Crawl spaces with combustion furnaces

[Tom Worth]

Hello,

I've heard the argument that a sealed crawl space is no different from a basement, and basements have furnaces. But I'm still confused even though (or perhaps because) I have visited all your recommended links. At least now I have been able to whittle the number of questions I have down to just a few:

1. Should a crawlspace that has a one-pipe combustion furnace have all the foundation vents sealed?

2. Advanced Energy linked me to www.crawlspaces.org, and they say, "Specify direct-vent("two-pipe") models to ensure adequate combustion air when fuel-fired appliances are used. All air for combustion should be piped directly from outside into the appliance..." What does that mean?

2. A friend told me that he was told by an HVAC expert, only sealed combustion heating equipment is allowed in a sealed crawlspace. What is "sealed combustion equipment"? Is that what a two-pipe furnace is?

3. Can I assume that the local installer will begin their visit by first telling me the type of furnace I have? Do we then discuss the options in the context of what ever local codes may be in play?

Thanks and I hope this helps others who may have some or all of the same questions.

[Crawl Space MD]

Hello,
All good questions. The direct vent unit you are asking about has a fresh air,or direct air supply to the combustion unit. If you have an older unit, single pipe, as you describe it, you could have an "enforcer" unit installed, this will supply fresh air to your furnace when the furnace turns on, and will only operate when the furnace needs that fresh air.
Your local CleanSpace Installer will be able to help you with any other specifics.
Thank you.
Crawl Space MD

[Tom Worth]

Thanks. Just two last questions. I can see that installing the Enforcer will provide combustion air required for older one-pipe furnaces. First, doesn't this defeat the purpose of sealing all the vents as we would now be introducing air in to the crawl space from the outside? If I go that route, will the installer include this component in the design plan and quote it with the rest of the encapsulation installation?

Thanks for you help.

[Crawl Space MD]

Tom,
Yes the outside air will be unconditioned, you can also have a continuous running air machine called the "crawlospher" installed by your CleanSpace installer. It is better to use conditioned air vs. unconditioned air. You local Dealer should be able to determine which is best for you.
Thank you.
Crawl Space MD

[Tom Worth]

Thanks so much for your patience and commitment to education through this valuable forum. One last follow up. As encapsulation is a considerable investment, and since I am not an expert (that should be clear from my questions), I need to know that my installer has been trained to address my particular situtaion, i.e., a one-pipe combustion furnace. Who trains my installer? Does their training insure that they will design my crawlspace encapsulation to include a way (e.g., Enforcer; "crawlospher"; etc.) to deliver the needed combustion air? Thanks again. TW.

[Crawl Space MD]

Tom,
You have alot of good questions. Our Dealer will give you the best system advise, and it will be up to you as to what you purchase for your home. Remember, the more complete the system, the happier you will be, and the better it will perform for your home.
Good Luck.
Crawl Space MD

[Tom Worth]

Hi Doc,

But I am still wondering about dealer traing because p:confused: roper combustion air is a serious matter and I wouldn't want to leave it to chance. That's why I needed to know if your delears were trained in this aspect. If not, should I be consulting with a HVAC contractor to coordinate with my dealer as we design the encapsulation system for my crawlspace. Thanks.

[Crawl Space MD]

Tom,
For your situation, call your hvac guy and have him coordinate with our Dealer.
Crawl Space MD

[Pat Ferr]

I'm in the same boat. I have an older furnace that is one pipe. I received promotional material from my dealer that says only sealed combustion equipment is allowed in the crawlspace once your CleanSpace system has been installed. Yet, the dealer didn't call this to my attention. Is that because dealers aren't trained to know this and is that why you recommended that Tom should involve his HVAC contractor before signing the contract?

Thanks. PF.

[Crawl Space MD]

Hi,
If the Dealer sent you information on it... then he did inform you. Our Dealers are trained and Certified, some of them are hvac guys (and gals), some have different types of techs on board, as well as other trades, electricians, plumbers, etc. I asked him (Tom) to check with his hvac guy because I did not know where he was writing from or who his Dealer might be. Tom had alot of good questions, and I knew he should get his second opinion for his peace-of-mind. It's an investment of money to fix your crawl space, and Tom was right in spending time making sure he was getting the best advise and products. I know that Tom will be a long-time, happy customer because of the upfront time he spent.
Thank you.
Crawl Space MD

[ruralvoice]

Regarding a natural gas combustion heater in my crawlspace. I am about to seal the space. My Amana unit, purchased last year, is direct vent with triple wall pipe for supply and exhaust--the unit is 90% efficient. The line goes to the outside. I assume this means it is a non-issue for the crawl space air. Please confirm. Also, I already have a Santa Fe Advance De-humidifier in the crawl space which I have installed. Is there any other need for "conditioned" air once I have basement systems seal the space? Thanks for your reply

[Crawl Space MD]

Hi,
If you have a direct vent unit, providing it was installed correctly, and are running a dehumidifier, you should have a great crawl space or basement.
Crawl Space MD