Heat circulation via an in-line fan

[vdecker]

Hi there,
I am trying to maximise the heat circulation from my insert into 2 bedrooms.
I have read previous threads https://www.hearth.com/talk/threads/1646/
on using HVAC to redistribute warm air and have to admit that I am not interested in that scenario. My bedroom happens to be sitting just above my furnace. I am a light sleeper so having a blower run all night circulating air is not very appealing! To make things worse, my aging heat pump is right under the bedroom window! You would figure that sleeping quarters would be an appropriate area of relaxation... what was the previous owner thinking?
So I am now considering alternatives that exclude any large mechanical devices!
But first, please allow me to describe the bubble I live in.


My house is an open concept high-ranch with a cathedral ceiling (1300 square feet). The floor plan is quite a simple two half design. The first half is the main living area (kitchen, dining and living rooms) with 16 foot cathedral ceiling. Room is 20 x 35 feet. I have a ceiling fan that really moves the air around well, even blowing it down the stairs to the basement. My small PE Vista more than adequately heats that room. The problem is getting it into the sleeping quarters overnight and avoid using the HVAC for circulation. The other half of the house is linked by a narrow hallway to 3 bedrooms


My stove is located at the far end where the ceiling is 9 feet high and slowly grades to 16 feet as you approach the center of the room I have 8x8 wood beams spanning across the room every 8 feet.

I have considered thru wall or room to room fans above my hallway door but I have found a couple negative issues with them.
1) They can be loud
2) They are apparent and can be eye sores
3) you loose a certain degree of soud proofness by making a hole in you're wall
4) warm heat enters the room at ceiling level which is not where you want it to be!

I have a table top fan blowing air into the hallway at night via the door. That kind of works but it is quite noisy and the heat still stays trapped close to the ceiling and will barely enter the bedrooms.

My most appealing alternative so far: Add an intake just above the stove and draw the warm air into the attic via an in-line fan and route 2 outputs into the sleeping quarters. Two bedrooms are joined by a closet so I figured I could run my duct inside a wall cavity and split the duct at floor level. All this wired up to a dimmer for variable speed control.

I have been monitoring ceiling Temps for a while now and can conclude that it is always around 6 degrees Celsius warmer where my anticipated air intake would be (about 5 feet in front of the insert at about 9 feet high, just in from of a beam) where heat really seems to be building up. If it's 25d Celsius at my breast level and 31 just at an arms length! I need to move that heat!


I live in Southern Canada so I don't need to describe what winter feels like
My attic has 16 inches of uniformly blown cellulose. I was planning on using 6 inch insulated flexible duct and bury it under the cellulose for extra insulation. I figure I would need 30 feet of duct. A typical 6 inch in-line fan can displace 250 cubic feet per minute very quietly.

Any comments on the usefulness of my proposed rig?
Any ideas on which in-line blower to choose if any? Fantech -Nutone-Broan


Any tips or comments would be greatly appreciated!!

Thanks

vince

 

[bfraymond]

Just a thought here, laws of thermo dynamics state that air moves from cold to hot. It will be an uphill climb from the get go. This may or may not work. If you crack a window in the room, it will create a draft and pull the air from the living room to the bedrooms. It may seem counter productive to open the window in order to heat but it might work. I haven't had to try it so I can't back it up. I heard it works though.

Brent

 

[begreen]

Oy, these same questions are coming in multiples per day. Spend some time looking at the dozens of similar threads.

Yes, you are correct, using the HVAC is not efficient. Using a jerry-rigged ventilation system can be dangerous. Ask yourself. What happens in the event of a fire? I certainly hope you'll never encounter this, but how will this jerry-rigged system work in the event of a fire? If uncertain, ask your local fire marshal or insurance company.

What about a silent, portable or a permanent electric baseboard heater in the bedroom? It can even be on a timer or digital thermostat that sets it back in the daytime.

PS: Thanks for the great description of your home. It sounds like a nice place. Post a picture of the PE for us if you can.

 

[vdecker]

Opening a window slightly is not really a viable option as all windows are a bit leaky. I have tried you're suggestion without any success.An entering cold draft always seems to prevail!

I did spend some time reading threads and did not find any solutions! I am figuring that some people have rigged systems that work and maybe they can share that info... I have 3 fire alarms +1 carbon monoxide detector currently set up in the house . I figured that if I had some outlets in my closet, it would be wise to have detectors close by.

 

[begreen]

I bet you found a whole bunch of - don't do that. We tend to be safety first here.

Ask yourself what a fan-fed blowtorch in your attic would do to your timely escape from a fire? Ask your insurance agent. It can be done, but would be expensive to do correctly with a well-insulated, metal pipe run with a fire-damper and detector to shut it off. But for the cost and the heat loss over the length of the run, it wouldn't be that efficient. Put in an electric heater and sleep safely and quietly.

It sounds like money would be much better spent on tightening up the house and getting those windows sealed properly.

 

[Homefire]

I just turn on the ceiling fan in the room with the stove and open the door to the stairs and other areas I desire heat.
That has work in my home for years and years.

 

[vdecker]

fan fed blowtorch (gulp)!
From a distance of 15 feet from my insert ? With that kind of scenario, fan or not, my house is toast ! What if I eliminate the fire spreading danger by putting my air intake closer to my cathedral ceiling peak? That is more than 30 feet from the insert. Like you mention, the issue would be heat loss through the length of my duct work. How can I calculate the heat loss through my ducts? I figured that with a powerful blower, a well insulated and airtight duct, I could actually transfer some heat.
You are right about the windows, most seals are shot and that will be big bucks to fix

 

[begreen]

If the room is on fire, where will the smoke and fire go first? Upward. It was the flex duct (not fireproof) and a continously running fan that got me concerned. I'm not saying it won't work at all, just that to do it right will be costly and an experiment at best. If the real issue is that there is major heat loss in the bedrooms, wouldn't that be a better thing to address first? Why the resistance to an electric heater? What are your electric rates?

When you say most seals are shot, is this the thermopane seal or the window's weatherstripping seals? If weatherstripping, For this winter, how about getting some of the clear 3M heat shrink film on the windows?

 

[fishercat]

Just my 2 cents worth. First thing I didn't do enough reading before I bought my stove. I figured that if I got a nice EPA stove I could heat anything. From what I gather it depends alot on how your house is made . High ceilings, where you put your stove etc.... What I thought I could do with mine was heat the whole house but for the most part if you put your stove in one end of the house and expect to heat the other end its usually not possible. What I should have done was bought a wood furnace which is designed for this kind of stuff. Although with the 3000 dollars I have spent so far there is no turning back. I guess I will have to use my electric heaters in certain areas of the house. My advice from what I have read in these forms is stay away from any sort of vents and use the stove for what its intended for. The form tends to be on the safe side but any advice seems to be from experiences people have had or from people that deal with this stuff day after day. Do lots of reading before you do anything.

 

[elkimmeg]

If I place a 20 ounce bottle under a running fawcet for 24 hours how many ounces will it hold?. Everbody is trying to move lighter warm air when the key is to remove the colder heavier air so the warmer lighter air can occupy the space. There are so many poorly designed HVAC application out there. It seems there are the proper amount of supplies, but somewhere the HVAC guys have a brain fart when it comes to the return volumes and locations. the key is drawing the cooler air out . Your design will have minimal gain if any. you are worried about sounds well that duct system might as well be a sound chamber of what goes on in the bedroom or stove room, there will be very little secerets in your home same with cutting holes in floors
increased sound transmission.

 

[vdecker]

Thanks for the advice Fishercat ! Need more reading! The electric baseboard would be a good solution and fairly cheap considering Quebec low hydro rates. Some of my thermopane seals are shot, just a few thought...
But i really wish I could find a simple way to gently move the excess heat a couple of feet over!

I believe my HVAC configuration is a pretty solid design (I was told by my HVAC maintenance guy), with large air returns in each room except for one. I should invite him over for another visit!

So Mr. Elkimmeg, do you have any suggestions ? Silent ones ? I haven't received many so far!

 

[Todd]

Try a box fan at the end of your hallway, on the floor pointed towards your stove. Maybe it will pull the cold air out of the bedrooms and create a warm air current above it.

 

[begreen]

Just cuz the thermopane seals have failed doesn't mean the windows are not insulated. Not visually pretty, and perhaps not quite as efficient, but they're still acting as a double (or triple?) pane windows.

So let me get this straight, tell me which is the "simple" way.
Alternative A:
Chop open a hole in the living room, buy 2 vent grilles, fan, wire up the fan, install fan switch, patch up that mess, install rect to round ductwork boots, install duct, insulate, cut fingers, clean up blood on walls when getting bandaid, crawl again through the attic (oops just put a foot through the ceiling), gagging on insulation dust, track that crap through the house, clean it up, cut another hole (oops, I didn't know there was wiring in there) in the bedroom, test theory, cut new holes to tweak system and patch old, and find out it ain't a great change. Or....
Alternative B:
Go down to the local store and buy an oil-filled Delonghi with built-in timer, plug in, enjoy. It will cost you less than $5 a month if your electric rates are low and it is turned off when no one is using the room.

 

[Marcus]

Hi Vince- Our floor plan sounds very similar to yours. Our bedrooms are off on a separate wing. I use a ceiling fan and fans in the corner of doorways to circulate the hot air. The small doorway fans are very quiet and work surprisingly well because they move the high up hot air and allow the cooler air to flow back at ground level. I have 2 fans in the corner of doors that blow heat into the bedroom wing during the daytime. Because we keep the kids bedroom door closed at night and for safety reasons, I do not use the fans going to the bedroom wing at night. Instead I have a zoned central air system and just heat the bedrooms with the gas furnace. In my experience, using ductwork to suck hot air from a room and blow it into another just does not work. It cools way too much to be useful by the time it gets to the other room.

 

[Marcus]

I highly recomend this fan- I have 4 of them running at the same time and they are hardly louder than a whisper:

(broken link removed to http://www.northlineexpress.com/detail~PRODUCT_ID~5CO-71925.asp)

 

[Roospike]

Vince D , Got a basement ? crawl space ? Why not do the same idea as what you were talking about except run the vents in the bedrooms at the floor and PULL cold air from the bedrooms and blow it into the stove room. This should pressurize the stove room and force warm air to the bedrooms from where its being drawn from.