HVAC Myths

HVAC Myths explained …

As Mark twain said … It ain’t what you don’t know that gets you into trouble. It’s what you know for sure that just ain’t so (… that gets you into trouble). When it comes to HVAC Systems, who can blame you for being sure of facts that just aren’t true? This industry has been hit hard with a lot of complaints about inept contractors right up to outright fraudulent contractors. Myths and misconceptions have been created and even perpetuated by these very same contractors. As a result there is information that’s not accurate, there are convenient half-truths, and then there is information that’s just plain wrong that has been accepted as fact. We have collected as complete a set of these “issues” as we could … feel free to contact us to ask any question about HVAC that might not be addressed here …

The unit is fine because it sounds fine.

Not necessarily so … internally the unit may not be functioning properly. A qualified technician will diagnose issues that aren’t obvious to the eye (or ears) and recommend the necessary repairs. But be sure of one thing … get the back-up information behind why the repair is necessary. If they are in a position to recommend a repair, it should be based on data not gut feel.

AC units need a new refrigerant charge every spring/summer.

A qualified technician will measure the level of refrigerant and only add when needed. It could be each year (indicating a different problem!) – or not for years on end. The need to replace refrigerant would be in the event of a leak in a sealed system … so there is need to consider the cause and repair of that problem.

Maintenance plans are not worth the money.

Have you ever noticed that A/C fails when its 95 degrees out (never 70) and heating systems fail when it around 5 degrees out. Our experience is that a properly maintained system is more than 98% less likely to fail if it is maintained by qualified technicians. A qualified technician will look to pro-actively inform you of potential problems before they occur.  Not only will this save you from needing emergency service (typically more expensive than planned repairs), it will allow you to budget for the repair. People that say maintenance plans are not worth it probably had one and never had an expensive repair. Apparently they didn’t understand it may well have been because they maintained their equipment that this was so!

Blocking off air vents will save money in the long term.

Really?  Blocking off vents will make the unit work harder, using up more energy and creating more wear and tear on the equipment. If you don’t need cooling or heating in a particular room, then this may be so as long as the thermostat controlling other rooms isn’t in that room! Don’t try to save a few bucks on the front end by skimping on adding a zone or two – it may cost you more in the long term.

The thermostat’s location is not that important.

Someone actually said this … If your thermostat is located in an area that (for instance) is in direct sunlight and you are trying to cool or heat, it will record a bogus temperature, and will not allow for consistent heating or cooling. (Gee – it works great on cloudy days!)

HVAC systems are inexpensive to operate.

Yeah … and the check is in the mail. A home’s energy bill can be as much as 50% HVAC usage depending the time of the year, the type of unit, and the square footage of the home. A properly sized energy efficient system (if installing new) or having a maintenance plan for an existing system will help save on energy usage – but anyone trying to sell you a system that is telling you they are inexpensive to operate – well, buyer beware!

Leaving a fan running in a room when it’s empty will allow the AC unit to cool the room faster.

File this under “if a tree falls in the woods does …” A fan moves air against a person to make them feel cooler. The air temperature isn’t lowered. What you are doing is wasting energy. Use fans and A/C units when people are in the room … which brings us to:

You should turn the AC off all day if you are not at home. 

When it is hot and humid, it is advisable to keep the AC running when you aren’t home to reduce humidity and allow the system to cool to a comfortable level in a reasonable time. If the outside temperature and humidity don’t warrant this, then there is no benefit of keeping the AC unit running continuously – but there is definitely reason to run the AC on hot and humid days when you aren’t home.

For faster cooling, set the temperature below what you want it to be.

Sounds logical, but AC systems cool at a set rate. You can’t make it cool faster by setting the temperature lower.

It’s best to purchase the biggest unit because they work best.

This one is just soooo wrong! HVAC units work more efficiently and effectively if they’re specifically suited for the square footage, insulation level, amount and facing direction of windows and more …  of a home and the needs of the homeowner. Be sure your contractor performs a Manual-J Load Calculation (that considers all of the variables) to properly size your AC system!

Temperatures variation from room to room can’t be corrected.

It ain’t necessarily so! It could be something small, such as replacing a thermostat, or taking measures to improve the air flow so the unit can cool rooms evenly. Not to sound like a broken record, but our experience is that the great majority of existing systems have over sized units with undersized duct work. Some less costly options might be sealing the ducts or adding returns. It isn’t necessarily cause to replace a well-functioning system.

My old unit isn’t big enough; it needs to be replaced.

See above … a properly trained technician can measure loss in your duct system and provide options to correct any issues. You might also be able to get better performance if the unit is in need of maintenance.

Price is the most important factor when making a purchase.

Not to sound harsh, but who wants to talk to a price shopper? The level of service, before and after the installation … the level to which the contractor lines up your available rebates and incentives, and the payment plans that are available can make a much greater impact on your bottom line than just “price”. The most important factor is who you choose for the installation. A properly designed system that has had all of the available rebates and incentives applied and then financed (as needed) by preferred sources will provide you not only the “best deal” when installed, but will perform reliably and cost effectively for the life of the system.

Filters don’t really need to be changed regularly.

True … as long as you don’t want your system to run efficiently. A dirty filter constricts air flow making your system work harder. If there is a common theme here, it is that regular maintenance will improve system performance and extend the life of your system.

You don’t need to have the system checked unless there’s something wrong with it.

Need I say again?  HVAC units need to be maintained regularly.  Annual, semi-annual, or even more frequent maintenance depending on the amount of use will keep it in top running condition.

Buying an efficient air conditioner or furnace will automatically reduce my utility bill.

That’s not the whole picture … maximum savings and comfort will not be realized if the equipment is not sized or installed properly. Of course we recommend buying energy efficient equipment … but that’s only half the battle.

Heat pumps do not have a long life expectancy because they operate 12 months of the year.

Not so … Dirt, improper application, poor service and lack of preventative maintenance tops the list for heat pump failures. As long as it is properly cared for, the life expectancy of newer heat pumps exceeds 15 years as long as they are properly maintained

I don’t need to be concerned with all this talk about “Indoor Air Quality”.    

If you’re 95 and have been smoking two packs of cigarettes a day since you were 15, this may be true, – you’re probably immune to just about anything that gets in your lungs …  but if you have any sensitivity to mold, mildew, fungus, dust mites, pollen, bacteria … or your pets or children do … well, you get the picture.

What is the bottom line here?

The bottom line is you really need to know and trust your HVAC Contractor. Our goal is to be that contractor … but we also say to check around and get to know the people you are doing business with.


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