Do you have a hot upstairs during the summer air conditioning season? I’m sure it is of little consolation for me to tell you that you are not alone and that this is one of the most common air conditioning problems we hear about. What should you do if your upstairs is much hotter than the downstairs? Do you need a more efficient air conditioner or a larger air conditioner? Before I suggest solutions, let’s discuss why the upstairs is so uncomfortable during hot summer weather.

Cooling the upstairs of a two-story home is a challenge for many reasons. The downstairs is usually closer to the air conditioner fan and it gets most of the airflow. The thermostat is usually downstairs, it senses the plentiful cool air in the downstairs, and shuts off the air conditioner before the upstairs is cool. The upstairs has a hot attic above it. The ducts to the upstairs are commonly undersized considering the extra distance from the fan.

Another very significant factor is when a home has any two-story room (foyer, great room, etc.) that allows much of the downstairs heat to flow into and gather in the upstairs. Worse yet, homes with an upstairs open loft or balcony may have sitting areas in this heat collection zone. The cool conditioned air delivered to these open rooms will often fall to the downstairs via the quickest route possible and add to the premature cooling of the downstairs thermostat.

Here is the bad news first. A new high efficiency air conditioner or a larger air conditioner will not help this imbalance. Do not accept a sales proposal based on this claim. The most common reason for the hot upstairs is the lack of air flow to the hot rooms. They are normally farther from the furnace than the downstairs rooms and need larger ducts. If your ducts are accessible, we may be able to make some changes to help cool your upstairs better. Good duct design during home construction is what Precision Comfort Systems is known for. We can apply our new home design experience to your home if your ducts are accessible.

Here are some tips if we cannot change the duct system:

  • Close all the blinds upstairs during the day.
  • Close basement registers. Close the downstairs registers closest to the thermostat but do not close all the downstairs registers.
  • Try running the AC fan in the “continuous” mode. If it helps great, but if it is only a slight benefit, remember that the fan is costing a bit more to run all the time.
  • In the rooms that are two stories high and open to the upstairs, try a ceiling fan to counter the upward heat flow. In other rooms, use ceiling fans only when you are in the room and only if they help. They cost money to run.
  • Check your attic insulation. Many attics need more insulation added after many years of storage, maintenance traffic and sometimes even weather damage to the old insulation.
  • Call Precision Comfort Systems to see if your home is an easy candidate for a zone system or maybe even a new, second air conditioner dedicated for the upstairs. This is the ultimate fix if your home layout allows it.