Unconventional way to get fresh air intake with Hearthsone

[Jdesmaris]

I just moved into a large, tight, super-insulated house in northern Michigan. I was here for awhile last winter when it was 30 below F and all we had was propane heat (very expensive).

So now we're back in for this winter and I decided to install some sort of wood heat. House already had a 6" SS chimney that had never been used or hooked to anything. Also has an unfinished hearth. Raised wood platform with a 6" fresh air vent that was intended to be hooked to a small Lopi Answer woodstove. I just brought my Hearthstone Mansfield over and hooked it up. I discovered the 6" fresh-air vent had been wide-open all last winter letting cold air in. Also found out that Hearthstone wants over $100 for a fresh-air direct hook-up kit which I won't pay. So I'm trying something new - or at least new to me. I hooked up the 6" pipe from outside to a dryer-vent. It is lightly spring loaded. So if any negative pressure develops inside the house - it will open and let fresh air in. Otherwise - it will remain closed.

I was never impressed with this Hearthsone since I got it new. But now - it's working much better then it ever did before. I'm wondering if there had been something wrong with it all this time. When I moved 800 miles to northern MI from central NY - I took the stove all apart to make it easier to move. Took the top off, the firebricks out, baffles and fresh air tubes out, door off, etc. Well when I went to put it all back together - I discovered that there is nothing to hold the upper ceramic baffle support in place. I'm wondering if it had been in the wrong location all this years? Working great now. We'll see how it goes this winter I have a large wood furnace ready to install - sitting next to it if needed. So far it's been in the low to mid 20s F and the house has been plenty warm with just the Mansfield.

 

[DougA]

I can't see how you are hooking up the fresh air to the stove. Good to have photos of that too.

I just paid the $100. for the adapter for mine and in the process of hooking it up. I was cutting the 4" hole through the cement stucco a few days ago - that was fun without a 4" bit. My Equinox only requires 3", so I adapted down to 3" as the run for mine is less than 2'. I'm not sure what the purpose of the spring loading is when the stove is in operation. When you have a fire, you need the fresh air open all the time, on mine there is no other air into the stove that I am aware of other than the vent where the adapter goes.

 

[Charles1981]

It sucks but 100$ these days for all the trouble necessary to come up with an alternative fix? I would just plop down the money.

Gatta figure you spent a ton more than that on propane last year alone no?

 

[Jdesmaris]

I'm not convinced hooking up direct with the adapter from Hearthstone is any better then what I did. Maybe not even AS good. When I worked as a wood-stove installer back in the early 70s -fresh-air hookup was almost unheard of. We sold Thermo-control "air-tights" from Cobleskill, NY and they had no way of hooking cold air intake direct anyway. Most houses I'd gotten to work on were not very tight to start with. Plenty of "built-in" air intakes. As I understand it now -the idea of having a fresh air intake into the house is to insure the house interior never gets a negative pressure and thus, interferes with proper chimney draft. A problem in tight, well insulated houses. What goes out the chimney must come in somewhere. In this case - I am not sure yet if I can heat this large house all winter with just the Hearthstone Mansfield. That's why I've got a new large wood- furnace sitting next to it - ready to hook up this winter if I need it. If I DO hook up that furnace - there is no provision for a direct cold-fresh-air hookup anyway. With the spring-loaded vent I installed - it will let air in to the house when needed, near the stove or furnace - automatically - with no hookup. Someone asked why a spring? Why not? The vent is a one-way check valve. Lets air in when there is suction, ie. "negative pressure." When there is no need - the spring keeps it closed and no cold air comes into the house. Time will tell how this all works out. In my old farm-house in NY, where I had the Mansfield previously, I never had nor needed any sort of fresh-air connection to the outside. The old house had all the leaks that were needed, and more.

 

[DougA]

Fresh air hook ups are still pretty rare but are becoming more needed as houses are built super insulated and air tight - exactly as you describe yours. If you read though many of the posts on the forum, you'll see a fair number where draft is the main problem. An OAK can't solve everything but it does help if you have the clothes dryer on plus the furnace and maybe a bathroom vent. You solution will work just fine but I would rather hook the stove up directly so that the cold air is going into the stove, not the house in general.

I misunderstood your post. I thought you had hooked the air directly to your stove and wondered how you got that connection without the adapter.

There are a ton of people who disagree with an OAK and I am using one since I also have an air tight, super insulated house. My problem is that it will be impossible to put a fresh air vent in after the hearth is built, unless I want something that looks like crap. Easier to do it now and remove it if it causes problems.

 

[bholler]

I dont think it is a bad idea at all i just hope the spring is not to strong we are not talking about much pressure here i would be surprised if it could pull the spring open. But that is a guess i could be wrong

 

[OhioBurner©]

One of the advantages of the OAK is to not pull cold air from outside into your home, but rather channel that into your stove. For a basement install like you've done this probably isn't as big of a deal (in living area it could make the house seem colder, especially if your chair or sofa was in between the stove and where the outside air is leaking in. I too would be curious if there was enough pressure to open a spring loaded flapper, if your house is really tight I suppose there could be. My house is super drafty. But an OAK was required in my last instal, so I did anyhow, but can't really tell much a difference in drafts. If its windy there is going to be drafts in my home.

 

[Cory S]

I've burned for 20 years without an OAK, This year is the first, and I will never go back. Far too many benefits.