Venting From One Room to Another Through a Round Duct.

This could be a crazy thought but hear me out. I have a 18'x24' kitchen that was an add on which has a dirt crawl space. Also in this crawl area is a room in the basement that went under the old kitchen but is only about 10'x12'. The kitchen floor is all tile so that would be a great candidate for floor heat. I believe that when I install my boiler in another section of the basement, it will get mighty toasty in there judging by how hot it keeps my barn. So I was thinking of a way to dissipate a little heat from the room that the boiler will be in by running say a 8" round duct with a in the duct fan going from my boiler room to the crawl space under the kitchen. Do you think this would give me a little floor heat or would I be better off just running a PEX zone under the kitchen floor? Just thought it might be a quick easy plan to spread some of that boiler heat around and my kitchen is usually 5* cooler than any other room in the house.

It's easier and more effective to move water than air, you would have to also have a return duct going back, some way to control the fan, unless on 24/7. If the basement sections are all open, the heat from the boiler will dissipate everywhere, and the kitchen floor will warm, unless there is a wall seperating these rooms, if your boiler is truly shedding this much heat, you should really look into insulating it more before your done installing it.

Infloor heat done correctly is very expensive to install, might be cheaper and easier to just install a cast iron radiator in the basement room under the kitchen...

If you just use a duct for the heated air, I think most of the heat you pump in the crawlspace will be negated by the cooler temp of that dirt floor. High high is the clearance in the crawlspace and do you have easy access to it through a nice wide opening?

If you pump air into the crawlspace you will notice a small improvement in your kitchen. little investment ,little return. If you do the work yourself, $1000 max investment( more like 600>800) you could have a huge jump in enjoyment with infloor heat!

pex pipe $.50/ft $100
pump $120
mixing valve?? $100
insulation( shouldnt be counted here as it should be there either way) $120
what am I forgetting <$250 ?

does this help you make a decision?

waldo

All of the above, Plus wrap the boiler in a nice blanket of insulation.

waldo lemieux wrote: what am I forgetting <$250 ?
waldo

you forgot the payoff.....

Bare feet on a warm tile floor after coming in from getting rid of snow from the driveway on cold day in February........Priceless! :punk:

titleist1 wrote:If you just use a duct for the heated air, I think most of the heat you pump in the crawlspace will be negated by the cooler temp of that dirt floor. High high is the clearance in the crawlspace and do you have easy access to it through a nice wide opening?

It's a weird setup, there is about a 16" gap from the top of the old walls to the bottom of the new floor joists. So it's a pretty hodge podge setup that until now have not paid much attention to. Maybe I should?

titleist1 wrote:

waldo lemieux wrote: what am I forgetting <$250 ?
waldo

you forgot the payoff.....

Bare feet on a warm tile floor after coming in from getting rid of snow from the driveway on cold day in February........Priceless! :punk:

We have a toe duct that blows across the floor to the island where the sink is and let me tell you it is a wonderful spot to stand! I could not imagine how sweet it would be to have the whole floor that way. Also as mentioned, it's usually at least 5* cooler in there. If I were to do under floor heat, would I just install another thermostat in the kitchen to control that?

waldo lemieux wrote:If you pump air into the crawlspace you will notice a small improvement in your kitchen. little investment ,little return. If you do the work yourself, $1000 max investment( more like 600>800) you could have a huge jump in enjoyment with infloor heat!

pex pipe $.50/ft $100
pump $120
mixing valve?? $100
insulation( shouldnt be counted here as it should be there either way) $120
what am I forgetting <$250 ?

does this help you make a decision?

waldo

This would be a very nice winter project if I can get this boiler setup and running after I move it!

McGiever wrote: wrap the boiler in a nice blanket of insulation.

I will see what happens when I get in running in new location, may need to do this

I'm picturing a dirt floor 16" below your kitchen floor?

Right now and regardless of how you go, get some heavy mil plastic sheeting, cover that dirt, right up to the side walls and lay some foam insulation on it.

Ideal case would be a complete floor of foam without gaps and all taped up. Reality is laying some 1" or 2" sheets of foam on top of the heavy plastic can get you some quick and simple bang for your buck

Better yet, put the plastic down on the ground as mentioned above, fill your floor joist cavities with fiberglass insulation (cheap), and then fasten the 2" foam board on the bottom of your floor joists, seal up any cracks, wire passes, etc, with spray foam, and live it up!

The main issue would be adding heat to the floor/room later. You'd really want to have it installed before doing the last suggestion. The first suggestion would get you results quickly and give you time to think about the type of heat you want to install.

Hope this helps!

CoalisCoolxWarm wrote:I'm picturing a dirt floor 16" below your kitchen floor?

Right now and regardless of how you go, get some heavy mil plastic sheeting, cover that dirt, right up to the side walls and lay some foam insulation on it.

Ideal case would be a complete floor of foam without gaps and all taped up. Reality is laying some 1" or 2" sheets of foam on top of the heavy plastic can get you some quick and simple bang for your buck

Better yet, put the plastic down on the ground as mentioned above, fill your floor joist cavities with fiberglass insulation (cheap), and then fasten the 2" foam board on the bottom of your floor joists, seal up any cracks, wire passes, etc, with spray foam, and live it up!

The main issue would be adding heat to the floor/room later. You'd really want to have it installed before doing the last suggestion. The first suggestion would get you results quickly and give you time to think about the type of heat you want to install.

Hope this helps!

I guess I never really gave it much thought but I can see this as being a huge heat loss. I need to address this at some point, sooner the better.

swyman wrote:I guess I never really gave it much thought but I can see this as being a huge heat loss. I need to address this at some point, sooner the better.

Yeah, the things we look at every day we don't always see

One of the reasons a forum like this is quite helpful when bouncing ideas off others.

About your dirt floor....

Moisture is going to be your killer here. If you put just fiberglass on the floor, it will seem great...for a few months or even a year, then you'll start to notice the dampness and maybe mold on the paper.

Heavy mil plastic down first will cut that out a lot, depending on the rest of the space and how well you seal up the edges. It also helps slow or stop the natural flow of cold air from the ground.

Sealing up your floor is a good thing. You want to be diligent in making a good seal as airtight as possible to separate your floor joists from the ground and making the floor part of the conditioned, heated space.

2 inches of foamboard (R10) is the required thermal break thickness in our area for outside walls to prevent thermal conductivity and prevent condensation INSIDE the walls.

It may be different in an enclosed floor space?

Now that Lowes and HomeDepot are starting to stock the commercial/reusable cans of foam and carry the metal gun that goes with it, it's a simple and wise thing to get the foamboard in place (solidly mounted with large headed fasteners or firring strips or whatever) then seal up all the joints and holes with the foam.

This stuff is much better than the disposable cans and can be applied almost like a bead of caulking and after a few mins to skin over can be molded into the joints. Makes very clean and neat work

I think it has a wider working temp, too, which is helpful in a basement during the fall months

I believe you will be quite pleasantly surprised at the difference an insulated floor can make

I think my best route to go would be to pony up and do floor heat. I don't think it would be that bad of a project. That much of a heat sink would be wonderful!

When you start gathering parts for this build be sure to get big enough header/manifolds for all possible zones...plus room to expand in the future for just such additions as this.