Colder Upstairs

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Old 11-16-09, 08:10 PM
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Colder Upstairs

The thermostat for my forced hot air system is on 1st floor and I am so confused why it is one to two degrees cooler on the 2nd floor. If heat rises then shouldnt the 2nd floor be warmer. The insulation in the attic above my 2nd floor was installed two years ago. All recessed lighting on the 2nd floor were replaced with air-tite cans. I weatherstripped all the windows as well for a tighter fit. There are 3 bedrooms on the 2nd floor with one register in each room.

I have a return on the ceiling at the top of the stairs of the 2nd floor that I cover with those magnetic covers so the hot air does not get sucked back in. Can someone please advise what is wrong or what I can do to correct this?
 
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Old 11-16-09, 08:53 PM
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How big of a return are we covering up here?

Have you had an Energy Audit done on your home? Maybe walls are lacking of insulation there....

How's the air temp coming out of the vents upstairs?

Does the furnace run long cycles or is it short?
 
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Old 11-16-09, 09:11 PM
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The return grille that I cover on the ceiling at the top on the 2nd floor is 10" x 10". I forgot to mention I have an 8" x 8" return grille on the high side of our master BR wall on the 2nd floor that I keep open.

I had an insulation company come in with that infra-red laser and said that I had enough insulation in the walls of the 2nd floor.

I dont know what the air temp is coming on the 2nd floor registers.

It runs short cycles. It does not take long to adjust the temps. I also closed the vents near the 1st floor thermostat.

I do have the ability to move the thermostat to the 2nd floor if I wish by activating the indoor sensor I installed on the 2nd floor which works great during the summer to cool the 2nd floor. I tried using that with the heater during these colder temps but it really did not make a difference.
 
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Old 11-16-09, 09:14 PM
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Hi Mikey, do you have another return for the furnace somewhere? Ditto on what Jay asked. Also, remember, the ceiling for the second floor faces the cold attic, where the ceiling for the first floor faces a warm second floor. So, if we apply some heat loss logic; You are delivering heat to the upstairs areas and to the downstairs areas. Plus some of the downstairs heat is naturally going up. All said and the temp upstairs is colder than down. Therefore you heat loss upstairs is more than down.

The energy audit Jay mentioned would be very revealing. First, what style is your home, cape, full two story, or other. Any sloping ceilings? Are any rooms over unheated spaces, like a garage or overhang? You mentioned ceiling insulation, but didn't say what type or how much. Wall thickness/insulation, age of house, type of windows, and any other details you can add.

Bud
 
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Old 11-16-09, 09:40 PM
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My NJ house is a colonial-split level home. I have two returns on the 1st floor: one low underneath stairwell and one 8x8 on the ceiling in the split level side. I mentioned the two returns and locations on the 2nd floor. All my windows are double-pane. The master BR is a cathedral room with no attic above. The attic insulation that was installed is R-38 which covers the other 2 BRs, bath and mini-hallway.

Are you saying that because my 2nd floor ceiling faces a cold attic is why my 2nd floor is colder than my 1st? Isnt that the purpose of attic insulation?

Should I take the cover off the one return grille on the 2nd floor? I just dont want the hot air that rises to the 2nd floor to be sucked back into the system via that return grille which is why I covered it.
 
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Old 11-16-09, 09:45 PM
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I forgot to say this in my earlier post... If the temps are only 1 to 2˚ cooler upstairs, I wouldn't even worry about it... My house is -/+ 1˚ from one another, and I feel that's good!

If the bedrooms was 10˚, then I'd be looking around to see why it's that cool up there.
 
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Old 11-17-09, 05:02 AM
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Closing off supply or return duct is not a good practice. If it repeats the short cycles several times before it reaches the set temperature, then it is likely overheating due to a lack of air flow. Better to leave all grills uncovered. If the stat is near a supply, the stat should be moved or the supply at least diverted away from blowing near the stat. Yhat can cause short cycling also.

Are you saying that because my 2nd floor ceiling faces a cold attic is why my 2nd floor is colder than my 1st? Isnt that the purpose of attic insulation?
Yes, insulation in the attic reduces the heat loss, but does not eliminate is. Plus the cathedral ceiling probably doesn't have the same R=38.

If your walls are 2x4, then you may have all the insulation that will fit already in there, but that is not enough. If 2x6, then better, but at the bare minimum.

Knowing how old your house is helps us judge how it was built. Example, recent construction might wave sealed air ducts, but anything 10 or more years old would typically not. If the ducts in the basement are just metal tubes stuck together with no sealant or foil tape around EVERY seal, then the system is loosing air to places it should not and pulling air into the house from outside. Air sealing a forced hot air system is important. Plus, the return air paths are often just stud bays, again typically poorly sealed and drawing in cold air.

Now, estimate where all of your supply ducts run and you will find they are longer runs to the upstairs and often not fully insulated. That means the air that finally gets to the upstairs has already lost some of it's heat and is cooler at the register. That's why Jay asked for temps at the registers.

It sounds like you have a very nice home, but as Jay suggested, an energy audit would be a good idea. Do it yourself, of bring someone in, but it will definitely reduce your heating costs and help resolve your temperature concerns.

Bud
 
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Old 11-17-09, 09:32 PM
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My stat on the 1st floor and indoor sensor on the 2nd floor are not near supplies. They are near return grilles. Is it better to have the system use the 1st floor stat or 2nd floor sensor for temp reading?

Should I remove the vent covers off the 2nd floor return grille even though I have 3 more returns throughout the house?

Is it necessary to add more insulation in the attic?

Definitely, the cathedral does not have R-38. Is there anything that I can do in the cathedral room?

The 2nd floor of our 1960s home was an addition made about 6 years ago so insulation on the 2nd floor walls should still be fairly new.

The previous owner replaced the entire furnace 5 years ago and put new flex ducts throughout the basement. However, they kept the original pipes in the walls that lead to the supply vents in each room.

I probably agree about the loss of heat by the time it reaches the 2nd floor. Is there anything that can still be done about that without making a big mess and investment?

Lastly, how much are energy audits and where do I go to get one?
 
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Old 11-18-09, 05:43 AM
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Originally Posted by MikeyBoy View Post
Is it better to have the system use the 1st floor stat or 2nd floor sensor for temp reading? Just a different reference point, but optional

Should I remove the vent covers off the 2nd floor return grille even though I have 3 more returns throughout the house? If they are high/low vents in the same stud bay, then it probably doesn't matter. If they are seperate return paths to the furnace, I would uncover it as the total return capacity should be larger than the supply.

Is it necessary to add more insulation in the attic? With r=38 now, not a big difference, although the final number should be closer to 50.

Definitely, the cathedral does not have R-38. Is there anything that I can do in the cathedral room? Not easily, adding several inches of rigid to the inside over the current sheetrock or after removing the existing sheetrock and then installing new drywall works, but is a project.

The 2nd floor of our 1960s home was an addition made about 6 years ago so insulation on the 2nd floor walls should still be fairly new.
But the transition might not have been the best as far as air leakage. The energy audit with a blower door and IR camera could tell.

The previous owner replaced the entire furnace 5 years ago and put new flex ducts throughout the basement. However, they kept the original pipes in the walls that lead to the supply vents in each room. Flex ducts are a quick fix, not the best. The audit can test the ducts for leakage. Ask for a duct blaster test.

I probably agree about the loss of heat by the time it reaches the 2nd floor. Is there anything that can still be done about that without making a big mess and investment? A booster fan to increase the air flow to the 2nd floor can increase the energy going up. Also, if the supplies are inside a room and the returns are outside, how does the air get from supply to return. Under the door? If the carpet is sealing the bottom of the door, then you are blocking the supply air and reducing the heat flow to that room.

Lastly, how much are energy audits and where do I go to get one?
Here is one list. RESNET - Member Directory You will have to search it for NJ. Google energy auditors your area or check with town office or real estate folks. Glad to comment if you talk to one and not sure what he/she is offering. $300 to $400 for a full audit would be ok.

Bud
 
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Old 11-18-09, 03:39 PM
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2nd floor supplies are in rooms while one return is in the hallway and the other is in our cathedral master BR.

2nd floor is all hardwood floors with the doors open. We dont have kids yet so the other 2 BR doors are left open. If the doors are closed, I would assume under the door. Is there a better solution?
 
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Old 11-18-09, 04:16 PM
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It takes almost a 2" undercut on a door to provide sufficient area to avoid pressurizing a room. We are talking very low pressures, but enough to force warm moist air out through exterior walls where it can deposit moisture as it cools.

To get a better picture of where your heat is going so you can determine the best approach to reducing the loss, you are going to have to DIY some heat loss calculations or have someone do it for you, ie an energy audit.

Don't feel bad, your house is built just like several million others out there and they all thought it was the right way to do things back then. Over the course of the next 20 to 50 years, we are going to have to rebuild most of the home in America. We just won't be able to waste the energy like we have been.

I like the one comments on one of the the internet news links, "while visiting China, Obama will visit some historical site, the great wall, and of course, America's cash".

Bud
 
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Old 11-18-09, 06:14 PM
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I put in a 30" return grill in the wall to the outside hall where the main return is. The one in the BR is near the floor, the one in the hallway is near the ceiling. This keeps the noise down by providing a baffle, but allows decent airflow. The door undercut also helps, mine are about 1" to 1 1/4". In the other two large bedrooms, I have a separate return going directly to the return duct. Those, along with the door undercut, seems to be sufficient. I used to be able to feel the door resisting when I opened it with the heat running, I don't notice that anymore.
 
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