This is a good question. On the face of it, this seems to be a reasonable action because you will save money on your heating bill. Unfortunately, this is incorrect, and in reality, the exact opposite is true, and it may even lead to other more serious problems. In this article, we will examine some of the consequences of closing vents in your unused rooms.
Will Closing Vents Save Energy?
The short answer is no, but to expand on that simple rebuttal, we need to consider the balance that exists within your HVAC system. Most people are not aware that a great deal of thought and planning should go into an HVAC system installation. The heating and cooling equipment must be carefully matched to the home with a complex load calculation. You can find simple load calculation tools online, but they are only based on the square footage of your home. These online tools don’t take into account many other factors, such as insulation levels, home orientation, room layout, and more.
Any good HVAC system installation will ensure that the ductwork is able to handle the volume of air generated by the system. The blower unit will force the treated air (hot or cold) through the ductwork and out of the vents to each room in the home. The blower will suck indoor air into the system via your return ducts, and this is then directed back into the home via the supply ducts. So, when you close a vent in an unused room, you’re not helping your system by making it work less. The opposite is true; you are making the HVAC system work harder as it attempts to transport the treated air. When your heating and cooling equipment is working harder, it will consume more energy, and this will be reflected in your utility bills.
Can Overworked Equipment Fail?
Yes, if you think about any complex piece of equipment, it’s always more liable to break and fail when it’s working hard. The individual components are placed under strain, and this will affect how they interact with other parts in the system. When your HVAC system is working extra hard, it will be more likely to fail when you need it most, and it may even have a lower than expected lifespan. An HVAC system represents a significant investment in your home comfort, and it makes sense to protect it.
2 Reasons to Avoid Closing Your HVAC Vents
To illustrate this point further, let’s take a look at two good reasons why you should avoid closing your HVAC vents in unused rooms:
- Split Capacitor Issues
The split capacitor or PSC blower is the aforementioned unit that creates the airflow around your home and through the HVAC system. When the system becomes overworked, this component will slow down permanently, and it will need to be replaced. This happens because the blower unit cannot handle the increase in the air pressure in the system. Ultimately, this will degrade the oxygen levels, which may affect the indoor air quality (IAQ), but there is a greater problem.
When the air conditioner evaporator doesn’t receive sufficient oxygen, it will start to overcool, and it will be coated with ice. This ice forces the liquid refrigerant to flow in the wrong direction, which is back into the compressor unit outside. Sooner or later, this will destroy the compressor leading to another expensive repair bill.
This can also cause problems in winter. The heat exchanger can crack if overheating occurs due to a lack of airflow. This may cause carbon monoxide poisoning, and it’s a common cause of many house fires every year. A blower unit is one of the most expensive components in your system, but replacing it may be the least of your problems.
- Electronically Commutated Motor Issues
The second blower problem is when the Electronically Commutated Motor or ECM blower is required to work too hard. This will occur when the air pressure in the system has increased, and the ECM blower attempts to compensate for the change. The ECM blower is designed to adjust its speed automatically when certain conditions are met. This includes the change in air pressure that occurs throughout the system when the vents in one or more rooms are closed. The ECM blower will become overworked, which can really drive up your energy bills.
What is the Solution?
The easiest way to deal with this problem is to keep the vents open in every room in your home. Sometimes, when a room is not in use for a while, the vent can even become covered. The most common things that are found over vent openings include drapes, tall furniture, stored items, old boxes, and more. If the vent is closed, make sure to open it up and consider cleaning it to remove any dust that may have accumulated there. If you want to boost the airflow, make sure you change the air filter in accordance with the guidelines detailed in your owner’s manual. If you’ve misplaced your owner’s manual, you can usually find a free pdf copy online for your HVAC system.
What if I Don’t Want to Leave My Vents Open?
It’s understandable to want to keep your vents closed for a number of good reasons. But, hopefully, we’ve made a good case against that practice, and you’ve been convinced to alter your habits. Remember that a closed vent in an unused room will not lower your energy bills; it will raise them and damage your HVAC system at the same time. If you absolutely have to have closed vents, there is an option that may suit your needs. You can install smart vents that have sensors that detect when someone enters and leaves a room. These vents can even open automatically to equalize the air pressure and protect your HVAC system components.
If you want to learn more about installing smart vents for your home or your system needs some essential maintenance, contact your local HVAC specialist today.