Adding a vent through a crawl space

[abrucerd]

EDIT: Crap, meant to post this in DIY... my bad.

Hi,

I originally posted this in the pellet forum (since I have a pellet stove), but thought I might get some good advice here too.

My house is a old new england colonial with an addition on one side, which is where my stove happens to be. The addition has vaulted ceilings, with one wall running up along side where the master bedroom is on the 2nd floor (see photo).

I’m considering putting a vent in the top of the wall of the addition, through a small crawlspace and into the bedroom wall (close to the floor) to help the warm air from the pellet stove get to the bedroom upstairs. I don’t have any existing ductwork in the house, and I've never done any type of ductwork myself.

Originally I looked at thru wall fans that seem ideal for this ((broken link removed to http://www.suncourt.com/Suncourt) ThruWall Fans.html), but those are not long enough to make it through my crawlspace (about 2.5 feet).

After researching, I'm thinking that flexible duct with a fan might work, but I'm not sure how wide the duct should be or how the duct fan would be hooked up to a switch (I'm not electrically inclined either )

Any advice or suggestions would be appreciated... Thanks in advance!

 

[smokinj]

Looks like a great spot to collect some warm air. Any ceiling fans in place?

 

[abrucerd]

Yes... one right above the stove. You can actually see it, but the blades are running full speed so it's hard to tell

 

[semipro]

I just completed similar work in our house. I found a fan was not really needed. Natural convection due to the density differences of the air will move the air.

You could put a wall register in each area with a duct boot and flexible ductwork to transfer the hot air. Its really pretty simple work if you're willing to cut holes in your walls/ceilings.

One note though, consider effects on fire propagation. There are fire vents (called fire dampers) available that will close automatically if temps get too high.

 

[Don2222]

Hello

If you go with 6" duct then Home Depot has a nice 6" InLine Fan real cheap.

That's is what I use to get the heat upstairs from my basement pellet stove. Works Great!

Also here is a nice wiring diagram I made for auto or manual fan operation.
With the switch in Auto mode the fan turns on the Line Voltage Thermostat if the Temp goes above 75 degrees to blow the heat upstairs. The fan is connected to the cooling contacts to work this way!!

If you click on the wire diagram to enlarge it, you should be able to see it ok.

On the wall control panel
The Top Switch is Auto Fan On/Off
The bottom switch is Manual Fan On/Off
The round knob is the speed control of the Fan. Too fast and the air will not be very warm.

 

[semipro]

Hello

If you go with 6" duct then Home Depot has a nice 6" InLine Fan real cheap.

That's is what I use to get the heat upstairs from my basement pellet stove. Works Great!

Also here is a nice wiring diagram I made for auto or manual fan operation.
With the switch in Auto mode the fan turns on the Line Voltage Thermostat if the Temp goes above 75 degrees to blow the heat upstairs. The fan is connected to the cooling contacts to work this way!!

If you click on the wire diagram to enlarge it, you should be able to see it ok.

On the wall control panel
The Top Switch is Auto Fan On/Off
The bottom switch is Manual Fan On/Off
The round knob is the speed control of the Fan. Too fast and the air will not be very warm.

Don, is that fan running on 115 VAC? If so, aren't thermostats of that type rated for 18-24 VAC? Maybe I've misidentified the thermostat.

 

[Don2222]

Hello

If you go with 6" duct then Home Depot has a nice 6" InLine Fan real cheap.

That's is what I use to get the heat upstairs from my basement pellet stove. Works Great!

Also here is a nice wiring diagram I made for auto or manual fan operation.
With the switch in Auto mode the fan turns on the Line Voltage Thermostat if the Temp goes above 75 degrees to blow the heat upstairs. The fan is connected to the cooling contacts to work this way!!

If you click on the wire diagram to enlarge it, you should be able to see it ok.

On the wall control panel
The Top Switch is Auto Fan On/Off
The bottom switch is Manual Fan On/Off
The round knob is the speed control of the Fan. Too fast and the air will not be very warm.

Don, is that fan running on 115 VAC? If so, aren't thermostats of that type rated for 18-24 VAC? Maybe I've misidentified the thermostat.

Yes, that fan is 120 VAC and the Thermostat is a Honeywell Heat/Cool 120 VAC Line Voltage thermostat T651A1269
The thermostat pic is below.

From Amazon I believe this is the new model see link
http://www.amazon.com/Honeywell-T60...ref=sr_1_1?ie=UTF8&s=hi&qid=1250214207&sr=8-1

Here are some on e-bay. Nice Price!!
(broken link removed to http://cgi.ebay.com/Honeywell-Super-Tradeline-T6051A-1016-HD-Thermostat-NEW-/250814820118)

 

[abrucerd]

Can I use that type of fan with flex duct, or does it need to be rigid?

 

[Don2222]

Can I use that type of fan with flex duct, or does it need to be rigid?

I prefer the rigid but the flexible should work also.

 

[nate379]

Line Volt T Stat. Used for electric heat/turning on/off a fan. Can buy at Lowe's for $20 on up depending on fancy of a model you want.

 

[Don2222]

Line Volt T Stat. Used for electric heat/turning on/off a fan. Can buy at Lowe's for $20 on up depending on fancy of a model you want.

Yes Nate but those T-Stats only have Heating Contacts. It depends upon what you want to do with the fan.

In my case I want the FAN to turn on when the air temp is ABOVE 75 Degrees, so I connect the fan to the Cooling contacts.

If you use a T-Stat at lowe's with only the heating contacts, then the FAN will turn on when the temp drops BELOW 75 Degrees.

 

[nate379]

10-4, wasn't thinking of it that way.

I put a water to air heater in my garage recently so that's where I knew about the T Stat.

 

[begreen]

I just completed similar work in our house. I found a fan was not really needed. Natural convection due to the density differences of the air will move the air.

You could put a wall register in each area with a duct boot and flexible ductwork to transfer the hot air. Its really pretty simple work if you're willing to cut holes in your walls/ceilings.

One note though, consider effects on fire propagation. There are fire vents (called fire dampers) available that will close automatically if temps get too high.

Agreed. If the bedroom door is left ajar so that the cool air can descend back downstairs this should convect naturally without a fan. You might even consider putting a small window up there. The reason being that it will allow you to regulate the air flow, it will bring in more light to both rooms and when not heating you can close it off for noise reduction.

 

[semipro]

Hello

If you go with 6" duct then Home Depot has a nice 6" InLine Fan real cheap.

That's is what I use to get the heat upstairs from my basement pellet stove. Works Great!

Also here is a nice wiring diagram I made for auto or manual fan operation.
With the switch in Auto mode the fan turns on the Line Voltage Thermostat if the Temp goes above 75 degrees to blow the heat upstairs. The fan is connected to the cooling contacts to work this way!!

If you click on the wire diagram to enlarge it, you should be able to see it ok.

On the wall control panel
The Top Switch is Auto Fan On/Off
The bottom switch is Manual Fan On/Off
The round knob is the speed control of the Fan. Too fast and the air will not be very warm.

Don, is that fan running on 115 VAC? If so, aren't thermostats of that type rated for 18-24 VAC? Maybe I've misidentified the thermostat.

Yes, that fan is 120 VAC and the Thermostat is a Honeywell Heat/Cool 120 VAC Line Voltage thermostat T651A1269
The thermostat pic is below.

From Amazon I believe this is the new model see link
http://www.amazon.com/Honeywell-T60...ref=sr_1_1?ie=UTF8&s=hi&qid=1250214207&sr=8-1

Here are some on e-bay. Nice Price!!
(broken link removed to http://cgi.ebay.com/Honeywell-Super-Tradeline-T6051A-1016-HD-Thermostat-NEW-/250814820118)

Good to know. I've used a very quiet ceiling-mounted bathroom fan to do something similar before. I used an attic ventilation fan control as the thermostat but its not quite as presentable as the one you used.