Your home comfort will suffer and you will have issues with your indoor air quality. Furthermore, it is expensive to operate a furnace that is too large. Your monthly energy costs will increase. Also, a system that is too large will require more repairs than one that is properly sized.
Your home will be uncomfortable. When your furnace is too big, it will blast your home with too much conditioned air at one time. This can make your rooms feel too warm when your furnace is operating and lead to major temperature swings in your home.
Larger unit may be more efficient (larger condensers generally are), but make sure you don't oversize it. If the unit is oversized it'll cycle more frequently, which is hard on it. Oversized can also cause some issues with humidity if you have any outside air connections.
The more BTUs a furnace has, the larger the area it can heat. However, bigger isn't always better. If your furnace has insufficient BTUs, it'll work non-stop and never keep your home at a comfortable temperature. Alternatively, a furnace with too many BTUs will frequently cycle and be inefficient.
No, you should not put a bigger blower motor in your furnace.
An oversized furnace can cause a number of problems, including increased energy costs, shortened furnace life, and uneven heating. If you're not sure what size furnace you need, talk to a heating and cooling professional.
When increasing the blower speed, loosen the setscrew a little bit. This is the part that holds the pulley to the furnace's driveshaft. Turn the pulley one rotation clockwise on the shaft. If you want even more speed, do two rotations.
Again, because oversized HVAC units blast your home with cool air instead of cooling it down gradually, the temperature swings prompt your HVAC system to start up and shut down in rapid succession-a condition commonly known as “short cycling.” Short cycling can wreak havoc on your HVAC system if left unchecked.
An air conditioner with BTUs that exceed the recommended square footage in your home may also take on more wear and tear over time because it will initiate its on/off cycle more frequently. It could also create a subpar cooling experience because your AC's compressor may turn off much sooner than it should.
An undersized furnace will run constantly (running up your energy bills) without ever properly heating your home. It won't ever meet your heating needs. An oversized furnace will heat your home quickly and then shut off.
Each section of ducting that gets installed in your home needs to be appropriately sized for your HVAC unit to perform efficiently. If your ducting is oversized or undersized, it could lead to premature wear out of your heating and cooling units and an uncomfortable living environment.
Neither oversizing nor undersizing your AC unit is ideal. Both scenarios can lead to issues with efficiency, comfort, and longevity of the system.
A basic rule of thumb for furnace size calculation is that it takes 30 BTUs for every square foot of house. So, if you have a 1,000 square foot house, you need a furnace that has a 30,000 BTU output.
The standard settings for most furnace fan limit switches are 200°F to shut off the burner, 130°F to turn off the blower, and 100°F to turn the blower back on.
An oversized furnace causes excess wear and tear, higher energy bills, and more problems (and expenses!) that make it tough to stay warm in the winter. This article goes over how to tell if the furnace installed in your home is too big.
To heat a 40×60 shop, which is 2400 square feet, you'll typically need between 108,000 and 132,000 BTUs.
But when an oversized unit is in place, it cools far faster and limits the cycle, which causes muggy, damp conditions in many cases due to high humidity. This can also lead to mold formation and a musty, uncomfortable smell.
An oversized HVAC system cycles on and off more frequently than necessary. This short-cycling leads to increased wear and tear on components, reducing the overall lifespan of the system. It can also result in uneven heating or cooling, creating uncomfortable hot or cold spots in different areas of your home.
Well-maintained furnaces can last 20 years or more. Replacing the blower motor with one too big for the system will significantly reduce its lifespan. The oversized blower fan will strain other parts, ranging from the heat exchanger to the burners. As a result, they'll break down faster.
Running your furnace fan continuously in winter has its pros and cons. It can improve air circulation and quality but may also lead to higher energy bills and increased wear on your system.
If the speed is set to high or too low, the air volume will also be too high or too low for the system to function properly. Setting the fan speed too low will usually cause the evaporator coil to freeze. If the fan speed is too high, it can cause the AC condenser to short-cycle or turn on and off constantly.