user1234

I have two very cold rooms in my house. This winter I purchased register blowers and they brought the temperature in the rooms up to the same as the rest of the house. Does this mean that the problem is related to HVAC? The ducts in the open basement had lots of gaps which we sealed up, so it wouldn't surprise us if the rest of the ductwork was done just as slopily. I'm just not sure if it would be bad enough to create a 4-6'C difference in these rooms. I would love if the register blowers were an easy solution - however they are very noisy.
Is there anything I can try without opening the ceiling below the rooms to inspect the ductwork? If the only solution is to take the ceiling down, are there any quiet register blowers out there for at least a temporary fix?

CharlieO

But the sounds of it, the real issue is not with with the HVAC unit if you can raise the temperature that quickly with just register Blowers, the system seems to be working it's just either the air is not getting to those rooms be sound like those rooms of the furthest from the units, seems like they're upstairs rooms when you talk about tearing theceiling down. You may have leaks in the ductwork, you may have issues with insulation in the rooms and the attic, around Windows, storm windows.
Without supplying a whole lot more information it's hard to say exactly what they would be.
As far as quieter register boosters, don't know what kind you bought, Do some research of different manufacturers and see if they give you a noise rating.

joecaption

Way to many things that can cause some rooms to be colder then another and it would take a real pro to figure out why.
Some simple things are the systems unblanced. It's as simple as closing some of the other registers to increase the air flow to the cold room.
Uninsulated duct, leaking ducts, no return air vent, or in the wrong place.
No 1" gap under the rooms doors. ECT.

user1234

YOu are right that these rooms are the furthest from the furnace.
We started off not looking at the HVAC. We have a cantilever so we opened it up and reinsulated it really well. No difference to the room temperature. We had decent attic insulation, but added more and made sure the soffits weren't covered. No difference in the room temperature. When we blocked off a couple of registers it did bring the temperature up a little bit, but still not to a comfortable level. We checked for air leaks around the windows and they are okay as well. We have return air ducts leaving both rooms, so the air isn't getting stuck in the room.
I wasn't really able to find any information indicating any external register boosters are quiet - just inline ones that would require opening the ceiling below and putting in access panels so the fans could be cleaned.

We have been told that the furnace is a bit big for our home size which would have the furnace turn on and off quickly - maybe this would prevent the warm air from reaching the furthest points to provide enough warm air before it shuts off?

user1234

We played around with closing some ducts and were able to bring the room up a degree or two but it wasn't enough of a difference.
There is a return air vent in both rooms on the other side of the room at the floor level. There is a gap under the doors - haven't measured, but seems adequate.

Likely the answer is to open up the ceiling below the rooms - but would prefer not to do that if that isn't the real answer and it isn't something we can do in the next little while. If this is the only thing left to look at, we are hoping to find a temporary solution.

nealtw

Try closing cold air returns in the warmist part of the house.