If you remember your high school physics classes, you will already know that hot air always rises and cold air falls. This scientific principle may be more applicable to your own home if you have rooms that are hotter upstairs and colder downstairs. This may seem like an insurmountable challenge, but there are things that you can do to fix these problems if you understand the causes and take action.

Check the Air Filter

This is good advice for many problems related to your HVAC system. Checking, cleaning, and replacing air filters is simple and the full details are in your owner’s manual. A dirty filter can make your entire system less efficient, this wastes energy and it can even damage your system. If you check the air filter and it’s clean you could switch it for a low resistance alternative that won’t reduce the airflow to the upper floor. An air filter with pleats may restrict the airflow and a cheaper fiberglass unit may work better.

Second Floor Registers

If your HVAC system has not been inspected or cleaned in a while, it’s a good idea to get a tune-up by a local certified HVAC specialist. Another problem could be the second floor registers that may be blocked by drapes, furniture, stored items and more. The dampers may be closed because the room is not in use, but this will lower performance and efficiency. Improving the airflow in underused rooms will boost the HVAC efficiency throughout the entire and it will prevent the system from overworking. If you need to cool an unused home during the day, close the curtains on south and west facing windows. Another energy saving tip is to switch to LED bulbs that don’t generate any ambient heat.

Check the Thermostat

The key to good distribution of treated air in your home is the thermostat fan. Many people set the fan and leave it without understanding how it can affect their home heating and cooling. Setting the thermostat from the “Auto” to the “On” setting may seem inefficient because the fan is running constantly. But, this helps to distribute the air evenly throughout your home, making the system more efficient overall. It’s also important to have multi-stage or modulation AC systems sized correctly to match your home. If you’re unsure about the performance and energy efficiency of your system contact a local certified HVAC specialist and ask them to check your system.

Hot Attic Spaces and Roofs

If you have an attic with poor insulation levels, it will be hot in summer and cold in winter. This will draw treated air away from where you need it most and your energy bills will be higher. In summer, a badly insulated attic could reach 140ºF and more which rivals the hottest sauna! Your attic needs adequate ventilation to release this heat in summer and good insulation to keep any heat inside when the weather turns cold.

Leaking Ductwork

Most ductwork systems have a few leaks and an average home may have 25% leakage or even more. When the ductwork is porous it reduces the levels of indoor comfort and wastes money. After all, the treated air that you’ve spent valuable energy creating is escaping to other areas and it may be leaving your home altogether. This will cause your system to work harder than it needs to and overworked equipment is prone to failure. Another problem is gaps in the ducts where dust, debris, allergens, and other materials can enter the circulated air. This will lower the indoor air quality (IAQ) which may trigger allergic reactions or affect those with pre-existing breathing conditions. In terms of the disparity between the upper and lower floors, it’s not surprising that leaking air can create cold spots upstairs. Temporary repairs can be made with duct tape if you can find the leaks but you will need to contact your local HVAC specialist and get them to assess the system. In many cases, a repair may be possible but it’s often less expensive to simply replace the ductwork entirely.

Uninsulated Ductwork

This may not seem as drastic as leaky ductwork, but it can be a trickier problem to solve. When you have air running through the hot attic it can enter the top floor at several degrees warmer than the temperature downstairs. The heated air may even go back into the downstairs and many people attempt to compensate by adjusting the temperature. This may be solved with extra insulation but many sections of ductwork are hard to reach. If you have plenty of ductwork on the upper floors, you may be able to balance the dampers by closing them slightly. This will help to move air from any cooler rooms to other areas in the home that feel warmer. Investing in good insulation for your ductwork is a better idea and it may lower your energy bills too.

Installing a Zoning System

If you have sufficient ductwork, it may be possible for your local HVAC specialist to install a zoning system for your home. This is a pair of separate thermostats and a series of motorized dampers to move the area to specific floors or areas where treated air is required. This may seem complex, but it’s easy to use and you can set up the zones to tailor the temperatures to a very precise degree. Sadly, this solution won’t work for an older ductwork system and it may require a compatible furnace and multi-speed AC unit.

Running Separate Systems

If you’ve attempted one or more of the solutions presented here and had no success it may be time to consider a radical solution. The root of the problem may be that your system simply isn’t powerful enough to heat and cool the upper and the lower floors at the same time. In this case, you could consider installing a second unit and assign each unit to a separate floor to split the workload evenly. Adding a high-velocity system may be the solution or you may need a ductless split system that is designed for this type of application.

If you have problems with temperature variances in your home, contact a local HVAC specialist today.