of the system and your home. You may have two PVC pipes sticking out of your home which supply and exhaust air for your furnace. The inducer motor turns on when your thermostat calls for heat and cycles to remove any combustibles that may be present in the furnace from the last time it was running. It continues to run until the temperature the thermostat is calling for has been met.

Photo from www.dtesupply.comIf you’ve ever seen the inside of your furnace while it’s running you may have wondered how the flames can run horizontally when fire usually is burning up. The draft that this motor creates is what causes those flames to burn horizontally.

Well that’s all for Part 2 of Say What??. If you have any further questions regarding your heating and air conditioning equipment please don’t hesitate to call or email us.

Phone: (262) 728-1655


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