Will adding [air duct] returns cool the upstairs bedrooms?

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yolli71
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Will adding [air duct] returns cool the upstairs bedrooms?

Post by yolli71 »

Will adding an air return to each bedroom help cool the upstairs bedrooms in the summer?

Background:
I have always had a hard time cooling down the upstairs level of my SFH during hot summer days. I live in the DC area in a 3 level home that's about 3,500 sq ft. I have two 3 ton units for my home...one unit is for the basement and main level (air handler located in basement) and the other unit is strictly for the top level (air handler located in attic).

To help combat the problem of the heat upstairs, I decided around 8 months ago to have my attic air sealed after getting one of those energy audits. I had extra insulation added in the attic and all the hvac ducting and top plates were sealed using foam. Then about six months ago, I purchased blackout honeycomb shades for each of the bedrooms. Around 2 months ago I had an AC company come in and do one of those annual inspections/tune-ups of my AC unit...the guy said it was in great shape. And while not totally related, I needed a new roof around 2 years ago and went with a lighter gray color that had a ridge vent (didn't have a ridge vent prior).

I had high hopes for my AC this summer but as we're rounding into mid-June, I've been really disappointed in the results. I believe the air sealing helped in the winter time (kept our heat lower than usual and it was a bad winter). However, there's been only a tiny effect on the cold air...it still gets hot upstairs and is tough to cool down and we're not even in the dog days of July/August yet! My upstairs level is only about 1300 sq feet and has it's own 3 ton unit...I feel plenty of cold air blowing out of the registers so I can't imagine what the issue is.

At this point I'm wondering if adding a return to each bedroom will help? I have one return in the hallway upstairs and one in the master bedroom. I've noticed that the coolest room upstairs is the master bedroom, and while I'm sure much of that is due to the two vents, this bedroom is also by far the largest with a cathedral ceiling and two skylights. Is it possible the return in the master is what helps keep the bedroom cooler than the other 3 bedrooms upstairs?

I had one guy quote me $1,100 to install 3 returns. I had another guy tell me that adding returns won't do much to change the temperature...in fact, it might suck some of the cold air in b/c my registers are located in the ceiling (where the returns would also be located). Or is it possible I might need more insulation in the walls to the exterior of the house?

Between a new roof, air sealing my attic with additional insulation, and blackout honeycomb shades, I really don't know what else I can do.
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Re: Will adding returns cool the upstairs bedrooms?

Post by Grt2bOutdoors »

What is the temperature setting at the lower and upper floor levels? Same or different? Hot air rises, so it may just be the settings need to be adjusted upwards or down. I think my technician said to keep my first floor settings slightly higher (warmer) than my second floor setting (cooler) or is it vice-versa (not near the thermostats right now). How many returns do you have on your second floor? I have 2 returns. I have about a little more than half of your sq. ftg and 5 tons; one 3 and one 2 unit.

It's not the returns, it's the size of the vents that are bringing the cool air to the rooms, so if your bedroom has 7 inch vents and another room has 5 inch vents you will feel a difference in the air flow and cooling ability. Larger room requires larger vents. Also, are the doors to the rooms kept open or shut? Open is preferable allowing the air to circulate throughout the floor.

Are you keeping both units set to auto/on all of the time? Actually, they won't be running all of the time only should be cycling on/off when the thermostat dictates turning on/off - but my technician said leaving both units on during the day/night aids in the efficiency of cooling down the home, both units will work to keep the temperature manageable. If you shut the first floor unit off, hot air rises to the second floor, one unit is not enough to cool down quick enough - it could take hours. After I fiddled with my first floor unit temperatures, I noticed the second floor cooled down much quicker and the unit was not constantly running to keep it cooled.

I feel your pain, I just went through this exercise.
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powermega
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Re: Will adding returns cool the upstairs bedrooms?

Post by powermega »

Another couple of ideas to consider:

1. An attic fan. This will push hot air out of your attic and draw cooler outside air in through the soffits. The ridge vent you installed helps a lot, but an attic fan is an active fan to help the convection of heat in your attic.
2. A whole house fan. This can be combined with #1 above too. A WHF can draw air through open windows in the house and push air into the attic. This can cool the house and the attic at the same time. This only works when the outside temperature is below the temperature in the house. Without knowing a lot about DC's climate, I'll admit that this might not be a suitable solution for you.

I'm putting a WHF in my house this summer. I live in CO where we have cool nights and relatively low humidity.
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Re: Will adding returns cool the upstairs bedrooms?

Post by livesoft »

Fans are a good idea, but I would start with ceiling fans directly over the beds. Our home has a ceiling fan in every bedroom, the den, and the upstairs gameroom. This is pretty standard in the South I think. They are easy to install, too, since there is usually a light fixture in the middle of a the ceiling in most rooms.

Our home has two separate HVAC systems: one for the upstairs and one for the downstairs and is reasonably well insulated. There is only one "return" for each of them, but the returns are 16 in by 32 in. Keep the return filters clean, too.

Our attic has two electrical fans controlled by thermostats, so they come on only in the hot summer and not in winters. I know folks with ridge vents and windturbine fans, but we do not have those. Even with our fans, the attic is hot, hot, hot in the summer, but that's also where we have our hot water heaters, so we save on heating water in the summer.
Last edited by livesoft on Fri Jun 13, 2014 1:53 pm, edited 1 time in total.
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TheTimeLord
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Re: Will adding returns cool the upstairs bedrooms?

Post by TheTimeLord »

It should even out the temperature throughout the space and make rooms cooler when doors are closed. WHen I bought my house making sure there were plenty of return air vents was a priority.
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walkabout
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Re: Will adding returns cool the upstairs bedrooms?

Post by walkabout »

If the bedroom doors are often closed, that is probably a big part of the problem. If so, you will probably get better and cheaper results by putting a grill in each door rather than putting an actual return into each room.

livesoft has a good suggestion about the ceiling fan. Maybe I am stating the obvious, but make sure that the electrical box in the ceiling is rated for a fan (i.e. it can safely hold the weight of a fan) before you install one.
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Re: Will adding returns cool the upstairs bedrooms?

Post by AnimalCrackers »

OP, we solved a very similar problem by installing inline duct fans in the basement in the ducts that led to two offending bedrooms on the second story, one with a rheostat.

They look kind of like this: http://www.amazon.com/Fantech-FR-150-Ce ... 029&sr=1-7
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Re: Will adding returns cool the upstairs bedrooms?

Post by Globalviewer58 »

Did the energy auditor have a Home Energy Professional Certification?

Your list of improvements covers some common issues. The decision to seal the attic is made after a blower door test shows high levels of air leakage in the space. The same test performed after the sealing work will show the benefit from sealing. Do you have data to prove reduced air infiltration from the attic into the living space?

The energy audit should indicate the type and R value (fiberglass R-13 batts in the walls for example) of existing insulation in the walls and ceiling and recommend any changes. Do you know the actual values and potential for improvement?

An attic ventilation system requires intake and exhaust vents. The ridge vent is the exhaust half of the system. If you added a ridge vent, were the old exhaust vents removed? If not, the system may short-circuit the intended airflow. What vents provide fresh air intake to the attic? Are the intake vents clear of insulation or other obstacles that impede the flow of air from outside into the attic?

What conclusions did the energy auditor make on the windows installed on the top floor? The link is a good article on energy efficiency of windows. http://www.finehomebuilding.com/how-to/ ... ndows.aspx
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Re: Will adding returns cool the upstairs bedrooms?

Post by HardKnocker »

I have this problem with my upstairs also. I have returns upstairs but heat rises and cold air falls so they don't really work. They do work for heating of course.

After many years of being frustrated I have found something to help.

I place a powerful fan on the second floor landing and point it down the stairs and run it continuously on low to circulate the air from upstairs to the main floor. Now the upstairs is much cooler.

I still have window units upstairs to provide additional cooling when the rooms are in use on the hottest days if needed. They are new models and quite energy efficient.

You'd be amazed at the difference the use of the fan has made in my home. Before the upstairs air was just not able to circulate. The downstairs was cool and the A/C would shut off as the thermostat was also downstairs.

Roof ridge vents or attic roof power vent fans while important for removing moisture from your attic will not affect upstairs temps very much unfortunately so that is not a solution.
Last edited by HardKnocker on Fri Jun 13, 2014 2:55 pm, edited 1 time in total.
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Re: Will adding returns cool the upstairs bedrooms?

Post by livesoft »

^That makes sense for a single A/C unit for the whole house, but the OP has a separate 3 ton unit for the upstairs.
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Re: Will adding returns cool the upstairs bedrooms?

Post by HardKnocker »

livesoft wrote:^That makes sense for a single A/C unit for the whole house, but the OP has a separate 3 ton unit for the upstairs.
The location of the thermostat for the upstairs unit is important. Is there a separate thermostat upstairs (the sensor must be upstairs too) or is it downstairs?

Regarding roof ridge vents, if you have ridge vents you do not use power roof vent fans. One or the other but not both. The ridge vents pull up fresh air from the soffit vents by convection. Using a power roof vent at the same time disrupts the air flow. Some roofers are ignorant of this. One way to find out if your prospective roofer knows what he is doing.
Last edited by HardKnocker on Fri Jun 13, 2014 3:04 pm, edited 1 time in total.
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Re: Will adding returns cool the upstairs bedrooms?

Post by Sidney »

I second the suggestion for ceiling fans. We keep some on at very low speed year round. In the summer, I set it to push the hot air that gathers at the ceiling down; in the winter, I reverse it. Keeping the air flowing gently keeps the thermostat steady.
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Re: Will adding returns cool the upstairs bedrooms?

Post by Globalviewer58 »

Hardknocker, reference the comment about attic vent not providing heat relief, please see literature
with test results showing that properly designed and installed attic ventilation systems provide some relief from high temps in the attic. http://www.airvent.com/pdf/literature/PAVbooklet.pdf
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Re: Will adding returns cool the upstairs bedrooms?

Post by HardKnocker »

Globalviewer58 wrote:Hardknocker, reference the comment about attic vent not providing heat relief, please see literature
with test results showing that properly designed and installed attic ventilation systems provide some relief from high temps in the attic. http://www.airvent.com/pdf/literature/PAVbooklet.pdf
The benefit of roof venting on interior room temps is negligible. The air that is pulled into the soffit or gable vents and then out through either the ridge vent or power roof vent is outside temperature air. If the outside temp is 100 then that is the temp being pulled from the soffit vent under the roof sheathing and then out the ridge vent. Most power vent fans are set to activate around 110 degrees. Roof venting is mainly for moisture removal but will reduce the roof sheathing heat a bit.

I have ridge vents on sections of my roof and power roof vent fans on other sections (not connected). Both are very inadequate for cooling upstairs rooms that are insulated from the attic space. I wish they were effective but they are not.

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Last edited by HardKnocker on Fri Jun 13, 2014 3:58 pm, edited 1 time in total.
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dm200
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Re: Will adding returns cool the upstairs bedrooms?

Post by dm200 »

Where is the return for the upstairs, since you have a separate unit?

What about the upstairs thermostat?

Do you have a setting on the thermostat to have the fan run all the time? If the fan only runs when cooling, and the thermostat senses that it is cool enough, the air conditioning and the fan go off - and it may then warm up in the rooms. If you can, set the fan to run all the time - then the air will be circulated much better.

I once lived (Washington DC area) in a rental house that was a rambler (called a 'ranch' in some areas) with a walk out basement in back. The main floor had living room, dining room, kitchen, bathroom and three bedrooms. The forced air outlets for both heat and AC were on the walls near the floor. Since the cool air came out in the lower part of all the rooms, and hot air rises, the higher up you were in a room, the warmer it was. When the cool air reached the level of the thermostat (about 4 1/2 - 5 feet, as I recall), the AC cycled off. Then, when the thermostat sensed warmer, it cycled on. Because the air did not mix sufficiently, the rooms were very warm from the ceiling down 3-4 feet, but cooler below that.

When I set the thermostat to run the fan all the time, the air then mixed sufficiently to keep all the rooms "just right".
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Re: Will adding returns cool the upstairs bedrooms?

Post by LongerPrimer »

I've used window fans set on the floor to even out the temperature in the room. Cold air sinks fast in a room with big temperature differential from ceiling to floor. It is an inexpensive solution that I'd try first. -Why a 8-10" dual window fan, you may ask, they are cheap at HD/Lowes, thermostat controlled, multiple speeds, and returnable if this doesnt work out. :D
Last edited by LongerPrimer on Fri Jun 13, 2014 4:27 pm, edited 1 time in total.
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Re: Will adding returns cool the upstairs bedrooms?

Post by magellan »

Can you get up into your attic easily?

On my system, each of the room vents has an inline damper installed in the duct in the attic. It's something like this one.
http://www.amazon.com/HVAC-Damper-Manua ... ZK9S1ZG79C

They also sell just the damper to go inside an existing duct:
http://www.amazon.com/Speedi-Products-A ... FVV1XCQ371

With these dampers, I can adjust the airflow to each room and get the balance just right. I can attest that they really make a difference.

Perhaps something like this would be a less expensive option.

Jim
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Re: Will adding returns cool the upstairs bedrooms?

Post by YttriumNitrate »

DC is miserable in the summer. Have you considered:

1. Adding doors between the levels to limit hot air rising to the top floor.
2. Adding a widow unit AC to the top level.
3. Giving up on the top level during the summer and just live on the bottom two.
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Re: Will adding returns cool the upstairs bedrooms?

Post by DSInvestor »

dm200 wrote:Where is the return for the upstairs, since you have a separate unit?

What about the upstairs thermostat?

Do you have a setting on the thermostat to have the fan run all the time? If the fan only runs when cooling, and the thermostat senses that it is cool enough, the air conditioning and the fan go off - and it may then warm up in the rooms. If you can, set the fan to run all the time - then the air will be circulated much better.

I once lived (Washington DC area) in a rental house that was a rambler (called a 'ranch' in some areas) with a walk out basement in back. The main floor had living room, dining room, kitchen, bathroom and three bedrooms. The forced air outlets for both heat and AC were on the walls near the floor. Since the cool air came out in the lower part of all the rooms, and hot air rises, the higher up you were in a room, the warmer it was. When the cool air reached the level of the thermostat (about 4 1/2 - 5 feet, as I recall), the AC cycled off. Then, when the thermostat sensed warmer, it cycled on. Because the air did not mix sufficiently, the rooms were very warm from the ceiling down 3-4 feet, but cooler below that.

When I set the thermostat to run the fan all the time, the air then mixed sufficiently to keep all the rooms "just right".
The problem with running the AC fan all the time is that it will put humidity back into the air by blowing over the moist coils while the system isn't cooling. Using fans in the rooms may be a better way to mix up the air.
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Re: Will adding returns cool the upstairs bedrooms?

Post by Easy Rhino »

I don't know DC heat specifically. I remember it being gross the one time I was there in the summer though.

Do you think you'd have windows often at least somewhat often? then a whole house fan might work great. Suck in comfortable air from the outside, equalize the indoor temperature, and as a bonus blast cooler air into the attic, which is probably a brazillion degress. But if it's 95 degrees and sticky outside, then you're not going to want to open up the windows.

Do you have wall insulation right now? Our recently renovated house had ZERO wall insulation. We added some. It was expensive, but it makes a big big difference. If you already have a moderate amount though, I doubt that more would help.

I would view air exchanges as more of a pressure equalization thing. Try closing all the doors while running the AC. If doors are either too hard or too easy to open, then you've got unequal pressure amongst your rooms, and it might take some adjusting by a pro (who's willing to do measurements). We had our dampers on our vents adjusted slightly, but since we usually have doors open we didn't want to add returns.
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Re: Will adding returns cool the upstairs bedrooms?

Post by alec »

I live in the DC area. We got an attic fan and got ceiling fans in the upstairs bedrooms. The ceiling fans made the most difference.
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Re: Will adding returns cool the upstairs bedrooms?

Post by BrandonBogle »

dm200 wrote: I once lived (Washington DC area) in a rental house that was a rambler (called a 'ranch' in some areas) with a walk out basement in back. The main floor had living room, dining room, kitchen, bathroom and three bedrooms. The forced air outlets for both heat and AC were on the walls near the floor. Since the cool air came out in the lower part of all the rooms, and hot air rises, the higher up you were in a room, the warmer it was. When the cool air reached the level of the thermostat (about 4 1/2 - 5 feet, as I recall), the AC cycled off. Then, when the thermostat sensed warmer, it cycled on. Because the air did not mix sufficiently, the rooms were very warm from the ceiling down 3-4 feet, but cooler below that.

When I set the thermostat to run the fan all the time, the air then mixed sufficiently to keep all the rooms "just right".
In my house in NC, the walk out basement does not have vents or a return, but does have the air handler for our single system. There are returns in the living room on the main level and at the top of the stairs on the second level. While the theory was the return at the top of the stairs "caught" the warm air from the main level, the upstairs was very, much warmer than the main level. The thermostat is on the level, so it would turn off before cooling down the upstairs. However, at the time, zero rooms of the house had ceiling fans. After the first year we put in ceiling fans in every room upstairs and it made a HUGE improvement. We just put ceiling fans downstairs while doing other renovations and it has made a huge difference again.

Op, however you decide to do this, it is likely that a good part of this is lack of circulation. If you can get the air circulating better, you will likely have a great improvement. Wish I could provide you more than my non-professional thoughts. Good luck!
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by tibbitts »

In our house we've replaced the windows with low-e (made a dramatic difference in the temperature of the glass, at least), added a half-ton of capacity, a lighter roof with ridge vent and 3 additional vents, insulation in the attic, and... no significant difference. Recently added more duct diameter and a more free-flowing filter (2" pleated vs. 1" non-pleated), but haven't had a chance to determine the effectiveness of that yet.

Ultimately I think the most practical solution to insufficient cooling is more tons of capacity and corresponding ductwork. I think the "danger" of too-many-tons, with 2-stage systems at least, is overrated. If you want the room to be 74 and it's 110 outside you probably just need a lot of capacity to do that. Years ago, we had several companies use calculations to determine the correct size and it was universally agreed to be 3tons. But we've had several years of frequent higher temperatures since, so now we're hearing that everybody is putting 4tons in the same size houses.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by rad597 »

Not an AC expert, but I wonder if the air output is cool, then are the units running long enough to remove the humidity? If the air is cool but the room feels moist and thus uncomfortable/hot, a dehumidifier may help as would a ceiling fan. You could try a small dehumidifier and if that works, consider a whole house one.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by wander »

It could be too hot in the attic. Have you measure the temperature in the attic during the day?
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by JPH »

We have a problem with upstairs versus downstairs temperature differential in our two-story house. We have only one AC unit and do not have air returns in each room. We have only one in the upstairs hallway. We had the area of the single return vent enlarged, but it did not solve the problem.
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Re: Will adding returns cool the upstairs bedrooms?

Post by dm200 »

DSInvestor wrote:
dm200 wrote:Where is the return for the upstairs, since you have a separate unit?

What about the upstairs thermostat?

Do you have a setting on the thermostat to have the fan run all the time? If the fan only runs when cooling, and the thermostat senses that it is cool enough, the air conditioning and the fan go off - and it may then warm up in the rooms. If you can, set the fan to run all the time - then the air will be circulated much better.

I once lived (Washington DC area) in a rental house that was a rambler (called a 'ranch' in some areas) with a walk out basement in back. The main floor had living room, dining room, kitchen, bathroom and three bedrooms. The forced air outlets for both heat and AC were on the walls near the floor. Since the cool air came out in the lower part of all the rooms, and hot air rises, the higher up you were in a room, the warmer it was. When the cool air reached the level of the thermostat (about 4 1/2 - 5 feet, as I recall), the AC cycled off. Then, when the thermostat sensed warmer, it cycled on. Because the air did not mix sufficiently, the rooms were very warm from the ceiling down 3-4 feet, but cooler below that.

When I set the thermostat to run the fan all the time, the air then mixed sufficiently to keep all the rooms "just right".
The problem with running the AC fan all the time is that it will put humidity back into the air by blowing over the moist coils while the system isn't cooling. Using fans in the rooms may be a better way to mix up the air.
The problem in that house was, as best I recall, the ac did not run long enough. Once we had the fan running all the time, it caused the thermostat to kick in the ac a little more. In our case, there was not a humidity problem introduced. Of course, it all depends on the details of the "problem". Trying this is a zero cost "modification" and if it works, the only added cost is the electricity to run the fan a bit more. If it doesn't work, just set the fan back as now - and you are exactly where you were.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by Sidney »

dm200 wrote:The problem in that house was, as best I recall, the ac did not run long enough. Once we had the fan running all the time, it caused the thermostat to kick in the ac a little more. In our case, there was not a humidity problem introduced. Of course, it all depends on the details of the "problem".
This is one of the advantages of a two-stage compressor with VS air handler. The system might be optimal when running longer at lower speeds keeping a uniform temperature.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by BrandonBogle »

Sidney wrote:
dm200 wrote:The problem in that house was, as best I recall, the ac did not run long enough. Once we had the fan running all the time, it caused the thermostat to kick in the ac a little more. In our case, there was not a humidity problem introduced. Of course, it all depends on the details of the "problem".
This is one of the advantages of a two-stage compressor with VS air handler. The system might be optimal when running longer at lower speeds keeping a uniform temperature.
My two-stage heat pump in NC is MUCH more comfortable than the previous houses single-stage unit. And as many of have alluded to, much of this problem could be because of lack of circulation. A two-stage system to promote circulation can go a long way. However, absent changing the air handler (if not already a two-stage one), would be to promote circulation within each room. That has the added bonus of the Op's household feeling more comfortable as the air passing over their skin would add to the "coolness" feeling.
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yolli71
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Re: Will adding returns cool the upstairs bedrooms?

Post by yolli71 »

Thanks for the responses everyone. To answer some of your questions:

1. The energy auditor was BPI certified and a member of RESNET. He did do the blower door test and gave me the before and after results once the work was done.

2. The thermostat is in the master bedroom and there are 2 returns upstairs...one in the master bedroom and one in the hallway.

3. Window units are not allowed per HOA rules.

4. My attic has a ridge vent and a solar powered attic fan. As part of the energy audit service, the guy installed polystyrene baffles as the insulation had been blocking the incoming air.

5. I keep the bedroom doors open so maybe an air return in each room wouldn't have much of an effect?

How do the inline dampers work? Wouldn't that be the same as just closing certain vents? I am intrigued by the inline duct fan...do they provide a big boost of air to the registers? Ceiling fans are probably a good option too.

Grt2bOutdoors brought up a good point where I may need to keep the AC lower throughout the day both upstairs and downstairs. I normally keep the AC on 78 while I'm at work and then lower it to 70 when I get home around 5pm. By the time I put the kids to bed around 8pm, the temperature is around 74. I can't get it down to 70 degrees (what we prefer to sleep in) until after the sun goes down or about 9:30pm.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by jebmke »

I live in MD so have same weather as DC. IMO 70 degrees is pushing an AC pretty hard in this climate. We keep ours at 77 during the day and 75 at night. Ceiling fans make a big difference.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by BrandonBogle »

Yolli, at my house in NC, I do not have that problem and our heat pump can get us to our desired temp quickly, even if they are in the 60s. However, at my mother's house in Miami, we did have that same problem. I installed the same programmable thermostat I have at her house. What I like about this programmable thermostat is rather than say "70 degrees at 5 pm" and the unit kicks into "overgear" at 7 pm, it "learns" how effective the climate control is at your house and when you set it to "70 degrees at 5 pm", it turns however much sooner is needed so it is at 70 degrees BY 5 pm. This may be something worthwhile to let you ease up on the a/c during the day while still "priming" the system to get to your desired temperature when you get home.

However, I would NOT recommend this in ABSENCE of whatever else you decide to do based on this thread. This is just a suggestion to aid comfort in addition to everything else. The thermostat I have, I got from Amazon (they have it at Lowes and Home Depot) here: http://www.amazon.com/gp/product/B0026E ... refresh_T1
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walkabout
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by walkabout »

As others have stated, you are asking a lot of your unit (or any unit for that matter) to bring your upstairs down from 78 to 70 degrees during, arguably, the hottest part of the day (at least when you turn the temp down at 5:00).

The first thing I would try would be to not set the temp so far back during the day and don't set so low after work. Rather than 78 and 70, try something like 75 and 72.

I agree with trying a programmable thermostat (that is made for heat pumps - this is critical to have the setback and recovery function work efficiently during heating season). The thermostat will learn how long it takes to achieve the desired temp from the setback temp and will start cooling early enough to do that.

I also agree with fans, ceiling and/or floor fans for distributing the cool air.

Have you had your unit serviced? Is it possible that it isn't producing enough cold air? Low on freon? Filter or coil dirty? Ductwork sealed and insulated?

If your unit is old (10-15 years or more) and if this is really bothering you, consider getting a new unit. I am a big fan of a two stage heat pump with variable speed air handler. We got a Carrier Infinity last summer and love it. Our system runs on low almost all of the time during hot weather. This keeps the temps even and keeps the humidity low. It will even over cool by two degrees to attempt to achieve the desired humidity. We have it set to 75 most of the time and, with the lower humidity, that is plenty cool (and I don't mind a cool house). At night it drops to 72. We don't use a big setback during the day. With the near constant cooling, you would probably find that your downstairs benefits as well from cool air that flows down the steps.

Some other ideas (not mentioned above and not really considering cost):
1. Do you have good windows? No leaks, insulated glass, low e coating.
2. Solar screens.
3. Awnings.
4. Solar film (be very careful on insulated glass, it might void your warranty - even worse, it might crack the glass).

The above suggestions assume heat gain via windows.
Last edited by walkabout on Sat Jun 14, 2014 4:38 pm, edited 1 time in total.
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HardKnocker
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Re: Will adding returns cool the upstairs bedrooms?

Post by HardKnocker »

yolli71 wrote:
4. My attic has a ridge vent and a solar powered attic fan.
Do you mean a power roof venting fan? That's not right. One or the other but not both. I doubt this is your problem though with your interior cooling.

Wow, 70 degrees is really cranking the A/C. So it gets to 74 upstairs? That's pretty good. I would think with the addition of a room fan you would be quite comfortable (I keep my house at 78).
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yolli71
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by yolli71 »

Hi all...to answer more questions:

1. Yes, I do mean a venting fan (not an actual attic fan). I now realize this maybe wasn't optimal. I used to have an electric powered operated venting fan with no ridge vent...now I have a ridge vent with a solar powered venting fan (they simply replaced the old fan w/ the solar fan). While maybe not optimal, I agree w/ HardKnocker that this probably isn't the problem.

2. I have a programmable thermostat. I got a Nest about two years ago. I set the schedule myself but I'm thinking I need to adjust it.

3. I just had my AC unit serviced about a month or so ago...the guy said both my units were in great shape especially for being 16 years old. Even though it's old, I feel plenty of cold air blowing out of the registers and I'm not ready to replace the whole thing since I know that won't be cheap.

4. My windows are builder grade double paned. Nothing special, but the energy audit guy said they're doing well for the most part...no need to replace them. I also have blackout honeycomb shades for the windows upstairs so I wouldn't think the windows are the problem. Awnings are not allowed per the HOA.

5. Auditor does not recommend whole house fans or attic fans.

6. I have wall insulation. Auditor said trying to add more would be expensive and would not be worth the cost for my problem.

At this point I'm thinking my best options are ceiling fans and possibly the inline duct fans. I know nothing about the inline duct fans though...can someone tell me how this works and if it's really effective?
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by livesoft »

Frankly, I'm surprised the auditor apparently did not recommend ceiling fans.
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yolli71
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by yolli71 »

livesoft wrote:Frankly, I'm surprised the auditor apparently did not recommend ceiling fans.
Good point...I'm kind of surprised too now that I think of it. I'm thinking maybe he didn't mention it b/c he was trying to find the root cause of the problem. Like I said, the thermostat is in the master bedroom which faces the east and has 2 vents and is the coolest room upstairs. When you go to my 2 kids' rooms, they face the west and have one vent each and are noticeably warmer than the master. What irritates me is that it takes an hour or more to cool down the top floor by a degree or two even though the thermostat is in the master bedroom (w/ the 2 vents and the bedroom facing the east).

I'm also concerned b/c we haven't even hit the truly hot days of July/August yet. The auditor told me that returns in each room would definitely help, but he's not sure if it would be obviously noticeable to me (especially 1k noticeable). He recommended that I lower the temp earlier than 5pm so that the unit wouldn't have to work so hard to lower the temp to 70 by the time my kids go to bed at 8pm. I realize that 70 is pretty low, but my wife and I (and our kids who are 2 and 4) sleep better when the temp is low. I'm thinking ceiling fans would help in their rooms even though it doesn't solve the root cause (whatever that may be).

I'm still curious about the inline duct fan, though I need to learn more about it. After discussing this, my wife has at least agreed to go ahead and go w/ the ceiling fans in the bedrooms. My question now is...will installing ceiling fans be a problem when I don't have a ceiling light in any of the rooms? Each room has a light switch and the light switch controls an electrical outlet in the room....there is no ceiling light in the rooms.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by Carl53 »

yolli71 wrote:At this point I'm thinking my best options are ceiling fans and possibly the inline duct fans. I know nothing about the inline duct fans though...can someone tell me how this works and if it's really effective?
I don't think the duct fans are your solution but ceiling fans ought to provide relief. I have had two inline duct fans I installed for a corner bedroom in our ranch style house. Closed bedroom doors aggravated a less than adequate duct system. When the bedroom is in use (ie. a guest is using the room) one may turn the duct fan via a wall switch. This required running new wiring as opposed to having it plugged in and just running it all the time. Leaving it run evens out the room temperature with the rest of the house. It does cause a noticeable background hum as it is in the basement ceiling directly below the room. Two fans because I had to replace the first one after about 10 years of frequent use.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by UpstateNY86 »

Livesoft , there is a reason for that . Care to take a stab? As one whos in the field everyday, the BPI auditing IMO is not the gospel by any means . One thing for sure ceiling fans are a must , and if you can swing it just buy a ductless split system that will easily cool your upstairs . Look into mitsubushi . Most common complaint of every homeowner is the upstairs , so do not beat yourself up over it ....
livesoft
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by livesoft »

If the OP closes the vent in the master bedroom, the cold air will go to the bedrooms on the west side of the house. Air from those bedrooms will travel out of them, down the hall, into the master br and the return vent. The A/C will stay on until the thermostat in the master br says it is cold enough.

The above is an easy experiment to do. My understanding is that the air movement in an A/C system can be "tuned" by inline vents or baffles in the ductwork, but absent those, just use the vents in the room.

True story: I know of a piece of equipment where the installers dropped packing material into the ductwork that blocked the flow. Nobody could figure out why the darn thing never worked right, so they sold it. Upon disassembly for shipping, they found the packing material that was causing the problem.

I suppose airflow through all the upstairs vents was checked though.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by walkabout »

If you are considering duct booster fans, you might think about a register booster fan. It replaces a register cover, thus simplifying installation. Generally, you set it to detect hot or cold air, depending on the season. When it detects air flow it turns on, thus pulling more air into the room. This way it doesn't run all the time. I don't know how effective they are, but they are probably cheaper and easier to install than inline duct boosters. If you tried one or two and liked them, you could then decide if you thought an inline system might be even better. Note that you should also be able to find an inline system with a pressure switch (or direct wiring back to the air handler) so that you don't have to control the fans manually.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by Carl53 »

Carl53 wrote:
yolli71 wrote:At this point I'm thinking my best options are ceiling fans and possibly the inline duct fans. I know nothing about the inline duct fans though...can someone tell me how this works and if it's really effective?
I don't think the duct fans are your solution but ceiling fans ought to provide relief. I have had two inline duct fans I installed for a corner bedroom in our ranch style house. Closed bedroom doors aggravated a less than adequate duct system. When the bedroom is in use (ie. a guest is using the room) one may turn the duct fan via a wall switch. This required running new wiring as opposed to having it plugged in and just running it all the time. Leaving it run evens out the room temperature with the rest of the house. It does cause a noticeable background hum as it is in the basement ceiling directly below the room. Two fans because I had to replace the first one after about 10 years of frequent use.
The reason I do not think duct fans are your solution is that the entire upper floor is hot and is serviced by its own HVAC system. In my case, I have one HVAC system and an area that was underserved.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by Sidney »

UpstateNY86 wrote:Livesoft , there is a reason for that . Care to take a stab? As one whos in the field everyday, the BPI auditing IMO is not the gospel by any means . One thing for sure ceiling fans are a must , and if you can swing it just buy a ductless split system that will easily cool your upstairs . Look into mitsubushi . Most common complaint of every homeowner is the upstairs , so do not beat yourself up over it ....
Mitsu split systems are great but I still wonder if there is something else being missed. He has 3 tons serving 1,300 sf. I would think that would be enough.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by magellan »

A trip into the attic with the unit running to check for leaks in the duct work might make sense. I had a few smallish leaks in my system that were easily found just by passing my hand across the duct work with the unit running. There are some great youtube videos that show how to fix the leaks once you find them. It's really easy.

Be careful not to go up in the attic when it's really hot. The heat can sneak up on you and before you realize you're in trouble, you could pass out. Also, when feeling for leaks, watch out for sharp edges on the sheet metal. I snagged my finger on one particularly rough cut and it made a mess. On the plus side, that was one of the biggest air leaks!
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by catspaw »

I am sure somebody has checked to make sure the wires controlling the AC units are not reversed. As in, the upstairs thermostat controls the downstairs AC. But if not, it is worth turning on one on and making sure the right AC is running.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by yolli71 »

magellan wrote:A trip into the attic with the unit running to check for leaks in the duct work might make sense. I had a few smallish leaks in my system that were easily found just by passing my hand across the duct work with the unit running. There are some great youtube videos that show how to fix the leaks once you find them. It's really easy.

Be careful not to go up in the attic when it's really hot. The heat can sneak up on you and before you realize you're in trouble, you could pass out. Also, when feeling for leaks, watch out for sharp edges on the sheet metal. I snagged my finger on one particularly rough cut and it made a mess. On the plus side, that was one of the biggest air leaks!
I had this work done as part of the energy audit. The auditor used foam and sprayed all over the duct work in the attic.
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by whomever »

Are there doors between the main and upper floors? If not the air can stratify on its own - trying to lower the temp upstairs just results in the cool air flowing down the stairs. Stairways are very large air ducts :-).

We have a 3 story house, and shutting the door at the top of the upper stairs helps equalize the temps between main and upper floors. This is with a single furnace/AC and supply and return ducting on all floors.

If you don't have a door, try hanging a blanket as an impromptu door. My inlaws did that for years (M-I-L actually wove a nice tapestry for the purpose, so it looked nice).
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by yolli71 »

whomever wrote:Are there doors between the main and upper floors? If not the air can stratify on its own - trying to lower the temp upstairs just results in the cool air flowing down the stairs. Stairways are very large air ducts :-).

We have a 3 story house, and shutting the door at the top of the upper stairs helps equalize the temps between main and upper floors. This is with a single furnace/AC and supply and return ducting on all floors.

If you don't have a door, try hanging a blanket as an impromptu door. My inlaws did that for years (M-I-L actually wove a nice tapestry for the purpose, so it looked nice).
No, and unfortunately there's no way to do this. Our house was built in '98 and has an open floor plan with vaulted ceilings.

Just today, the high temp was around 90 degrees. I had all the shades closed all day and had the AC running at 75 while I was at work. I lowered the temp upstairs to 70 at 6pm and it's now 8pm and it has dropped 1 degree to 74....2 hours to drop 1 degree. This is the case even though I have two 3 ton units for the house that are supposedly in great shape with blackout shades upstairs and the air seal job I had done in the attic. This just doesn't seem right to me.

I wonder if it's possible that the ductwork in the attic gets warmed up enough in the hot attic to produce air that isn't as cold as it should be?
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by DSInvestor »

yolli71 wrote:I wonder if it's possible that the ductwork in the attic gets warmed up enough in the hot attic to produce air that isn't as cold as it should be?
What's the temperature of the air coming out the AC vents compared to the temperature at the return air? I believe the vents should be 15-20F cooler than the return air (air intake).
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Re: Will adding [air duct] returns cool the upstairs bedroom

Post by yolli71 »

DSInvestor wrote:
yolli71 wrote:I wonder if it's possible that the ductwork in the attic gets warmed up enough in the hot attic to produce air that isn't as cold as it should be?
What's the temperature of the air coming out the AC vents compared to the temperature at the return air? I believe the vents should be 15-20F cooler than the return air (air intake).
Good question...I have no idea. Is there any special type of thermometer I should use for this?
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