The floors need to be zoned separately. You can accomplish this a couple of ways.

1. Remove your current HVAC system (all of it). Size it to appropriately handle the upstairs area.

Install another HVAC system to handle the down stairs area. Because the current system serves this whole house it is too big to keep. (size wize it can cause a whole lot of additional problems if you try to keep it and install another HVAC system for the down stairs or vice versa. )

Problems with this choice include: money (cost), lack of space for the equipment to fit.

2. Reusing equipment and installing what is called HVAC zone system. Requires knowledge to pull this of properly. Most zone systems I've seen cause more problems. This option should be less costly than option 1, provided it is done right otherwise it will lead to the demise of your current HVAC system.

You won't accomplish this task any other way because:

HVAC is science. Hot air rises, cold air falls.

Another option: sell this house and buy another one that is 1 story. If a single story house is expansive (large sprawling floor plan) you can have similar problems. HVAC design is typically the problem here.

There are no free lunches when it comes to HVAC design.

Things that cause additional problems in HVAC: High ceilings. They mostly do this to sell you. Because the looks are grandiose makes the house look high end. Walls of glass... you're paying for that 'view' more ways than one.

Homes are mostly sold via "looks". You don't realize comfort until after you move in and summer shows up.

My approach is to tell it like it is, not here to tell you what you want to hear. If you're old enough to own a home, you're old enough to handle the truth.

PS: closing vents off is never recommended. It causes more problems than it cures.

I service the Katy, Texas area.

Austin Air Companie - "If you're old enough to own a home, you're old enough to handle the truth"? Incredibly unnecessary and unprofessional. This is literally a discussion and question forum and nowhere in my wording did I suggest that I was some entitled brat looking for a "free lunch" after ignorantly purchasing a home based on fancy upgrades and no common sense. We had an HVAC technician out this week and he was here very briefly and told us we should close the vents to the lower level to force the air the upper level or put up a door to the downstairs so the cool air wouldn't fall back down as easily (which I stated wasn't an option due to design). I was simply looking for the input of someone who may have encountered a similar situation, which is the purpose of this site. I apologize for whoever in your path recently caused you such disdain recently that you needed to react this way to an appropriate question placed in an appropriate forum.

To anyone else needing more information...

Our home is 2400 square feet, built in the 50's with AC and ducts installed after renovations started taking place. There are no vaulted ceilings, glass walls or anything fancy of the like. We also moved in the summer of last year and went through two months of summer heat without the lower level being so intolerably cold. If improper duct installation is the culprit, perhaps when the time comes to replace the AC unit, we will note that a large project will have to be undertaken. A family visitor had mentioned the ducts shouldn't have been done the way they were. Though it wasn't a problem last summer, perhaps with these aggressive heat waves we've been getting it's only now a serious enough temperature to show it's true colors.

Where are you located and what temperature setting on the thermostat? Does the house have a basement and is that where the furnace or air handler is located?

The problem is you are not getting sufficient air flow to the second floor due to undersized duct work. You need to explore how feasible it is run additional supply ducts. They could be hidden inside a close or you may be able to build a chase in a corner of the room to hide it.

Have you checked how much insulation is in the attic? Adding insulation will lower the heat load and make it easier to cool the second floor. Keeping blinds closed on south facing windows will also help.

Any easy fix would be adding window AC units in some of the second floor rooms. It is not an ideal solution but it will help the problem.

It might be possible to create two zones with your current system. But you need to find someone who is good at zoning. However even zoning may not solve the problem is the duct work is undersized.

Mike-we're in Minnesota and currently experiencing a heat wave. Yes the furnace and AC handler are in the basement laundry room, that level (aside from laundry room) is finished but I believe the AC was installed prior to finishing the lower level. Our thermostat on the upper level is set to 70, the temp states 70 and feels right upstairs. There is a thermostat downstairs that reads 60, and it feels like a freezer. The downstairs thermostat apparently only controls the heat (radiant) and doesn't affect the AC. For the last couple hours I've set the fan to "on" instead of auto and the downstairs remains cold, though I noticed it has cooled the entryway quite a bit. Not necessarily wanting to keep the fan on constantly but hoping it may even some things out.

Will definitely consider an upper AC window unit if that would help. When the house was built they used a wood burning stove on the lower level for heat, and it looks like they rigged it now to where they removed a back section and one of the AC vents (of the three main from the unit) is going into this old wood burner that's been closed off to the roof and out of commission. Probably isn't performing top par...

Is the second floor only bedrooms? If so consider setting back the temperature to 75 degrees during the day when they are not in use. This will save energy and make the first floor more comfortable. If the thermostat is a programmable type then it can be programmed to go to 70 degrees about two hours before going to bed. When the sun is down the upper floor should cool down fairly quickly.

Your problem is one of the most common addressed here and unfortunately Ray, Mike and your HVAC are correct with exception to selling the house and closing off the vents. Closing off to many vents may destroy your blower motor or freeze up the cooing coil which may destroy your A/C compressor.

A somewhat crud but effective temporary solution would involve buying a portable ventilation fan similar to this Fan and run it from the lower level to the upper in the stair well during the worst of the heat. Just a thought but did you have any large shade trees removed this year especially on the west side of the house?

Another quick fix to look at are your curtains. Solar gain through the windows can be brutal so it's worth a look. Sorry I can't help you much more and you're not alone.

Mike-the second floor is pretty much the main level. Our entryway is on the ground floor then it splits upper and lower. So upper level is three bedrooms, kitchen, dining, living room, bathroom. But we will try to set the heat higher when possible during the day. Luckily in MN extreme heat isn't usually an issue for very long.

Kevin-Thanks, I will definitely leave the vents open since I've seen this isn't really a solution. Our shade trees are pretty much on the south side of the house. West side is the garage, then it slopes down and there are a lot of trees down in the yard but none that really shade the structure. Perhaps some appropriate landscaping is in order. On very hot days like these, we have kept all the curtains closed, but some of the curtains probably need to be thicker to be more efficient.

Some day we may be ready for a full ventilation overhaul, but not this day ha. Eventually we will see to it that it's done correctly, but thank you all for your suggestions in the meantime. I'm sure we will try them all!

A solution is likly possable but it will require someone that know's how to find it. "Someone" is normally a well trained technician that's willing to try ( increasing difficult to find) or in exceptional cases a dedicated homeowner with a mechanical mind. I have never liked for customers to tell me what I should do based on what they found on the net so I certainly don't tell people what they should have their tech do. Are you a gearhead or have one willing to help you with this? If so I might be able to help.

Most HVAC systems have dampers on the ductwork. While increasing resistance to airflow by closing down the dampers some isn't the best thing for your system, they can take a certain amount of adjustment before any harm is done. Don't "close off the vents/registers" - they will leak air, whistle and be generally noisy. But you can adjust the downstairs damper in the summer to reduce airflow there (and therefore increasing cold aid deliver upstairs). You may need to re-adjust your dampers in the fall to allow more warm air back to the downstairs.

If you don't have dampers on the ductwork, you can choke off the airflow downstairs with a 36" zip tie. This isn't as flexible as a damper but works just as well (assuming you have 8" flex ducts).

"If you don't have dampers on the ductwork, you can choke off the airflow downstairs with a 36" zip tie."

Say wut? Tell us how that works,I've never heard that before.

Say wut? Tell us how that works,I've never heard that before.

It won't work. Once heating season begins everything flips. Remember hot air rises cold air falls?

That lower level will still be too cold in the throws of winter.

Design problems are fixed by redesigning the HVAC system (properly). This can include the equipment as well as the duct system among other things.

Your home is one of the most valuable assets you own. Hard to imagine that the way most people treat it. Yet HVAC design isn't a parameter that assigns value to a house. It's typically all the crap that makes you feel uncomfortable. Tall ceilings, walls of glass, age (not designed for cooling because cooling didn't exist when the house was built.)

HVAC operates well or poorly on the sum of all the parts. It should work well in any weather any mode (heating or cooling), but design (an invisible ingredient) is primarily what is responsible for how well or not so well it works.

People always want to believe there is some "simple fix" to design problems. They will spend billions of dollars on gadgets, waste money on changing brands all the while the design is the real problem.

The design is the most complicated aspect of the HVAC system, but often ignored as the problem.

You put a long zip tie around the flexduct and tighten it until the diameter of the flexduct decreases about 25%. Its commonly done by "pros" to balance the air throughout the house if they didn't install dampers. Not the best solution but it does work.

Zip ties sound like something houzz advisers can add to their bag of tricks as a way to balance airflow without closing those pesky vent dampers. I've always been curious how pros handle it. What a rip off,install a 50 cent zip tie and charge customer $250.

You put a long zip tie around the flexduct and tighten it until the diameter of the flexduct decreases about 25%. Its commonly done by "pros" to balance the air throughout the house if they didn't install dampers. Not the best solution but it does work.

Define work. I would never do this. "commonly done"? Uh, no. I would never do it. Not even in a house I own.

I consider myself a pro. A redesign is a redesign.

I have one rule I live by: It has to work. I don't view this as something that would work in an extreme climate (either hot extreme or cold extreme)

Mild climate? maybe. But I still wouldn't do it.

I service the Katy, Texas area.

"I wouldn't do it". Just because you wouldn't do it doesn't mean it isn't commonly done.

"Define work". Works like a damper would. I take it you don't like dampers, either?

OP, as I said, this isn't particularly flexible and might not work for all season, but it is reversible.

"I service the Katy, Texas area."

Why do you feel the need to include this - other than more spam?

The OP is in Minnesota. Why do you attack his very asking for advice on a problem he has.

They say the proof is in the pudding but it look's like op went awol so we might never know if zip ties fixed it. Hopfully others with this all to common problem with two stories will try this summer and let us know. I don't know if it's the same but a man crushed my ductwork while crawling around the attic pulling phone lines and it definatly resulted in 2 rooms not cooling like they had previously. OMG,can you imagine keeping your smart phone on charge 24-7 and dragging the cord as you moved from room to room while on the phone? You kids have it good now days.

"I wouldn't do it". Just because you wouldn't do it doesn't mean it isn't commonly done.

"Define work". Works like a damper would. I take it you don't like dampers, either?

OP, as I said, this isn't particularly flexible and might not work for all season, but it is reversible.

Commonly done again? I've been doing this for 26 years, never seen or heard of this once. I live in the land of "flex duct". Works like a damper would? Then why not use a damper?

I don't like dampers either: oh for joy. Depends on what kind of damper you're talking about. Manual? Automatic? (You pay for both in more ways than one -- take a shot at it.) Pay once for automatic (**parts knowledge required there is absolute garbage out there**) --- pay for manual damper, keep paying to readjust it all the time or in time for you to have to do it. (design remember?)

Stax -- this is for you man. (Just because this is a minnesota thread, doesn't keep me from seeing it... welcome to the internet It's 2021)

It looks like an attack, because that's what truth does. You can run from the truth, or you can face it head on. I choose to face it head on. Cut to the chase right up front, never beating around the bush. Either you like it or you don't. I don't care what you think. I don't appologize for delivering the truth, just because someone's perception / feelings of the matter may get hurt.

Imagine going to the doctor, saying you have these pains expecting all you need is a "pill" to fix your ailments. The doctor not wanting to hurt your feelings comes back tells you to take this "pill". A few months later the pain persists and gets worse. You go for a second opinion, the new doctor tells you that it's cancer and unfortunately it's spread and inoperable. All because the first doctor was in business of just telling you what you want to hear.

I service the Katy, Texas area

Looks like this post has exhausted all sense of usefulness.

sktn77a
Looks like this post has exhausted all sense of usefulness.

So should everyone just "Zip-It" ?

When I was in the business I carried a screwdriver, hammer and string. What I couldn't screw up or beat up I could just tie up. Never thought of zip ties.

HVAC contractor's business card read's, "Call me first. If you call someone that screw's it up before you call me I'll have to charge for screwing it down before I can fix it".

Looks like this post has exhausted all sense of usefulness.

yep another system goes into the dust bin of never working properly, because people don't realize the importance of HVAC system design think some secret system adjustment is going to fix a design problem.

Been there, done that.

Let's all stand around and sing Coom By Ah.

Now you know why I ripped the bandage off, on the very first post. Tough love.

“Let’s all stand around and sing Coom By Ah.” Did you mean “Kumbayah,” pidgin English for a plea to God to “come by here”? From the Black spiritual in which “someone is crying” means people suffering under Jim Crow laws? Bad enough that such a meaningful song has been co-opted as a put-down for compassion, now we’re sneer spelling it too.

I am not a HVAC expert, but it seems some simple questions were not asked.

I lived in Southern California, inland desert, where it got quite hot in the summer and cost of electricity was the highest $ per therm in the country. We had 2 window AC units and had to manage to maintain livable conditions without running them day and night.

Things that really helped regulate the temperature were adding insulation to our attic and adding whirlybird fans to the attic. We used ceiling fans to help circulate the air and old fashioned window fans to direct air flow from the rooms with AC to the non AC cooled rooms unless it was really hot (106+) when we shut those rooms up and lived in them instead of the rest of the house.

We also had window film that reflected heat from our windows and blinds on the south side of the house.

It seems to me the same logic would apply here - you need to stop the heat from penetrating the house and then try to move the air and keep it moving between the two floors.

I have seen vent fans that boost air flow from the HVAC Vents. Would it be possible to add a few vents between the 1st and second floor that are not attached to the HVAC System, but have fans that draw the cold air from the downstairs into the upstairs?

@Austin Air Companie - Being honest and direct can be accomplished without brutality and definitely can be accomplished without using terminology that can be construed as racial slurs.

Prior to the Civil Rights Movement racial slurs were much more socially acceptable than they are today. But it was always a way to intimidate and oppress others through fear. (How did a 6 person household manage to oppress and control 100 slaves?)

Today this is no longer socially acceptable and those using racial slurs are generally only people who lack intelligence. It doesn't enhance any of your arguments, but generally just lowers people's opinion of you.

You really should have apologized for using offensive language and removed the language from your post instead of digging your heals in and trying to justify your bad behavior.

Kids do this, not adults. Don't do your homework, get a bad grade, scream and cry and say the teacher hates you. Adults shoulder the responsibility and modify their behavior.

I lived in Southern California, inland desert, where it got quite hot in the summer and cost of electricity was the highest $ per therm in the country. We had 2 window AC units and had to manage to maintain livable conditions without running them day and night.

It's a nice thought Jennifer, but desert conditions are considerably different than wetter hot climates due to humid type heat. That's why those that live in the desert say: "Well, at least it's a dry heat."

I've lived up and down the mid central US / the gulf feeds the central US with blasts of humidity from time to time... completely different than desert conditions.

I do realize our circumstances were different. Have to run a dehumidifier in my current basement (Central PA) and needed to run a humidifier in CA. Could also open windows at night and run fans to cool the house in the summer and do the opposite to warm the house in the winter.

But I don't understand how the general concept of insulating a box and keeping the cold air in and the hot air out and circulating the air that is trapped inside would be different.

When I think about this isn't it similar to how our fridge/freezer works - keeps the cold air trapped, one fan that pulls warm air out of the fridge and another fan circulates air over the coils and cools the air inside the unit? If the seal isn't good or the fans don't work your fridge/freezer doesn't stay as cold as it should.

Mama thanks for the bit of history. Taj Mahal wrote "Needed Time" with a similar message and Lightnin Hopkins recorded it for the movie Sounder. I saw Jim Crow Laws in living color from childhood until they ended when I was an adult in the 60s. Currently some say the laws never ended, some say they never existed and I say the majority of both have no idea who Jim Crow is/was and much less what laws carrying his name did or did not say and do. Apposing views exist today because same as people posting on houzz,they are acting on what they have been told rather than taking time to find the truth. I would willingly forego today's comforts to return to 100f+ days under Texas sun if everyone who make's their voice heard,cast's a vote for a law or candidate or slander's apposing views went to spend time with me before taking their actions. I truly believe both sides of the issue would act more meaningful having just come from 2 weeks in a cotton field working along side their opposers. Case in point,I inticipate this will be censored eventhough I never took one side or the other or mentioned which side is right or wrong. On the outside chance I'm wrong,I aurge others to remain neutral on the subject. (neutral with comments here,not neccessarly in life).

Back to our regular program. Jennifer I do believe your comments make as much sense as any and alot more than the majority. I feel like i could guide you to a solution if this were your situation. Unlike Smith Farms,I believe you would make an effort instead of cut and run when a silver bullet wasn't offered. Scroll to secound comment in this thread then tell me what more Smith might be expecting.

To the heart of back and forth over poor designs and overcoming them. Who design's these systems,homeowners or contractors? In the event of an installation with poor design,who's the fool for not knowing or caring how to straighten it out,homeowners or contractors. There's no doubt in my mind who deserve's to have their heads held under water until they get their act straight.

Thanks everyone, sorry for the delayed response as it was difficult to keep up with multiple people going back and forth on what would or wouldn't work, we were out of the house all day yesterday and one of the kiddos is sick.

To reiterate, I was not looking for some miracle solution to this issue, rather something to help alleviate the ice box downstairs for the brief time the weather is extreme. Extreme heat is not typically an issue in Minnesota. I was always in agreement that the duct system is the main problem and a complete renovation of the ducts would be the complete solution.

So what's been done thus far via suggestions - We've kept the thermostat upstairs higher than usual so the air doesn't have to work so hard and kept the overhead fans on the upper level going. I only slightly closed all the lower vents to reduce the air being forced to that level. I angled a strong blowing fan from the lower level going up the stairs into the entry. If nothing else it really cooled the entryway down. The temperature on the lower level came up about eight degrees and the upper level stays as cool as what we set it to, which it was doing to begin with.

Wasn't sure about the zip tie as I didn't want to damage anything, but it did bring to mind what was found a few months after we moved in. It wasn't this way during inspection but about October (which was well after the brunt of the heat) we noticed that one of the vents from the main unit (the one that connects to the lower level ducts) was pulled down from the connecting duct, causing only about half of the air flow to go through the vents while the other half poured into the laundry room. We had kept the laundry room door closed during July/August because it was chilly in there. This would explain why this wasn't really an issue last year and confirm that the previous owner knew the ducts were kind of crappy. Again, probably because they tapped into old work.

Since we are mainly on the main floor and only go downstairs to use the office and laundry, occasionally the lower family room, it is tolerable for now. I'm sure pulling the vent back down would offer similar results to the zip tie in reducing the flow (except the zip tie probably wouldn't make the laundry room cold) and hey, who wants to spend a lot of time in the laundry room anyway?

I do appreciate all the professional responses and agree that the ducts ultimately need to be redone (we will be in this house likely the rest of our lives) and will cross that bridge as probably part of a large project whenever the air conditioner needs to be replaced. We are researching the window AC units for the upper level to remove some of the stress on the system so it doesn't have to run so hard.

Kevin-Yes good point, I will have to check it out further. From records the house was bought 11 years ago as a foreclosure and a lot of it upgraded, but it seems mostly cosmetic. I am going to pull up the inspection report because it seemed pretty detailed with a ton of photos, so maybe there's something about the insulation. I know it wasn't an issue for passing code doesn't mean it's able to keep up with the heat and cold. The lower level got finished so that has sheetrock but the upper level still has plaster walls (so perhaps NO insulation?) except for the bathroom which was renovated. Probably something else that has to be addressed. -I am in McLeod County

I only slightly closed all the lower vents to reduce the air being forced to that level. I angled a strong blowing fan from the lower level going up the stairs into the entry. If nothing else it really cooled the entryway down. The temperature on the lower level came up about eight degrees and the upper level stays as cool as what we set it to, which it was doing to begin with.

Good work! I gather from this the upper and lower level are within two degrees of each other.

We are researching the window AC units for the upper level to remove some of the stress on the system so it doesn't have to run so hard.

Don't wait too long on buying a window unit. I am hearing units are in short supply. If there is only a 2-3 degree difference, I think you could close the gap by supplementing the cooling on the upper floor with one or two window units. It will also help reduce your electric bill. The savings will offset the purchase.

But I don't understand how the general concept of insulating a box and keeping the cold air in and the hot air out and circulating the air that is trapped inside would be different.

The "design" of a refrigerator is completey different from that of home HVAC system. Different concerns. Will a head of lettuce complain? I suppose you might complain if you reach in the refrigerator and the head of lettuce is frozen from being placed in the refrigerator section.

How about humidity? will you get a complaint of too much humidity in a refrigerator? I doubt it.

For a very big important reason a refrigerator is designed completely in a manufacturing setting. That box, nothing changes from transport from point A to point B. You take that box and it was designed fully for the operation intended. You merely plug it in.

When it comes to HVAC systems, the manufacturing part is limited to the equipment. The duct work design / design of the HVAC system is done outside the realm of a manufacturing setting.

Different markets / different concerns. The OP has commented this a rare event. SO who ever did this design decided it was not worth the $$ to create a better design. This occurs even in my climate. The how much money should we spend on design so we are comfortable?

People move in, discover the realities in person. It can look great on paper, once people move in and use it they way they see fit? The OP says: We mostly use the upstairs... Heat rises. And bingo why the problem exists extends to how the property is used.

If this property the first floor was used more you merely keep the thermostat on the upper level set higher except maybe at night as I guess the bedrooms are upstairs?

Adding insulation can help, but the conflict of too cold down stairs versus to hot upstairs will remain. Heat rises all day, everyday. No amount envelope insulation will change that.

Window units can help too, but these come with their own set of inconveniences typically related to noise or continually having to mess with settings. Then you'll need one for each room. In some areas you'll get a nasty letter from HOA telling you that window units aren't allowed.

Now if you're even more upset? Welcome to 2021. At least you know the truth. That's what your goal was in coming to Houzz, wasn't it?

I service the Katy, Texas area.