Air Circulation

[RobinJoe]

We are about to order a Lopi Declaration for our 1500 SF rambler with a 1500 SF unoccupied basement. The house hase a gas-fired furnace and forced hot air. The fireplace is in the Living room at one end of the house, the Master Bedroom is at the other end of the house.

Last year I was using a "FirePlace Radiator" which heated the Living Room very well, but didn't do much for the rest of the house. I was hoping the Central Heating return (in the hall about 15' from the fireplace) would suck in enough hot air to distribute the heat to the rest of the house, but it didn't.

Now I'm concerned that the Lopi Declaration will turn our Living Room in to a sauna, while the rest of the hause remains too cool. Here is my proposed solution:

Run a flex-duct from the living room to the Master Bedroom with an in-line fan in the middle and filters to clean the air for my wife who has allergies. The products I have in mind are as follows:

12 X 12 Filter Grille (Living Room) (broken link removed)
12 X 12 X 10" Ceiling Box (Living Room) (broken link removed)
Round Reducer 10" to 6" (broken link removed)
6" X 25' Flex Duct 2X 25.39 = (broken link removed)
In Line Filter (before the fan) - http://www.hvacquick.com/catalog_files/Fantech_FB_Filter_Box_Catalog.pdf
6" Inline Fan - (broken link removed)
10 X 10 Diffuser (Bedroom) (broken link removed)

The duct run would be about 25' long.

I was considering increasing the duct and fan to 8", but the In-Line filter is only available in 6". Maybe this would still be a good idea to reduce resistance for the length of the duct, but I don't want the filer box to howl or whistle because it's too small.

Any comments or suggestions?

Thanks,
Joe

 

[fossil]

If you can, take air from the floor of the bedroom in the most remote corner, and move it into the space where the insert is located. Warmed air from the heated space will find its way back into the bedroom to replace the air being removed by the fan. That circulation pattern is about your best shot. More effective than trying to move warm air into the bedroom. Rick

Edit: Dunno what your budget is, but there are much better fans available...quiet, variable speed: (broken link removed to http://www.fantech.net/fg.htm)

 

[RobinJoe]

I like the idea, because it would increase the pressure in the Living room. It would also draw the warm Livingroom air past the return air grille which would help distribute the warm air to the rest of the house.

Unfortunately, the basement is finished, so running ducts through the floor will be impractical. I know it wouldn't be as effective, but do you think blowing the air from the Bedroom to the Livingroom ceilings would be better than the other way around?

I would also like to filter the air before it gets to the master bedroom. This may be over-kill, but my wife is VERY concerned about her allergies.

 

[RobinJoe]

Fossil, I saw the fantech fans, and they look awesome, but I thought I'd try out the cheap ($35) in-line fans first to see if they work before investing a couple hundred dollars for the Cadillac of fans.
(broken link removed to http://www.fantech.net/fg.htm)

We might find that we need to abandon the whole system (Wood Stove and all) if my wife's allergies can't handle it.

Joe

 

[fossil]

If the best you can do is take air from the bedroom ceiling, give it a shot, it's better than nothing. Get to the most remote bedroom corner and put the return register there. The fan should take a suction on the bedroom, so the in-line filter will be filtering the air as it leaves the bedroom on its way to the living room. The register in the living room then functions as a "supply" register (air issuing out of the register), and can be located pretty much wherever you want...but it should be about as far as it can be from where the newly established circulation pattern finds its way out of the heated space on its return trip to the bedroom. You don't want to "short circuit" that loop Rick

 

[Todd]

See how the declaration works out before you go installing duct work and fans. It may be fine since it has a blower to push the heat out. If you have a problem then think of ways to move the cooler far room air towards the stove. Sometimes a box fan on the floor works wonders.

 

[RobinJoe]

I believe the FanTech fans are Centrifugal whereas the cheap Home Depot fans are Axial. Here is an interesting third alternative called Mixed flow:
http://www.hvacquick.com/catalog_files/solerpalau_TD_Extended_Catalog.pdf
On page 2, they compare the three fan types.

Since my proposed system is circulating, and the length is only 25', I am hoping the static pressure won't be too much, and that the axial fan would be the higher volume, and quieter option.

I'm not an expert though, so I may be completely wrong.

 

[Redox]

I wouldn't do anything until you get the stove installed and see how it does. As others have mentioned, it is easier to move cold air out of the room than push hot air into the room. The furnace fan may do a better job of moving the heat around if the return is up high. If it is down low, you may be able to move it up fairly easily by cutting a new return up high and closing up the low return, assuming the wall cavity is open. Furnace fans can use a fair amount of power, but probably not more than a dollar a day (on low speed). It's even better if you have a whole house air cleaner on the furnace for the allergies.

An axial fan is not going to develop enough static to overcome the resistance of anything more than a cheap fiberglass filter, and the centrifugal fans use a lot more power and are more costly. See how you do without it before you start making changes. It might suprise you now that you are getting a real heat source. ;-)

Chris

 

[begreen]

I'm with Redox. I would take the low tech approach this season and learn what works. Get a cheap box or table fan and put it in the hallway or master bedroom doorway facing toward the stove. Let it push the cold air towards the stove and see how that works. It will allow you to experiment with the ideal setup and could save you a couple hundred in the meantime.

 

[smokinj]

here is the one i went with it will take heat up to 180 (broken link removed to http://cgi.ebay.com/Vortex-PowerFans-8-Inch-Inline-Exhaust-Fan-Duct-Blower_W0QQitemZ250125878703QQcmdZViewItem?_trksid=p3286.m20.l1116) and this thing rock!

 

[RobinJoe]

Thanks to everyone for the tremendous help. I especially apreciate Redox's reply about the static pressure from the filter.

I tried a box fan on the floor when we were using the fireplace radiator (broken link removed), but it was noisy and didn't seem to do much good. And the wife and cats hated it. Maybe I just need a better (quieter) box fan.

The existing return-air grill in the hall is up high, so that should help.

As suggested by so many of you, I will wait to see how things go after the Lopi is installed before I do anything. If I do install the duct/fan, I will start with a simple system (duct/axial fan) and build to it from there (filter/centrifugal fan. etc.).

Thanks again,
Joe

 

[begreen]

You will be in another ballpark with the Lopi. The blower on the stove will assist circulation as well.

When you tried it, were you blowing the colder hall air towards the source of heat? It doesn't have to be a box fan. A 12" table fan works well too. Run the fan on low. We can't even hear the fan running at that speed. Listen to a few at the store and get your favorite at the end of summer when they are at half price.

 

[RobinJoe]

The Fireplace Radiator I used last year had a blower too, but I suppose the Lopi will have a better one.

I didn't use the floor fan much last year because of the noise. Not enough to know whether it was effective.

 

[woodburn]

You can check out www.smarthome.com They have some good stuff.

 

[Redox]

The Fireplace Radiator I used last year had a blower too, but I suppose the Lopi will have a better one.

I didn't use the floor fan much last year because of the noise. Not enough to know whether it was effective.

The Lopi is going to have more sheer heating horsepower than the fireplace. I think you will be surprised at how well it will do.

Regarding the portable fans: those cheap box fans are a joke as far as airflow and noise are concerned. If you really want to move air, look into one of the high velocity types from Lakewood or others. They are 3 times the price but move 10 times the air. They are more energy efficient than the shaded pole motors on the cheap fans and are very quiet on low speed. I would try putting it at the end of the hallway outside the bedroom and point it down the hall (along the floor) toward the stove.

Don't worry about the cats; they will be sacked out on the sofa in front of the stove and the wife will probably like the lower fuel bills. Allergies can be a problem, but the stove shouldn't really contribute to them.

Chris

 

[RobinJoe]

Our Lopi Declaration is in place, and it puts out a lot of heat. To recap our situation: Our house is a large rambler (ranch). The fireplace is in the Living Room, and the master bedroom is at the opposite end of the house down a long hallway. About 35-40' from the stove to the bedroom door. Even on marginally cold nights (40 degrees F) the heat from the stove only got about 1/2 way down the hall.

What I did was get 25' of 8" flexible insulated duct ($30), an in-line fan ($36) two registers ($45), wiring and a switch.
(broken link removed to http://www.audubonsupply.com/browse.cfm/4,4834.html)

The duct runs in the attic from the master bedroom's bath to the living room. I am blowing the cool air from the master bedroom/bath in to the living room. By creating low pressure in the bedroom, and high pressure in the living room, the warm air that's already going half-way down the hall is encouraged to go the rest of the way to the bedroom.

I mounted the fan at the midpint, and the fan noise is almost inaudible. The fan is rated at 210 CFM, but I'm sure the flow is less than that due to resistance in the duct. It may be 120-150 CFM, but I don't know how to test that.
(broken link removed to http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId;=-1&catalogId=10053&productId=100080191)

The master bedroom now stays comfortable at about 68 degrees, and the living room is cooled down to about 80 degrees. It was getting too hot in the living room before. A side benefit is that the humidity from the the master-bedroom shower distributes to the rest of the house.

Joe

 

[fossil]

Good to hear that your hard work installing that auxiliary air movement system seems to be paying off, Joe. And you set it up to move the air in the correct (and code-allowable) direction. I now have a similar system installed, except my ductwork & fan are in the crawl space beneath the house. It can take a suction from floor registers in any (or all) of the most remote corners of three bedrooms, and send that air to a register in the brick hearth just behind our freestanding woodstove in the great room. Although work on our home is still in progress, so we're not yet moved back in, I saw the sytem work for the first time yesterday. The plastic drop cloth that still envelopes our stove was blown up like a balloon...so I know the system's moving air and moving it in the correct direction. When we have no guests, we can shut two of the registers, so it will serve just our MBR. When we finally get moved back in and I get a chance to put it to the real test, I'll post the results. Anyway...god job on the deisgn and implementation, Joe. Rick