Possible attic damper?
#1
Member
Thread Starter
Possible attic damper?
I have hot air heat in Connecticut and recently completed an extensive attic project to seal and insulate the attic above my second floor. Good news: the attic is much cooler and the second floor is much warmer. Bad news: second floor rooms are at least 8 degrees warmer than the main floor (74 versus 66 degrees) and very uncomfortable.
I'm seeking to adjust the second floor dampers but can't find them. Would there normally be a damper to adjust the second floor from the basement or would everything be in the attic? (With all the insulation I've added I'm hoping I don't have to search the attic.)
Also, I've been told here not to close the second floor registers and know that was good advice. Could closing the second floor damper also harm my system?
I'm seeking to adjust the second floor dampers but can't find them. Would there normally be a damper to adjust the second floor from the basement or would everything be in the attic? (With all the insulation I've added I'm hoping I don't have to search the attic.)
Also, I've been told here not to close the second floor registers and know that was good advice. Could closing the second floor damper also harm my system?
#2
Member
Closing a damper or closing a register would be essentially the same. Dampers are generally adjusted when the system is first balanced and then left that way, but not all supply lines will have a damper.
Closing too many registers reduces the air flow over the heat exchanger which can result in it overheating. The symptom that would indicate you have reduced the air flow too much would be the burner cycling on and off while the fan runs continuously all during a normal call for heat.
But the rooms being significantly warmer upstairs than downstairs is indeed a comfort issue. For the short term, where are the return registers both up and downstairs?
When the heat loss of a house is reduced, the resulting run times for the furnace become shorter providing less air circulation. That can result is the natural distribution of the warm air being pushed to the upper floors. You could run your furnace fan continuously for a day to see if the temps even out. If your warm temps up there are due to natural layering then closing off supply registers will have little effect.
Bud
Closing too many registers reduces the air flow over the heat exchanger which can result in it overheating. The symptom that would indicate you have reduced the air flow too much would be the burner cycling on and off while the fan runs continuously all during a normal call for heat.
But the rooms being significantly warmer upstairs than downstairs is indeed a comfort issue. For the short term, where are the return registers both up and downstairs?
When the heat loss of a house is reduced, the resulting run times for the furnace become shorter providing less air circulation. That can result is the natural distribution of the warm air being pushed to the upper floors. You could run your furnace fan continuously for a day to see if the temps even out. If your warm temps up there are due to natural layering then closing off supply registers will have little effect.
Bud
#3
Member
Thread Starter
Bud, thanks for responding and for your help in the past. I follow what you're saying about balancing but I'm hoping I can do something. I'm very frustrated that my extensive sealing and insulating has changed the dynamics of my home and I seem to have exchanged one problem for another.
In answer to your question, we have 11 registers plus 4 return registers on the first floor and 8 registers plus 2 return upstairs.
I'm seriously considering getting an energy efficient fan for the top of the stairs to blow the air back down.
In answer to your question, we have 11 registers plus 4 return registers on the first floor and 8 registers plus 2 return upstairs.
I'm seriously considering getting an energy efficient fan for the top of the stairs to blow the air back down.
#4
Member
It sounds like you have plenty of supply and return registers. By testing with your furnace fan you will confirm a circulation issue.
We have a saying in the energy auditing business "the house is a system". And what you are experiencing is exactly one of the unintended consequences. But it isn't bad news, just an indication that the rest of the system needs to be brought into line, heat loss downstairs and air circulation.
Measure the temperature being delivered throughout the house at each supply after they have come up to full temp.
Do you have access to many of the ducts in the basement?
Bud
We have a saying in the energy auditing business "the house is a system". And what you are experiencing is exactly one of the unintended consequences. But it isn't bad news, just an indication that the rest of the system needs to be brought into line, heat loss downstairs and air circulation.
Measure the temperature being delivered throughout the house at each supply after they have come up to full temp.
Do you have access to many of the ducts in the basement?
Bud
#5
Member
Thread Starter
Bud, I'll measure the temperature at the registers tomorrow and post the result. Yes, I have access to all the basement ductwork. I've done some work down there, but nothing like the attic.
What are you thinking bout as you say the system needs to be brought into line?
What are you thinking bout as you say the system needs to be brought into line?
#6
Member
I suspect the furnace is oversized, they usually are even before improvements are added, but after, more so. What that does is give you short bursts of heat to satisfy the thermostat, but not long slow runs that a smaller furnace would require. Air conditioning also suffers from oversizing as the air needs the long run times to remove the humidity.
Where you currently sit could be determined by a heat loss calculation. Many helpers here for a DIY on that, many better than myself as the manual J is outside my permitted scope here in Maine. But that number will explain sizing and at some point it may become economically justifiable to replace the furnace. Hope it isn't already a new one.
You mentioned a fan from upstairs to blow the heat down. Since I'm not a HVAC pro I can think about non-standard options. If a small continuous run fan were added to the upstairs return path blowing towards the furnace, that air would blow out the downstairs return and through the furnace and out all of the supply registers. Now, I don't know what your ducts look like, but a bypass configuration of some sort might even out the temperatures. Continuously running circulation fans are becoming more common with tight energy efficient homes.
Bud
Where you currently sit could be determined by a heat loss calculation. Many helpers here for a DIY on that, many better than myself as the manual J is outside my permitted scope here in Maine. But that number will explain sizing and at some point it may become economically justifiable to replace the furnace. Hope it isn't already a new one.
You mentioned a fan from upstairs to blow the heat down. Since I'm not a HVAC pro I can think about non-standard options. If a small continuous run fan were added to the upstairs return path blowing towards the furnace, that air would blow out the downstairs return and through the furnace and out all of the supply registers. Now, I don't know what your ducts look like, but a bypass configuration of some sort might even out the temperatures. Continuously running circulation fans are becoming more common with tight energy efficient homes.
Bud
#7
Member
Thread Starter
Bud, thanks for all the information and assistance. I've looked over the Manual J calculation (but didn't actually do it) and I understand the situation. The home was built in 1987 and still has the original oil burner. Energy efficient windows have been installed, ductwork was insulated, and I upgraded the attic to R-60 in Connecticut so I now have a unit that creates over-abundant heat.
I've been reading about fan options and I'm not terribly excited about circulation fans or bypass configurations. I'm going to just buy a small fan to blow some air downstairs and leave it at that for now. Anyway, winter should be over by Memorial Day and I'll be fine then.
I've been reading about fan options and I'm not terribly excited about circulation fans or bypass configurations. I'm going to just buy a small fan to blow some air downstairs and leave it at that for now. Anyway, winter should be over by Memorial Day and I'll be fine then.
#8
Member
Memorial day may be optimistic, it is currently 8 degrees here.
In addition to checking the supply temps, clock your on/off cycle time for your furnace and note the outside temp.
With an 1987 oil burner there will probably be some reasonably priced more efficient systems to consider. Heat pumps have made impressive gains and once the heat load is scaled way back, the high electric costs are not that big of a factor. Plus, roof top solar can be brought into play.
Curious, have you seen a measurable decrease in those oil bills? My deep energy retrofit is finally showing gains in bot comfort and fuel consumption. Once completed over this summer I'm expecting impressive results.
As a note, newer technology is now making efficient long lasting fans available for many applications. A 100 cfm fan configured to circulate air through your current ducts would probably circulate the entire house volume in 3 hours, 6,000 cubic feet per hour for a 16,000 cubic ft house. That fan, run 24/7 might only cost 20 or 30 dollars per year, I'd have to check. Plus, you might not need it all 12 months.
Best
Bud
In addition to checking the supply temps, clock your on/off cycle time for your furnace and note the outside temp.
With an 1987 oil burner there will probably be some reasonably priced more efficient systems to consider. Heat pumps have made impressive gains and once the heat load is scaled way back, the high electric costs are not that big of a factor. Plus, roof top solar can be brought into play.
Curious, have you seen a measurable decrease in those oil bills? My deep energy retrofit is finally showing gains in bot comfort and fuel consumption. Once completed over this summer I'm expecting impressive results.
As a note, newer technology is now making efficient long lasting fans available for many applications. A 100 cfm fan configured to circulate air through your current ducts would probably circulate the entire house volume in 3 hours, 6,000 cubic feet per hour for a 16,000 cubic ft house. That fan, run 24/7 might only cost 20 or 30 dollars per year, I'd have to check. Plus, you might not need it all 12 months.
Best
Bud