Upstairs always much warmer.

[mscher]

We have central air in our small 140 year old farmhouse, but it is always hot upstairs, where there is 1 bedroom and 1 bath. There are roof vents, for the very tiny attic above.

At first I thought is was just the heating/AC " retrofit", which appeared to be installed by the Frankenstein heating Co., but my sister, who has a house, 20 years old or so, says her upstairs are always uncomfortably hotter, also.

I was going to work with duct booster fans, etc. to push more air (all the way acroos the house), but it's hot and i have no time, so we just installed a small window AC unit.

This is the first house I have ever lived in that has central AC.

Is this a common problem with 2 story homes and if so is ther a god way to correct it?

 

[JB]

Re: Upstairs always much warmer.

I am not a HVAC guy, mscher, but I have had a few 2 story homes. One was about 60 years old and the other even older. The old, old house had a serious insulation update and a well ventilated attic. It was usually comfortable upstairs.

The other house, and every other 2-3 story house I ever lived in was warmer in the upper floors.

 

[BuzzStPoint]

Re: Upstairs always much warmer.

Do you have any free flow (Exchange) ducts in the home? Not sure if newer homes have them, but older homes (like mine) have a duct upstairs that leads to the main floor. It does nothing but help circulate air.

That might be something to look at. Otherwise you may need to look at the ventilation of the home.
When the AC is on. can you feel a good amount of air coming through the upstairs ducts? You may need to restrict some lower level vents to allow more air upstairs.

 

[rbh]

Re: Upstairs always much warmer.

When was the last time you had your ducts cleaned???

Remember cold air is heavy're than warm air, so as was said route more cold air to the upstairs and as it cools it will begin to fall back down stairs.

(have you tried those bamboo outside shades for your windows, stop the light/heat before it goes threw the glass)

 

[Boomyal]

Re: Upstairs always much warmer.

I'm in a 23 y/o well insulated 2 story house in the PNW.(read that cloudy 9 mo's/year) There are only two rooms upstairs (plus a landing) and they both have skylites in them. The rooms are basically back inside the full hip roof. The house has central air (heat pump). It is always warmer upstairs whether it be summer or winter. Heat does rise, you know.

To try to help the summer time heat difference, I put reflective mylar on both the skylites and installed one huge thermostat controlled attic exhaust fan to move the hot air out of the attic that surrounds the rooms. Both of those things have made a noticable difference but I think the only real solution would be to go with one of those newer zone heat pumps. Those are supposed to be pretty efficient at cooling different rooms to different temperatures.

 

[CobiaXL]

Re: Upstairs always much warmer.

Move a thermostat upstairs....Problem solved.

 

[Boomyal]

Re: Upstairs always much warmer.

Move a thermostat upstairs....Problem solved.

Oh, boy, that'll freeze them out downstairs! .....and run up their utility bill thru the roof.

 

[Raystownboater]

Re: Upstairs always much warmer.

Old farmhouses arent known for their attic insulation. The best way to handle the issue is Insulate and add a power roof vent. The power roof vent will actually suck all the heat out of the second floor and you'll notice the air conditioner is running less. The government is offering huge discounts and refunds for energy saving improvement done to your home. Some projects will even end up costing you nothing after tax breaks and refunds.

If you want immediate relief, close the downstairs vents to force the air upstairs only. You'll notice your condenser running more but that will even out the upstairs and downstairs, as far as temp goes.

 

[stevenj]

Re: Upstairs always much warmer.

As stated hot air rises, attic fans help, the biggest thing to check for is sufficient return air from the second floor back to the furnace/air handler.
If there is returns upstairs make sure they are not blocked for 1 thing. We would in a lot of houses move the return air grilles from the floor level up as high as possible on the wall, there may be a wood stop above the grille in the stud space that we would have to get creative to remove ,but most can be done. In a few cases if no returns are upstairs we would luck out and have a laundry chute that we could convert into at least a centralized
return up stairs and that would help. Other than that,try running the blower continuous,that may help with stratifacation of the air.

Good luck
Steve

 

[lckstckn2smknbrls]

Re: Upstairs always much warmer.

+1 on the power roof vent.

 

[Nandy]

Re: Upstairs always much warmer.

I seen that problem in every place I have lived with 2 story. In my place I equalize the ducts at the plenum. I have markings for winter and markings for summer so I know where to move the level and I am in and out in minutes. Then each room can be better controlled by whoever lives in it by closing/opening the registers. My problem upstairs is mostly the master room, that one's duct is wide open for summer and close to shut on winter time. The 2 big windows get all the morning direct sun and most of the evening sun (direct then indirect). Once it gets dark it cools good. We are going to put wood blinds and thick curtains to see if that help. We cant do anything to the facade of the house or outside as we live in a hoa neighborhood.

 

[sublauxation]

Re: Upstairs always much warmer.

I've got a 1 1/2 story house from the 40's. A couple years back I added a ton of insulation and it helped a lot. The side attics still get pretty warm so I'm considering adding a power vent. The upstairs now stays only about 3 degees warmer than downstairs unless it's brutally hot out there. Another thing that helped is putting a fan in front of the vent. I ran a return vent but haven't gotten around to hooking it up yet, but that should help some.

 

[hrdwrkingacguy]

Re: Upstairs always much warmer.

Where are the returns in this house? Downstairs would be my guess...

Not to insult anyone intelligence but an air conditioner does not blow cold air into a house...It uses the supply air to pressurize a room to move the heat out of it, and back to the return that is under negative pressure and to the indoor coil to remove the heat from it...The air that comes out of the supply registers isn't "cold" it is air that gave up its heat to the refrigerant in the system...

If you don't have enough pressure out of the registers upstairs, and the return is a long way away, the upstairs will always be hot...If you have to right type of registers you can close down some(depending on design of the house) close to the return and drive more air upstairs...

Describe with a little more detail how the system is laid out...

 

[Brewman61]

Re: Upstairs always much warmer.

Thermostat will regualte the temperature for the area it's in. Typically main or first floor. When main floor hits set temperature, a/c shuts off. T'stat doesn't know what temperature is upstairs. Since warm air rises it's usually going to be somewhat warmer upstairs than down. I have a modern two story with air returns in every room there is a duct, and we still have the issue. The ultimate solution is zoned heating/cooling, which is pretty expensive, especially to retro fit. Moving the T'stat upstairs will reult in a the lower level being cooler than the set temperature- the opposite issue. And if you live in a winter climate, you'll have a chilly main level during heating season. What I do is to make sure all registers on the upper level are fully open, and partially close the registers on the main level, so in theory more air is pushed upstairs while the a/c is running. You might also consider running the fan full time, that may more equally distribute the air in the house, instead of the fan only running with the a/c.
If it's really intolerable, install a ceiling fan in you bedrooms, or consider one of those portable a/c units, to get you thru the worst of the hot nights.

 

[lncoop]

Re: Upstairs always much warmer.

Hardworking, I just noticed your location. I bet you are a hard-working A/C guy. Something in your response struck a chord with regard to my situation. We have a split level ranch built in '65, 1950 square feet. Very typical house from that era; three bedrooms, large master, other two smaller. If memory serves we have a 2.5 ton condenser. The upstairs return is near ceiling level and directly above the thermostat in the hall. At some point the master bedrooom was enlarged quite a bit and there's a significant (never measured, but very noticeable) temperature difference between one side of the room and the other. There is pretty good airflow out of every register in the house (especially when we close the downstairs registers, which we do most of the time in the summer) except the one on the newer side of the master. I can barely feel it over there. Most of the upstairs is comfy, but our bedroom doesn't cool down for a long time, usually into the night. The ceiling fan helps, but I know things aren't right. We have decent insulation and lots of attic ventilation (soffit vents and turbines), but I've never felt our airflow was adequate, especially in the master, and your comment convinces me further that that's the problem, but I don't know what to do about it.

 

[greenbush future]

Re: Upstairs always much warmer.

I have a tri-level and added central air about 3 years ago. Because of the lay-out of my home the cold air tends to fall down to the lower unit too. I have about a ten degree difference from upstairs to the lower level family room. If you can place a sheet at the top of the stairs or if you have a door, close it, and the cold air will stay up there a bit longer and you may see a change. I deal with the same issue in the winter too with heat. I also have a separate AC thermostat and it is located upstairs in the bedroom.

 

[hrdwrkingacguy]

Re: Upstairs always much warmer.

Keep in mind I have been sick the last few days, but it seems like this thread has three separate stories going on at once...Here is my answer to all three at once...

As far as the AC unit is concerned, the faster the air moves through the unit, the more sensible heat is removed...Higher fan speeds will produce more volume at each register and help "drive" the heat to the return where I can do its thing...If you live in an area where humidity is a problem higher fan speeds don't do as much to dehumidify...So slower fan speeds are the answer...

If you have a situation where your duct system is to big(volume wise) for your house you can speed up the fan by moving a wire in the unit...usually common is white or purple and the speed taps are red=low,blue=medium,black=high...if you are set on low speed in cooling you can raise it and see what happens...

The bottom line is you need to be able to provide enough volume to pressurize the registers, but move the air in the return slow enough to allow the unit to pull the latent heat(humidity/energy in the air) out...

What I would look to do is point the supply registers at the outside walls or windows and let the return draw the air back to the center of the house...

 

[Tim Frank]

Re: Upstairs always much warmer.

As far as the AC unit is concerned, the faster the air moves through the unit, the more sensible heat is removed...Higher fan speeds will produce more volume at each register and help "drive" the heat to the return where I can do its thing...If you live in an area where humidity is a problem higher fan speeds don't do as much to dehumidify...So slower fan speeds are the answer...

I don't think your opening statement is correct....but you recovered brilliantly... ...then I noticed your location and realised that you have probably heard of humidity, but may never have witnessed it first hand.......When the bathroom toilet is sweating, you have got to get that latent heat first.

Given that the original problem is in Indiana, and heating is a significant issue for at least 3-4 months/year, there are a few items that are usually the main culprits.

1) Duct system. Ideally the heating and cooling ducts would be separate...other than a few commercial systems, I have never seen that in a residential installation.
Duct outlets and inlets are usually on the floor....maybe some cold air returns are on the wall. For heating, the best layout would be hot air inlet on floor, cold air on opposite side of room on floor. A/C works best with conditioned air feeds in ceiling, hot air returns on opposite side of room....in ceiling.
Given the reality of how residential HVAC systems are installed, the only cost-possible work-around/fix is a ceiling fan ...you can reverse the fan spin as appropriate for the change from heating to cooling.
You want as close as you can get to the same temp at the ceiling as the floor.

Running your distribution fan 24/7 also helps to reduce stratification.

2) As important as insulation in the attic, is ventilation...the goal would be to have less than 5 degree temperature difference between the attic temp and the outside ambient temp. Adding ventilation is fairly cheap if you need more.

3) Most homes never have had a proper air-balancing done on their duct system. Some ducts don't even have balancing dampers. This is another fairly inexpensive action, and worth the price. You can also retro-fit a duct fan in the longer duct runs to help out if required...but all the other corrections should be tried first.

 

[hrdwrkingacguy]

Re: Upstairs always much warmer.

I don't think your opening statement is correct....but you recovered brilliantly... ...then I noticed your location and realised that you have probably heard of humidity, but may never have witnessed it first hand.......When the bathroom toilet is sweating, you have got to get that latent heat first.

If you understand the concept I am trying to explain it is absolutely correct...Air changes per hour is what takes care of sensible heat in any space...Units are designed to turn over the volume of an area 7 times an hour...So saying faster air speeds when your turnover rate is less then 7 times an hour will accomplish removing sensible heat from the air...If the speed of the fan is to slow it will be better at drying the air out, but wont be enough to make the house comfortable...There is a balance that has to be accomplished when a system is designed...

Lots of commercial customers tell me that its "hot" in their office...When I get out my psychrometer it tells me their space is 74 degrees with 58% humidity...Slow down the speed of the system and adjust the charge a little and problem goes away...Opposite is true when people get a shock from static electricity in their office...When I check its 74 degrees with 16% humidity, raise the fan speed and it goes to 35% or so and they are gtg...

 

[sw33ttooth]

Re: Upstairs always much warmer.

i've done some insulation work with blowing and i put it in knee deep with in 6 months its gone down 6 inches with in the year its down a foot/ so with in 100 years its way past its age and should be done again. however even after you do this it will still be a 5-10 degree differnce most likely since hot air raises.