[bobgodd]

Hello. I have one room, my master bedroom, that is ridiculously cold compared to the rest of the house. My wife and I just purchased the home (first home) two months ago, and the weather was still warm in Southern California at the time. While it doesn't get too cold here, there were a couple occasions where we did not leave the heater on at night and our bedroom was on the 40s!!

So in my quest to figure out why my bedroom was so cold, we've stumbled across a few issues that will need addressing. There is no window, only one sliding patio door that had a huge crack in it. I sealed it up with caulking as a temp fix but we're replacing that door shortly. Another thing I stumbled across was that my forced air heating system might not be as efficient as possible. If it comes down to an issue of a little bit of ducting work and some elbow grease, I have no issue going a little extra mile to make it as efficient as possible.

The furnace is in a cabinet in the hallway, and there is only one cold air return and it is directly below the furnace cabinet in the hallway. I've read that my bedrooms might not be cooling properly because we leave the doors closed at night time and there is no cold air return inside the room, which causes the heat register to not be able to force air properly. Some solutions to this that I've found in my [brief] research were to place cold air returns in each room, or to install transfer ducts/grills in the attic - since that's where my current ducting is.

So my question is, within the scope of obvious/non obvious limitations, which would help make my system as efficient as possible? All of the heat registers are in the ceiling, and within a few feet of the openings of all the rooms. If I were to install cold air returns, they would have to be in the ceiling as well; is that going to help, or is that counter-intuitive? Please advise!

Rob

 

[beenthere]

If you move the supplies toward the outside walls and hen use the existing hole for your transfer grille, you should get the result you want.

 

[joecaption]

Those ducts where suppost to be "washing" air across all the windows. Right now the cold air coming in the windows is just droping to the floor and cooling the whole room.
Is there a about a 1" gap under the doors? It's needed so the air can be sucked out of the room at the floor level and into the cold air return.
Is that garage wall insulated and sheetrocked with 5/8 sheetrock?

 

[bobinphx]

I had similar issues a couple of years ago! I put in transfer ducts, solved the issue. Additionally, while researching hvac I also found lots of other issues. My systems static pressure was way high (1.5 Iwc). I found that replacing the plenum box, removing almost all flex, adding a second return grill and doubling the return duct and finally using 4 inch merv 11 media filters fixed the problems!!!!!!! So I just wanted to say, it is possible to fix your issues. Comfort was the biggest benefit, but a 25 percent decrease in my electric bill was great too!!!!

 

[Fix'n it]

is the room ok when the door is left open ?

 

[bobgodd]

Thanks for the replies everyone!

If you move the supplies toward the outside walls and hen use the existing hole for your transfer grille, you should get the result you want.

Are you saying that I would use the existing location (after relocating the supply) as a transfer grill, or as a cold air return? My understanding of the differences between the two is a bit limited.

Those ducts where suppost to be "washing" air across all the windows. Right now the cold air coming in the windows is just droping to the floor and cooling the whole room.
Is there a about a 1" gap under the doors? It's needed so the air can be sucked out of the room at the floor level and into the cold air return.
Is that garage wall insulated and sheetrocked with 5/8 sheetrock?

There is about a 1" gap under all of the doors; that's actually part of what started this initial search. I was standing in front of my bedroom door and felt a ton of cold air rushing over my feet from under the closed door. I've read that even that gap, isn't good enough for a proper return when the door is closed?

The garage is not insulated, on any walls, but the kitchen doesn't seem to have problems getting too cold. The problem is really evident in the master bedroom and the other spare room that sits in the corner of the house.

I had similar issues a couple of years ago! I put in transfer ducts, solved the issue. Additionally, while researching hvac I also found lots of other issues. My systems static pressure was way high (1.5 Iwc). I found that replacing the plenum box, removing almost all flex, adding a second return grill and doubling the return duct and finally using 4 inch merv 11 media filters fixed the problems!!!!!!! So I just wanted to say, it is possible to fix your issues. Comfort was the biggest benefit, but a 25 percent decrease in my electric bill was great too!!!!

If I do end up putting returns in each room, will they need to add up to a total area of the current return? It's fairly large, at least I think it is; the return grill is 14x25.5 inches.

is the room ok when the door is left open ?

The room seems to heat better with the door open, but it's still colder than any other room in the house. Definitely think that part of the problem is the old inefficient aluminum sliding door.

 

[bobgodd]

This is the current return:


This is the crack in the bedroom slider:

There was another crack on the outside that I sealed with caulk and I'm going to seal this one right now.

 

[beenthere]

[QUOTEAre you saying that I would use the existing location (after relocating the supply) as a transfer grill, or as a cold air return? My understanding of the differences between the two is a bit limited.][/QUOTE]

They can be used for either. Returns work better then transfer.

Your master bedroom needs an additional supply.

 

[bobgodd]

Are you saying that I would use the existing location (after relocating the supply) as a transfer grill, or as a cold air return? My understanding of the differences between the two is a bit limited.]

They can be used for either. Returns work better then transfer.

Your master bedroom needs an additional supply.

It's not an overly large bedroom. The whole house is only 1460 sq ft.

 

[beenthere]

It's not an overly large bedroom. The whole house is only 1460 sq ft.

Its not the size. That sliding door will have more heat loss then any of the other outside walls of the other bedrooms do.

 

[bobgodd]

Its not the size. That sliding door will have more heat loss then any of the other outside walls of the other bedrooms do.

Would that still be an issue if we're having the door replaced? The door will be replaced with a more efficient vinyl slider very soon.

 

[beenthere]

Would that still be an issue if we're having the door replaced? The door will be replaced with a more efficient vinyl slider very soon.

Yep, glass still transfers a lot of heat.

 

[carmon]

generally if you just push the air in with no return you wont be comfortable... the air needs to be pulled back as well....

 

[Fix'n it]

i would replace the doors first. that may be all/most of your problem. and your doing it anyway. after that, i would trim the bottom of the doors.
then go from there.

 

[Focused2]

Filter new?

You did not mention inspecting the condition of the air filter. Make sure that is fine, affects amount of air going through ductwork. You did not mention the location of the t-stat (thermostat). Normally near that return air grill in hallway. If you have ceiling fans see if they have a reverse, blows air into ceiling and brings down the hotter air near ceiling to the living area. Set it to low! Does not take much air to move warm air. Good luck with it, Joe

 

[bobinphx]

ok, sounds and looks like you have some issues that are common and easy for you to fix.
There is a science to all of this. an hvac pro in your area really can do a good job of helping you, if you choose that option, but you can do this yourself if you want to ( I did).

so there are a couple of things the folks here will need to know to really help you.

1. how big is your current hvac system... I am guessing 1400 sqft in Cali,, maybe 2 tons, maybe 3 tons. The size is important because larger the system, the more air it will try to push around. The larger the system the larger the return grill (s) have to be!! And the larger the ductwork has to be. if the return and/ or ducts are too small, your system will be choked, costly to run and may wear out the compressor, indoor fan motor etc before they should.
2. design of the duct work. We need pictures or a drawing of how your duct work is run in the house and what its made of. We need to understand the type, sizes and design in order to make sure that the current duct system can provide the proper CFM and that it is delivered to the various room correctly. The proper cfm is also related to register size and how the registers "throw" the air across the room, thus mixing the air.

after all that we can see what can be done about returning air to the system with the bedroom doors closed.

lets start there and see what we have.

bob in phx