Why is there a massive temperature difference between floors?
Multi-level HVAC setups frequently suffer from severe temperature gaps, leaving one floor freezing while areas of the lower level fail to cool. Because the system's thermostats interact across levels, trying to match temperatures can prevent the downstairs unit from running and leave the house completely unbalanced.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Setting the upstairs unit 4 to 5 degrees higher than the downstairs unit
- 2Closing the vents in the basement altogether
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“If the upstairs AC is set as same temperature as downstairs, then the downstairs unit won't run, and the upstairs becomes an icebox.”source ↗
“Areas of the downstairs don't cool.”source ↗
“We recently moved into a house we were renovating and are trying to diagnose a significant temperature difference between levels.”source ↗
“the thermostat was set to 69°F, but the upstairs remained around 74-75°F while the lower levels of the house were already quite cold.”source ↗
Where this came up
People with this problem also raised
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- 19Why is one bedroom getting way more air than other rooms?
- 3Why is my attic apartment so hot in summer and cold in winter?
- 6How to cool a house without ducts or ugly wall units
- 2Can you service an HVAC system with leak seal in it?