do vented gas FP's create moisture ?

[cvcman]

Again we are deciding IF we want a gas fp. I know they say the unvented ones are bad but ..

1) any problems with people with asthma with VENTED models ?

2) do Vented models create extra moisture in the house ?

[jtp10181]

A direct vent will not directly interact with the air in the room at all. All combustion air comes from outside and 100% of exhaust goes outside. You may get some burning dust smells and anything else floating in the air in your house can get singed and create smells. About the same as if you use a forced air furnace for heat.

Don't even bother with a B-Vent fireplace.

[logdoc_rob]

Any moisture produced by vented gas fireplaces will go up and out of your chimney along with any other combustion byproducts.....that is IF your fireplace vents properly. Also, along with moisture, your already heated house air will exit your home thru your chimney and be replaced with cold outside air unless your firebox has it's own makeup air vent.

Living in NY, your best bet may be a direct vent fireplace. They look nice, are fairly efficient and do not have the indoor air quality issues that other fireplace types have.

[cvcman]

how much heat goes up the chimney when its running

[logdoc_rob]

I am not sure what percentage of your household heat goes up the chimney, but you lose around 600 cubic feet per minute out of your home. Vented gas logs are around 15% efficient.

[cvcman]

so if you take outside air then none of the room air leaves ?? Whats the eff of a vented model using outside air ? Any better lines to look at ?

[logdoc_rob]

If you are looking for heat, then vented is not the way to go. They are mainly just for decoration.

A direct vent unit would be your best alternative. Try Heat-n-Glo, they have some fine units.

[cvcman]

??? If im looking for heat VENTED is NOT the way to go ?? So I should go non vented ??

Whats the diff with direct vent ??

Can I go direct vent if its bumped into my attached garage and piped into exsisting chimney ??

[gary_g]

??? If im looking for heat VENTED is NOT the way to go ?? So I should go non vented ??

Whats the diff with direct vent ??

There are 2 types of vented: B vent, and D vent.

B vent is for show, no heat, and you loose heated house air up thru the chimney.

D vent is a heating appliance w/sealed glass doors. Takes outside air for combustion and vents thru a concentric pipe (pipe within a pipe).

I am not a pro, and I don't have any experience with these units, but that's my understanding of the 2 types of vented gas fireplaces.

Take care.

[jtp10181]

logdoc, you are confusing the crap out of this poor guy.

A DIRECT VENT gas fireplace works as I already said, 100% of combustion air from outside 100% of exhaust outside. Best option for indoor air quality. These can be built into the wall or an insert which goes into an existing wood fireplace. These are very efficient, ranging from 50-80%.

A B-VENT gas fireplace will use room air for combustion, and possibly also outside air. In theory 100% of exhaust goes outside, but has the potential for spillage. These can still be very efficient but pull air out of the house.

A VENTED GAS LOG would be something that goes inside of a wood burning fireplace, it is not efficient and for decoration only. Highest potential for spillage and worst for indoor air quality.

I hope that clears that up.

[cvcman]

very efficient 50-80 % Thats good ???

[jtp10181]

For a gas fireplace, 80% would be on the high end. Some of the cheaper ones are not as good. There some even higher but they are condensing and use PVC for a vent, totally different setup.

If you want to get a lung vented fireplace, you can get 100% efficient, but is it worth the trade off?

[jerryd_2008]

logdoc, you are confusing the crap out of this poor guy.

A DIRECT VENT gas fireplace works as I already said, 100% of combustion air from outside 100% of exhaust outside. Best option for indoor air quality. These can be built into the wall or an insert which goes into an existing wood fireplace. These are very efficient, ranging from 50-80%.

...

My newly installed, DIRECT VENT, 38,000 Btu, Heat & Glo fireplace insert is rated at 77% AFUE. That compares very well to my new 80% AFUE NG furnace.

Unless you intend on heating your house with it as a few people do, it is mostly for ambiance and maybe one room comfort. Extreme AFUE efficiency isn't the issue. If efficiency is your issue, then consider just how much NG the standing pilot uses per month. I believe I figured that just the pilot light might use 10-11 CCF/month of NG.