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5 Common HVAC Installation Mistakes and How They Cost You

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Last Updated on July 29, 2015


If you’re in the market for new HVAC equipment, you’re probably doing a lot of research into the type of equipment that’s best for your needs, as well as the brands that are highly rated. Did you know that it’s just as important to do your due diligence in choosing the right installer? Use this HVAC troubleshooting guide to help you understand possible issues.

Why installation matters.

Here’s why you want to be sure your new furnace or air conditioner is installed by qualified and experienced professionals:

  1. It reduces service costs and extends equipment life. When your new unit is installed by HVAC experts who understand both the equipment and your needs, it will be adjusted and tuned according to the manufacturer’s specifications and the requirements of your space. As a result, the equipment runs more reliably with less wear and tear on the parts. You’ll experience fewer breakdowns, and you may as much as double the life span of your equipment.
  2. It improves comfort and safety. HVAC installation is not one-size-fits-all. The design and size of your duct work and ventilation, the settings on your unit, the drainage and more all need to be correct in order for your unit to function effectively and efficiently. If mistakes are made by inexperienced or unethical installers, you could end up with temperature variance issues, humidity problems, and even carbon monoxide leaks.
  3. It reduces noise. If your ventilation is improperly designed or connected to the HVAC unit, the resulting noise can drive everyone in the building crazy. Choose a knowledgeable installer to avoid this problem.

Avoid common HVAC installation mistakes.

These common HVAC installation mistakes can seriously cost you. But they’re easy to avoid if you know what to look for.

1. Choosing the wrong size furnace.

If you are relying on your installer to recommend the size and capacity of your new furnace or air conditioner, make sure they are performing the necessary calculations to get it right. Don’t fall victim to the “bigger is better” mistake! An oversized unit can cause you all kinds of problems, find out why.

Even if the contractor isn’t just recommending the biggest unit you can afford, he may be automatically recommending the same size unit that you currently have. This can also be a mistake, because your old unit may have been incorrectly sized. This is likely if you’ve done any renovations without updating the HVAC system. Also, newer units are more efficient, and a smaller unit may now be able to adequately heat or cool your space.

2. Poor air distribution design.

Your furnace or air conditioner only does half the job. In order for that heated or cooled air to get where it’s needed, your duct system needs to designed correctly for the space and for the equipment. For example, the duct size needs to match the output capacity of the unit. Some contactors take shortcuts by using the old duct system when installing new equipment. But in most cases, the duct work should be changed to make sure it’s not leaking, and it works well with the heating or cooling unit.

3. Faulty duct installation technique.

Even when contractors do go to the trouble of installing new duct work, some use cheap materials and poor workmanship to do the job. Ducts may be assembled incorrectly, leaving cracks and gaps. Or, sometimes tape is used as a sealer instead of more permanent sealers. If this happens to you, you’ll have leaky ducts in no time. This increases your energy bills because heated and cooled air is wasted. It can also cause annoying noises, excess dust, drafts, and even humidity problems.

4. Poorly designed drain systems.

Air conditioners and today’s high efficiency furnaces can create a significant amount of waste water, which needs to be drained safely away from the system. If done wrong, you can end up with severe damage to your building from water leaks. In the cold weather, water backing up in pipes can freeze and cause your HVAC system to fail. Accumulating water can also lead to mold and air quality problems.

5. Incorrect exhaust.

Your furnace produces toxic gases, including carbon monoxide, that need to be vented to the outside of the building. If the exhaust flue or damper is the wrong size for your new equipment, fumes can back up and accumulate in the air. The next thing you know, your carbon monoxide detectors are going off and you’ll have a real mess on your hands (you do have carbon monoxide detectors, right?).

Don’t make a mistake by choosing the wrong installer!

If you simply go with the lowest bidder, this could easily be your fate. Thoroughly check the credentials of any HVAC installer or service provider before hiring. Look for the following:

  • Are they MSCA or NATE certified?
  • How experienced are their technicians?
  • Do technicians receive ongoing training?
  • Can they provide references for a job similar to yours?

After reading all of this, you may be concerned that your current HVAC contractor may not be up to snuff, but worried about switching. Learn more about how to be sure you’re making the right choice that with our free guide, Contract Confidence: Transitioning to a New HVAC Service Provider.
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