(417) 241-5687 24/7 Emergency Service
If the upstairs of your house is unbearable in summer and the downstairs is fine, nothing is broken. The system is doing exactly what it was told. The problem is who is doing the telling.
Redeemed HVAC & Plumbing covers north Republic for heating repair, air conditioning repair, furnace service, installation, HVAC maintenance, ductwork, thermostats and plumbing. We are based in Republic, not visiting it, and we are open 24 hours. Call (417) 241-5687.
This page is about the one fault we see most in two-story homes here, because it gets misdiagnosed as a sizing problem and solved by buying equipment that cannot fix it.
Because warm air rises and your thermostat lives downstairs. That is the whole of it, and it has a name: the stack effect.
Air in a house behaves like air in a chimney. Warm air is less dense, so it drifts up and leaks out at the top of the building, through ceiling penetrations, attic hatches and recessed lights. That outward leak at the top pulls replacement air in at the bottom, and the house develops a slow continuous upward current whenever there is a temperature difference between inside and out.
In summer the current carries your cooled air upstairs and out. In winter it carries your heat up and out, while cold air is drawn in around the lower doors and floor. Either way the second floor and the first floor are living in different conditions, and the thermostat only reads one of them.
So when the thermostat on the first floor is satisfied, the system shuts off. It does not know the upstairs is four or five degrees behind. The equipment is working. The measurement is in the wrong place.
This is the expensive mistake, and it is an easy one to be sold.
The reasoning sounds right: upstairs is hot, so buy more capacity. What actually happens is that a larger unit satisfies the downstairs thermostat faster. Shorter cycles mean less total runtime, and runtime is what moves air upstairs at all. The second floor gets less conditioned air than before, not more.
It also costs you humidity control. An air conditioner removes moisture by running long enough for water to condense on a cold coil and drain away. Short cycles never get there, so the house ends up cool and damp, which feels worse at the same temperature. Upstairs, where the moist air has collected, feels worst of all.
The fix is longer, gentler runtime and better distribution, which is the opposite of more capacity.
In rough order of how much they return for what they cost.
Notice that four of those six are building work rather than equipment. That is usually how it goes, and it is why we measure before quoting a machine.
Two readings separate a stack effect problem from a real equipment fault, and they take one visit.
First, temperature at the supply registers upstairs and downstairs with the system running. If the air arriving upstairs is the same temperature as the air arriving downstairs, the equipment is fine and you have a distribution and leakage problem. If the upstairs air is noticeably warmer, you are losing it in the ducts on the way.
Second, static pressure across the air handler. High pressure means the ducts are the limit, and no amount of new equipment will get past them.
Add a simple room-by-room temperature log over an afternoon and the picture is complete. A technician who takes those numbers can tell you which of the six items above applies to your house. One who does not is guessing, and guessing on this problem is how people end up with an oversized air conditioner and a hot bedroom.
We are a heating and air business and a plumbing business out of one Republic address, which in practice means one call instead of two companies for a house in southwest Missouri where the furnace and the water heater sit in the same basement.
Our listing is open 24 hours, seven days, including holidays. That is not a marketing line, it is what the profile says and what we answer.
Before you call at 2am, three things are worth checking because they are the most common causes and you can rule them out in two minutes. The thermostat batteries. The furnace switch and the breaker, both of which get knocked. And the air filter, because a badly blocked filter will shut a furnace down on a safety limit and it looks exactly like a dead furnace.
On a high-efficiency furnace there is a fourth: a blocked condensate drain trips a float switch and stops the unit. Same symptom, simple cause.
If none of that is it, call (417) 241-5687.
Why is my upstairs so much hotter than downstairs in Republic?
Warm air rises and leaks out through the top of the house, which pulls replacement air in at the bottom and creates a constant upward current called the stack effect. Your thermostat is downstairs, so when the first floor reaches temperature the system stops, and the second floor is left several degrees behind. The equipment is usually working correctly. The measurement is in the wrong place.
Will a bigger air conditioner fix a hot upstairs?
No, and it usually makes it worse. A larger unit satisfies the downstairs thermostat faster, so it runs for less time, and runtime is what moves conditioned air upstairs. You also lose humidity removal, because short cycles never run long enough to drain moisture off the coil. The answer is longer runtime and better distribution, not more capacity.
What is the cheapest thing that actually helps?
Air sealing the top of the house: the attic hatch, recessed light housings, and the penetrations where plumbing and wiring pass through the ceiling. The upward current can only pull air in at the bottom if it can leak out at the top, so sealing the top attacks the cause. It is building work rather than HVAC work and it costs far less than equipment.
Do I need zoning or will a damper adjustment do?
Start with balancing, because it is free to try and it tells you how much headroom the duct system has. If sending more air upstairs in summer gets the two floors within a couple of degrees, balancing was enough. If the second floor still cannot keep up, it needs its own thermostat, and that is zoning.
Do you cover north Republic for both heating and plumbing?
Yes. We are based in Republic and we run heating, cooling and plumbing out of the same business, so a furnace problem and a water heater problem are one call rather than two companies. The listing is open 24 hours.
How quickly does the stack effect show up in winter?
It runs all winter, just in reverse of how people picture it. Heat collects upstairs and escapes through the ceiling, while cold air is drawn in low, around doors and at the floor. The usual winter complaint is cold feet downstairs and a bedroom upstairs that is too warm to sleep in, which is the same current doing the same thing.
A visit should end with the supply temperatures, the static pressure reading and a plain statement of whether your problem is the equipment or the building. That is the version you can act on.
Call (417) 241-5687. For everything we cover across town, start with our heating and cooling work in Republic.
(417) 241-5687
Open 24 hours, 7 days a week, including holidays.
Two tune-ups a year on every system you own, 10% off all repairs and priority scheduling, from $14 a month.
Approved financing spreads the cost of a replacement, so the timing of the work is your decision rather than the equipment’s.
A heating or cooling problem leaves you guessing at both the cause and the price. The diagnosis comes with the readings behind it and the quote comes in writing, itemized, before any work starts. Call (417) 241-5687.