Air circulation issues

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psteinx
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Air circulation issues

Post by psteinx » Thu May 18, 2017 6:04 pm

A good older thread here:
viewtopic.php?t=141094

But I want to start a new thread with some of the issues we're facing (some similarities to the OP in the other thread, but some differences, too)

Our situation:

2 story house (about 2530 s.f. on 2 main stories), with mostly finished basement, so effectively 3 levels. All within the same cooling envelope. Midwest - hot summers, cold winters.

Single zoned HVAC. Furnace/air handler in the basement, A/C condenser outside.

As you might imagine, it is difficult to keep the upstairs comfortable.

In addition, there are only 2 air returns on the top floor - one in the hallway (which is wide open to, and overlooks, a 2 story entrance foyer/atrium), one in the master bedroom.

At night, folks like to keep the bedroom doors shut, for general privacy, noise, light, etc. People go to bed at different times. But only the master BR has an air return. Furthermore, in two of the bedrooms, the lone air vent is partially obstructed by a bed, and it is not easy to arrange the furniture so as to avoid this.

Master BR has a ceiling fan, used often but not always at night. Other BRs do not have a ceiling fan.

Some possibilities:
1) Add air returns: From other thread(s) on BH, it seems at least some folks have done this, but I would think it might be difficult in a house already built, with a finished basement. Not sure how much good it would do.

2) Add ceiling fans to BRs. But if the door is shut, this would mostly push the air around within a small, semi-sealed BR.

3) Zone/supplement entire HVAC system - either with a full new unit, or mini-splits. But this seems like an expensive, somewhat over-the-top solution.

4) Add simple vents from BRs to hallway (that in turn opens pretty broadly to the main part of the house). Simple solution, but might be aesthetically unattractive, and would potentially be a conduit for noise.

5) Some sort of powered venting/air movement system that focuses on moving air among the bedrooms/hallway. i.e. Rather than trying to push more air up from the basement air handlers, just focus on better circulation among the air that is already near the top of the house envelope. Or perhaps something that can add circulation between basement and upstairs.

6) Ceiling fans for the hallway/atrium. We could add fans in the main upstairs hallway or the 2 story atrium that that hallway overlooks. This wouldn't directly address BR circulation issues, but might be an aesthetically pleasing way of increasing general circulation, that then might complement other methods focusing on the BRs...

7) ??? Something I haven't heard of/thought of...

Thoughts?
Last edited by psteinx on Thu May 18, 2017 8:53 pm, edited 1 time in total.

Easy Rhino
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Re: Air circulation issues

Post by Easy Rhino » Thu May 18, 2017 6:36 pm

psteinx wrote:4) Add simple vents from BRs to hallway (that in turn opens pretty broadly to the main part of the house). Simple solution, but might be aesthetically unattractive, and would potentially be a conduit for noise.


having vents added to the bottom of the doors, or just having the bottom shaved so there's a larger gap between door and floor would accomplish this. This is if the problem is temperature differentials because air is getting 'trapped' in the bedrooms.

if the bedroom residents just want air blowing around, then they'll want it blowing around no matter what... then put fans of some sort in them.

Dakotah
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Re: Air circulation issues

Post by Dakotah » Thu May 18, 2017 8:36 pm

If temperature is the primary concern upstairs...I would recommend researching the Ecobee thermostats. You can then use the remote sensors to accurately control the temperatures upstairs during the night while people are sleeping. That is what I have done in our house. I have a remote sensor in each bedroom upstairs. During the night, the downstairs sensors are disregarded...and the sensors upstairs are averaged to control the thermostat. It causes our downstairs to get quite cold at night, which increases energy usage in the summer...but it has done wonders for our sleeping comfort.

It might not solve your particular problem alone, but I think it would be a step in the right direction.

frugalecon
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Re: Air circulation issues

Post by frugalecon » Thu May 18, 2017 8:47 pm

Wow, I have had very similar issues. One bedroom on the second floor has a return and a very robust supply (it is a straight shot up from the furnace room in the basement), while two bedrooms have no return and weak supply, this floor is only 630 square feet, so a separate forced air HVAC unit seems like overkill, I have considered a ductless mini split heat pump system, but the wall units are a bit unsightly. Have you considered that route?

I live in a neighborhood that would support a much bigger house, so I could imagine remodeling to a bigger space with a zoned unit, but it is more than we need. Almost surely what the next owners will do, though.

takeshi
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Re: Air circulation issues

Post by takeshi » Fri May 19, 2017 8:05 am

Sounds like you need HVAC specialists (get more than one and compare findings) to truly determine the cause(s) of your issues and to recommend suitable solutions. I'd be leery of relying on discussion forum diagnosis for something like this. Problems can seem to be similar with 2 different cases yet have entirely different causes and solutions.

fposte
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Re: Air circulation issues

Post by fposte » Fri May 19, 2017 8:10 am

It's also worth looking at non-HVAC mitigations--have you had your insulation checked or beefed up (and not just the under-roof insulation)? What kind of blinds do you have in those rooms? Triple-cell honeycombs that I keep down during the day helped hugely in my second story, and I got a boost from the insulation as well. Those helped.

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Ged
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Re: Air circulation issues

Post by Ged » Fri May 19, 2017 8:30 am

I have a similar issue in my home. My upstairs has a large central return in the hallway and no returns in the bedrooms.

Replacement windows and insulating blinds made a difference, but not enough.

Experimentation with leaving the doors slightly open plus having the HVAC fan run continuously in summer makes a significant difference.

I haven't gotten around to vented doors but it's on my list.

I'm also considering a ceiling fan in the central stairwell to try to mix the downstairs and upstairs air.
Last edited by Ged on Fri May 19, 2017 8:35 am, edited 1 time in total.

Globalviewer58
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Re: Air circulation issues

Post by Globalviewer58 » Fri May 19, 2017 8:31 am

Air circulation issue may be addressed by installing a vent above the door or in the wall of the bedrooms that do not have an air return. The vent allows air to exit the bedroom. I did this in our master BR which had no air return. The results improved the air flow to our satisfaction. It is as simple as measuring to an area in the wall that is large enough to fit the vent and is between wall studs. Cut the sheet rock on each side of the wall, insert the vent and screw in to the sheet rock.

You could try this in one room and judge the results for yourself.

Here's a link to a vent that includes a noise baffle to reduce sound transmission through the vent. http://www.homedepot.com/p/Battic-Door- ... lsrc=aw.ds

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dm200
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Re: Air circulation issues

Post by dm200 » Fri May 19, 2017 9:04 am

Years ago, I lived in a rental single family home (rambler) that did not keep cool enough (air conditoning) on the hot days. The ac would cycle off as the thermostat thought it was cool enough. We solved the problem by setting the ac to have the fan run all the time, and not just go off when it thought it was cool enough. The fan running all the time caused the air to circulate and mix much better.

Griffeycom
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Re: Air circulation issues

Post by Griffeycom » Fri May 19, 2017 9:06 am

OP has described my house to a T. Even SqFt is almost identical. One thing I have considered that you haven't mentioned is additional insulation and ventilation in the attic. We have only been through half a summer in this house but it's heating up again here and it's getting hot. I need to call some people to see if we have enough ventilation / insulation.

I found found that for now the best thing we can do is run the house fan all day and ceiling fan when we are in the room.

mw1739
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Re: Air circulation issues

Post by mw1739 » Fri May 19, 2017 9:09 am

I did option #3 - it was expensive, but has resulted in the best comfort.

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jeffyscott
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Re: Air circulation issues

Post by jeffyscott » Fri May 19, 2017 1:21 pm

Ged wrote:Experimentation with leaving the doors slightly open plus having the HVAC fan run continuously in summer makes a significant difference.


When you need a new HVAC system if you get one with a variable speed ECM blower, you can have the fan run continuously at low speed during all seasons. This supposedly costs only $60-100 per year in electricity.

We have a ranch and unfinished basement, so don't have the problems that multi-story houses do, but running the fan all the time does help balance things. It also helps distribute humidity from bathrooms and results in very little dust settling.
press on, regardless - John C. Bogle

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