OAK not necessary?

[RKBAGUY]

A local dealer just told me that because I have an insert in an existing fireplace, that an OAK isn't needed because in his opinion there's ample downdraft from the chase because the chimney couldn't possibly be sealed tight enough to create a barrier, and piping in additional airflow wouldn't do anything for me.

Any thoughts on this? It rather flies in the face of everything I've read here, but on the other hand, it does sort of make sense.

 

[Peterfield]

I was told essentially the same thing from my dealer. I challenged him but he sounded very confident in his explanation it isn't a necessity in my fireplace installation.

 

[fmsm]

I have 2 inserts, your dealer is wrong! There is a huge difference! And mine are sealed at both the top and bottom.

 

[bags]

Chickenman &smfm are BOTH right. Maybe the dealer likes to do the quick and dirty. Get in... Get out... Get paid FAST. Don't know the installer, but I am not sure your best interest is looked after either. Just my .02 cents. Get another qualified professional's opinion. Go with your gut. Advice is always FREE here.

 

[Wilbur Feral]

Chickenman &smfm are BOTH right. Maybe the dealer likes to do the quick and dirty. Get in... Get out... Get paid FAST. Don't know the installer, but I am not sure your best interest is looked after either. Just my .02 cents. Get another qualified professional's opinion. Go with your gut. Advice is always FREE here.

Good advice. There are some great stove dealers in the world, including some on this forum. And then there are the other [insert large % here]. Bottom line is that if the chimney is not sealed it is leaking heat from your house, and if it is, you need an OAK. The real solution is an OAK and a sealed chimney around the vent.

 

[lagger]

curious as what defines a "sealed" chimney.. my installer also could not be persuaded that he should or needed to hook up the lopi agp insert OAK in my zero clearance FP was necessary, he insisted it is not needed, the install included running a 4" pipe up the existing chimney with a cap at the top to size it correctly, the cap was sealed with silicone.. I may have some one install the oak if possible next spring, so far the stove is running just fine with out one but the season is young and the temps are pretty moderate so far. Not much chance to run it after the April 20124 install, went through maybe a dozen bags of NEWP before the heating season ended.

 

[TimfromMA]

OAK is seldom required but always a good idea.

 

[Ctcarl]

My place said they wouldn't do it unless a problem.So it's my second season and stove seems to run good.From my research a OAK is a good thing to have.i tried contacting the guy to do a side job this summer he was to busy.maybe next year.i will get one

 

[Don2222]

A local dealer just told me that because I have an insert in an existing fireplace, that an OAK isn't needed because in his opinion there's ample downdraft from the chase because the chimney couldn't possibly be sealed tight enough to create a barrier, and piping in additional airflow wouldn't do anything for me.

Any thoughts on this? It rather flies in the face of everything I've read here, but on the other hand, it does sort of make sense.

I have installed quite a few inserts ranging from a 25-EPI Englander to a Harman P52i.

We always run two liners, A 4" fpr the flue exhaust and a 3" for the fresh air to two chimney caps, the flue cap being taller to prevent blow back.

Then we use Roxul 100% Fire Proof rock wool insulation to completely seal and insulate around the liners on the damper shelf.

This keeps warm heated air from going up the chimney and keeps the house alot warmer wether the stove is on or off! ! !

Yes, we seal the chimney top also!

 

[Wilbur Feral]

See Don222's answer above, for a good example of a sealed chimney (assume they are sealing the cap at the top as well, of course).

As for whether a person's stove will "run right", that's NOT the issue. Yes, you will almost certainly have enough air for combustion. It's how that air is supplied that's the issue, and a dealer that says they will install an OAK "only if there's a problem" is either a lazy crook or just ignorant of how air is exchanged in a home.

Combustion air does not magically appear. If you have a blower pushing already-heated air through your stove and out a vent to enable combustion, that air must be replaced from somewhere (or your house would quickly become a vacuum). Without an OAK, that "somewhere" is from outside, with cold air that mixes with already heated room air, because it's being drawn in from all the tiny little cracks in a home, at a much faster rate than would normally occur, because you are blowing it outside with the combustion blower. And because those cracks are basically all over your house rather than being just a direct pipe to the outside and into the stove (which is all an OAK is), that cold outside air will require heating, which will require more of your hard-earned dollars in the form of fuel (i.e., more pellets).

Some dealers clearly didn't do well in physics class, and clearly know little about how a home is designed to perform. And some folks here are paying for their dealer's ignorance, laziness or worse.

 

[fmsm]

I have installed quite a few inserts ranging from a 25-EPI Englander to a Harman P52i.

We always run two liners, A 4" fpr the flue exhaust and a 3" for the fresh air to two chimney caps, the flue cap being taller to prevent blow back.

Then we use Roxul 100% Fire Proof rock wool insulation to completely seal and insulate around the liners on the damper shelf.

This keeps warm heated air from going up the chimney and keeps the house alot warmer wether the stove is on or off! ! !

Don is 100% right. Not only in his answer but in what to look for in a company to do business with. He does it right and you should settle for nothing less.