Major problem need advice asap

[matt60j]

OK here is the issue. I have a berm style house in central MI. My crawl space is my duct work, meaning I have a downdraft furnace that intakes on the top and blows strait down, then the air is forced back up through the vents in the floor. Very efficient. I consume 350-400 gallons of LP a year. Problem is its damp down there this year. The base is pea stone with plastic over top. Sidewalls are insulated and covered in plastic. My family has MAJOR allerergy problems and I want this space CLEAN and SEALED. How do I do it? I don't want to run the A/C till its done because I am just going to disturb the air and circulate ****! Please help. -MATT

 

[p_mori7]

The furnace just blows into the crawl space ? Then the air from the crawl space migrates up the vents by convection ?

Maybe I am not understanding your post...

 

[matt60j]

The furnace just blows into the crawl space ? Then the air from the crawl space migrates up the vents by convection ?

Maybe I am not understanding your post...

Exactly. Furnace has no duct. Blows straight down, pressurizes crawl space. Ground floor has vents that are open to the crawl space. Second floor has has duct work that is just an open end of the duct terminated in the crawl space. Works great in winter. My A/C coil is on the bottom of the furance. Not so efficient. So installed a booster fan on the duct work (in the crawl space) and wired it to run when the furnace runs. Works great and evened out the temp to within 2-3 degrees. Before it was a 8-10 degree difference. -MATT

 

[fury9]

I can't imagine the mold down there, that which you describe doesn't seem right, sounds like a total waste of fuel to me? Yet you say it's very efficient? Sounds like you need a hvac system with duct work, and a slush coat of concrete with drain tile and two sumps in the crawl

 

[matt60j]

I'm not describing it right i guess. It is extremely efficient. Costs me $800 to heat for the season. Saginaw Bay area MI. Cold, windy etc. Its air tight but air tight with the ground. -MATT

 

[matt60j]

A coat of concrete will just wick the moisture. Maybe new vapor barrier then concrete? But then we smell concrete forever, or at least a very long time??? Thanks. -MATT

 

[fury9]

What filters the air? If it's just blowing into the crawl? I have never seen or heard of this system, maybe I live under a rock, AFIK concrete doesn't smell for long at all

 

[Rookie2]

they make metal insulated duct work ,or flex duct. probably a days work by a hvac contractor.

 

[p_mori7]

OK.

So you have a filter that is screening the air flowing into the furnace, and it is exhausting hot air into the crawl space. Sounds like the crawlspace floor is not insulated, nor is the main floor.

As far as allergies go (I suffer as well), I think the best solution is to duct the hot air coming out the furnace to the vents for the main & second floor. The heated air needs to stay clean. You can always route a vent into the crawl space to keep it warm.

I think the hot air from the furnace is cooling somewhat in the crawl space before convecting up the vents, this might be causing some condensation (maybe mold) on the plastic sheeting above the gravel floor. In the winter, I would guess that the gravel floor is quite cool.

Could it be that the furnace was installed that way to save $ on ductwork & floor insulation ?

I know convection heat works great to heat a house...we had a wood slow combustion stove in the basement of a prior house...and we had created pathways for the hot air from the basement to creep upwards throughout the house...also acted as additional return air for the oil fired furnace that was in the basement...the furnace was ducted to all the vents on the main floor & basement (no second floor back then).

 

[matt60j]

FWIW i think something like a duralast roof but in my crawl space????

 

[SCTony]

Call Terminix- (seriously). Look into having a vapor barrier installed. Terminix and others provide this service. I have been under a few homes that had this installed and it makes for a nice clean area. Terminix appeared to do a better job of those I have seen- they taped and sealed the seams whereas another company did not. Terminix. Maybe that would help.

 

[fury9]

He doesn't have an insect problem, his FAMILY IS SICK, OP you might want to contact a hvac guy, and a good one at that. Do your research, don't hire a hack

 

[p_mori7]

A concrete floor will help...but as you stated...bare concrete creates dust eternally...and will not help allergies...if that concrete were then to be covered over with tile...that would make it a lot cleaner...but very $$$...right now the crawl space is being used as a plenum...if it is not clean, the allergens will spread everywhere with the convected hot air.

 

[fury9]

Imagine how efficnt that system would be if you had minimal heat/ac loss through insulated duct work VS> heat/ac loss being pressurized through a ******** crawlspace

 

[matt60j]

Imagine how efficnt that system would be if you had minimal heat/ac loss through insulated duct work VS> heat/ac loss being pressurized through a ******** crawlspace

I think its time to redo my entire system. I def here what you are saying. -MATT

 

[koditten]

I'm having a hard time wrapping my mind around this. Your house must be really dusty in the winter. Is it even leagal to do this?

Most crawl spaces around here are 50* or so. Your a/c would never run. You would just be moving cool air from the crawl space.

I hate to say it, but you can't do what you want without ductwork.

 

[philjafo]

First get ducts installed, like fury9 said if its good now, it can be great. Then look into uv lights, and ozone. As far as filters, when I've got a client with MAJOR allergies I recommend the perfect 16 hepa. Definetly not cheap, but single pass hepa filtration and the filters typically last for 3 years.

http://www.iqair.com/home-air-purifiers/wholehouseairpurifiers/perfect16.php

Here is a link to iqair, makers of the perfect 16.

 

[matt60j]

I'm having a hard time wrapping my mind around this. Your house must be really dusty in the winter. Is it even leagal to do this?

Most crawl spaces around here are 50* or so. Your a/c would never run. You would just be moving cool air from the crawl space.

I hate to say it, but you can't do what you want without ductwork.

It's actually an easy house to keep clean. The forced air is dissipated enough that it is a nice even low draft heat/cool. I'm looking for a fix and a duct seems like the only solution. I want a healthy family so money is not a concern on this one. -MATT

 

[matt60j]

What filters the air? If it's just blowing into the crawl? I have never seen or heard of this system, maybe I live under a rock, AFIK concrete doesn't smell for long at all

My Ceiling near the furnace has a cold air return. Has a 20"x20" grate with filter. The bedrooms all have a cold air return but they are unfiltered.

 

[brewchief]

I've run across a system or two like the OPs that use the crawl space as the supply plenum, it does meet code here in MI(or did when installed, I haven't looked it up in the code book recently). That said I think a proper ducted system will work better.

There are companys that do crawl space encapsulation, they completely seal the walls and floor with a very heavy plastic with provisions to remove moisture from under it.

Doing both would be the best case.

 

[Jackfre]

You might check out a local, to you, manufacturer of crawl space ventilators Their AirXchange unit might be of some help too.

www.tjernlund.com

 

[Highbeam]

They do that here, crawl space plenum. No adavantages other than keeping your plumbing warm and saving money on ducting. This is not a better way to build it is a lazy/jippo way to build.