Dangers of Blocked Cold Air Registers A drop in HVAC equipment efficiency, which results in an increase in energy consumption and operating costs. Additional strain and wear on the HVAC components, making them more vulnerable to breakdowns or a premature failure.
While it can be tempting to block the cold air returns for rooms you're not using to save energy or place furniture against them to arrange a room, blocking these registers is one of the most common ways to undermine your cooling and heating system.
Return air ducts must be sealed and unobstructed — Sealing return air ducts is just as important as sealing supply ducts. Sealing all duct section connections with mastic, a specialized rubbery sealant, or with metal tape prevents air leaks.
Return vents are usually larger than supply vents and are in large rooms in the home. The return vents in your home help equalize the pressure that changes as your HVAC system heats or cools your home. These vents should never be fully closed because closing them off restricts airflow and strains the system.
A build up of pressure can be caused by covered vents. This could lead to a cracked heat exchanger which in turn can lead to leaking carbon monoxide. Covering your vents can damage your HVAC system and cause cracks that could allow air to escape your ducts. This can lead to higher energy bills.
On the heating side, if you block off the return, the exchanger can overheat. “In extreme examples, it can crack and fail,” Smith says. “They're all designed to have that proper airflow and bad things can happen when that's thrown out of whack.”
You most likely thought covering your air vents would certainly save you energy, but it does the opposite. Considering that this could damage your cooling and heating system, fractures and other damage could allow air to leave your air ducts and cost you much more in energy bills.
Hot air rises and cool air sinks. Therefore, opening the right return vents in the summer and winter significantly improves the distribution of air by your forced-air system. You'll also enjoy more even heating and cooling throughout your home. In the summer, open your high returns and close the low ones.
Even one blocked vent in the home can cause an inefficiency in air flow, which means your HVAC system will likely have to work harder to achieve the desired temperature. The result may be a home that is riddled with uneven temperatures from room to room.
You should never block your air return vents. Period. However, if you're looking to keep your home cooler in the summer, you can try closing lower supply vents and keeping upper ones open, allowing cooler air temperatures to come in from above and sink throughout your house.
If you prioritize heating, put the HVAC and vents in (or below) the floor. This principle works for return heating vents as well. Place returns for cooling in the ceiling where the warm air congregates and heating returns in or near the floor where the cold air congregates.
Blocked or insufficient return air can lead to reduced airflow from your vents. Symptoms include weak airflow and uneven cooling or heating throughout your home, with some rooms feeling much cooler or warmer than others. Homeowners should regularly check vents for consistent airflow.
Give It Some Space
Home Inspection Insider explains that an air return vent needs 6-12 inches of space in front of it, and recommends that you do not put large, bulky furniture like couches and bookshelves in front of an air return vent.
Make sure you air seal the ductwork to maximize the efficiency of your HVAC system. Did you know you only enjoy about 75% of the air your system heats and cools?
Does Every Room Need Air Return Grilles? While it is a myth that air return grilles are required in each and every room in the house, it is definitely necessary to have more than one of these grilles installed at strategic places in the house. The most important place to have these would be the bedroom.
Dangers of Blocked Cold Air Registers
If your HVAC system is designed this way, blocking off a single return vent can wreak havoc on the system and lead to: Pressure imbalances that let allergens and pollutants get pulled into your air supply from unconditioned areas.
Closing vents in individual rooms will not help your energy cost, but actually hurt your system. “Closing vents puts a strain on the system, which in turn causes the system to work harder,” Martin says.
Here's why it is a problem: If that air isn't passing through the vent, it is being backed up in the ductwork, which causes pressure to build up within the system. This pressure can cause your system to overheat and break down.
Dirty filters, leaky ducts, and poor insulation can cause cold return vents. Leaky ducts often cause cold air to blow even after cranking the heat up. 20-30% of air, especially hot air, is lost because of leaky ducts. Cracked, holey ductwork needs sealing or replacement.
When it comes to cooling your home, return vents are best installed near the ceiling so they can draw in any hot air that has risen. Supply vents should also be placed high on the wall for better distribution of cold air throughout the room.
Piping shall not be installed in or through a ducted supply, return or exhaust, or a clothes chute, chimney or gas vent, dumbwaiter or elevator shaft.
Blocked vents increase air pressure in your ductwork, which can create cracks and leaks. Clear vents ensure every room in your home gets good circulation so your system can work as designed. Have a piece of furniture sitting over a vent? Try using an inexpensive vent extender to direct air out into the room.
Return air vents connect to your return ducts, and they're typically larger than supply vents. Again, depending on the design of your ductwork and home, HVAC return vent locations vary but are often in central areas, kitchens, bathrooms, and pollutant-prone areas so as to best collect stale or dirty air.
When a homeowner blocks off their baseboard heater with a piece of furniture or a blanket, it's very easy for the heater's airflow to become restricted. As a result, flammable items nearby are more likely to ignite and the heater itself becomes less effective at heating the home.