HVAC Questions and Answers | TMS, Inc - Trumbull Mechanical Services
Q. I’ve lived in this house since it was built new 18 years ago. The last HVAC tech, who came in, said the system would soon need replacement. So I’ve looked into the matter. From what I can tell, it’s significantly more expensive to buy a system that is a lot more energy-efficient in heating and cooling than the standard systems. Why on earth should I consider spending substantially more for the high-efficiency units?
A: The difference in energy savings between a 10 SEER air conditioner—the lowest efficiency available—and a 13 SEER is 30 percent. Typically, the installer or the local serving utility can calculate your annual energy savings and you can then make a purchase decision based on, if desired, the simple savings you will realize for as long as you plan to be in the home.
You may also want to consider the environmental benefits inherent in energy efficient equipment or the fact that some manufacturers of higher efficiency equipment provide other incentives, such as a more comprehensive warranty, quieter operation, better humidity control, and other features, or that some utilities provide rebates for the installation of certain higher efficiency equipment.
Don’t too quickly overlook all the benefits of energy efficiency by focusing only on the system's first cost—think long term or life cycle, as they say in the building trade.
Q. The air in my house smells each year, at the same time of year – when I turn it on for the first heating of winter. That smell makes my family nervous. What is it?
A: Your furnace has been "unemployed" from early April or mid-May until late September, or even early November. You probably have not gone into the furnace on a weekly basis . . . with a feather duster.
Result: Dust accumulates on the furnace’s heat exchanger or your heat pump's resistance coils. Your nose is detecting the once-a-year odor of dust meeting high temperature. Typically, that smell disappears after two or three uses at the start of winter!
Q: How does my heating, air conditioning and ventilation (HVAC) system move air throughout my building?
A: Fans draw air in through grilles called returns, force air through ducts and into the conditioned space through supply registers.
Q. What are these ducts?
A: Most ducts are constructed of metal and installed by tradesmen called sheet metal workers. However, rigid fiberglass and flexible round ducts are also used, as well as "hollow" constructed spaces within the building – the space between floor joists is sometimes used as the return air path, for example.
Q. How can I get the right duct for my house?
A: Code-making bodies recognize construction standards developed by SMACNA, the leading authority on duct construction and installation. SMACNA contractors should be considered your preferred source of HVAC Expertise regarding duct selection.
Q. Should I just go with whatever the builder recommends?
A: The builder will not pay your future utility bills; you should take an active role in all energy-related design decisions. Regarding ducts, each material has characteristics that may favor its use in specialized applications. Sheet metal has a number of advantages – that’s why it has historically been the number one HVAC system choice and remains there today!
In fact, sheet metal use in HVAC is larger than all other materials – combined.
Q. What about the environment?
A: Those taking all elements of the construction industry toward "green" buildings are quite pleased with sheet metal. We’re talking here about basic metals – steel and aluminum.
These materials feature high recycling rates. Your new sheet metal duct installation comes, without your specific request, with a relatively high recycled content.
When your HVAC system is upgraded, the duct system may need to be removed and replaced with a newer design. It’s a good bet that the sheet metal duct removed from your house will end up back where much of it is returned to the industry – at a metals' recycler!
Also, sheet metal ducts can be easily and more thoroughly cleaned than other duct material choices if the need should ever arise.
Q. Should I just ignore the ducts?
A: Ducts that are improperly constructed, sealed, or installed can leak excessive amounts of air, provide poor air distribution, and can also "pipe" noise around the home.
Additionally, ducts can become dirty if put into service before the home’s construction is complete; there’s a lot of dust and dirt around most construction sites.
What’s more, ducts in older homes can become dirty after years in service, especially if filters are not changed on a regular service basis.
Ducts play a key role in energy usage from both how much friction the fan "sees" as it moves air throughout the duct system to how well they distribute heating and cooling to keep occupants comfortable.
Q. OK – How do I reduce duct leakage?
A: If you are building a new structure, make sure the HVAC system designer is specifying SMACNA’s prescriptive duct sealing standards.
Our companies and workers, who have trained in this industry and gained a vast amount of HVAC expertise, recommend prescriptive sealing of ductwork as one measure that will normally lead to the most cost-effective control of leakage without the need of expensive leakage testing.
Code-making bodies nationwide recognize construction standards developed by SMACNA, the leading authority on duct construction and installation.
Q. Doesn’t everybody recommend the best design and construction choices? Why can’t I just go to the phone book to find a contractor?
A: This Web site is designed to help homeowners find standards-conscious contractors that use well-trained and experienced workers. Click on the Find an HVAC Expert/Contractor link on the left to find contractors with trained, skilled, and knowledgeable workers – Your source of HVAC Expertise.
You’ll gain peace-of-mind by using our roster, rather than simply picking a name from the yellow pages.
A lot can go wrong in installing new HVAC systems, maintaining them, and servicing and repairing them. If you’re looking to solve a problem with the system, why introduce more risk into the equation?
Q. How often should we replace the HVAC system filter?
A: There’s no one-size-fits-all answer. The frequency of filter changes is driven by how much your HVAC system operates, which is driven by the severity of the seasons.
In some locations the cooling system might be in use more than four months of the year – to keep heat and humidity under control. If your house is in such a hot and humid location, you should pay a lot more attention to your filter than in an area where the air conditioning is seldom used. The same logic applies to heating. If the heat is used only on especially cold days during the three or so months of winter, then filters would be checked less often.
Start by checking the HVAC system’s filters at least once a month. Hold the used filter up to the light and compare it to a clean "spare." When light is obscured by captured dust and dirt particles, the old filter should be changed. Keep a record for one year and then replace the filter on that basis. At a minimum, it is always a good idea to change filters at the start of the heating and cooling seasons and then in between according to observed need.
Q. We’re a bit put off by the problems we have heard HVAC systems have had with mold. We have two children who are relatively far apart in age, and both of their schools have been closed in the past 18 months for mold clean-outs. I’ve also heard that some of these major mold clean-ups in schools don’t work! Can the same thing happen in my house?
A: Mold is a "whole building" issue with moisture and the broad answer to your question is to keep moisture out of the building and control and contain moisture that is necessarily in the building.
Roofs can leak. Window flashings can leak. Pipes carrying water can leak. Anywhere you have water or excess moisture, you must control and contain it. An HVAC system’s ducts can become contaminated – but the root cause is invariably uncontrolled moisture, not the ducts. Of course, if moisture enters a building – such as your children’s schools – in excessive amounts – and mold does grow – the ductwork can convey mold and excess moisture to other parts of the building.
But the solution isn’t replacing the ductwork or turning off the ventilation system. The answer is identifying how the moisture is getting into your building or out of control from in-the-building sources and correcting the problem. This is a “moisture management” issue.
Q. Does your HVAC Expertise contractor roster include Mold Specialists?
A: The HVAC Expertise team has bypassed what some have viewed as a golden opportunity to make a bundle of money from a panicked public.
Your question’s answer is: NO!
With hundreds of thousands of people with HVAC Expertise across the U.S. working at approximately 2,000 companies, we elected to avoid what perhaps you’ve seen in other industry segments.
Our contractors can help you diagnose problems with excessive moisture. They can help "fix" them, by investigating your building’s problems. Again, the bottom line for all of us is: The secret is to keep moisture out of the building and control and contain what is necessarily in the building. If you do this well, you will condemn any mold in your building to an early death!
Without moisture, mold cannot thrive.