Wind, wood stove, and hrv inlet
I have a very tight house with an HRV and a wood stove. The wind almost always blows at my house and I’ve noticed that, unless it’s burning perfectly, it sucks a little bit of smoke down on the leeward side. On days when this happens to be the side with my HRV inlet, I can intermittently smell smoke coming in through the vents. I burn dry wood, have a good draft and the chimney extends above the highest point of the house by a little over 2 ft. My neighbors are far enough away that they aren’t likely affected.
It occurs to me that on a naturally vented house, the wind would take the smoke away by pushing air into the house on the windward side and pulling air out of the house on the leeward (smoky) side, assuming a steady wind direction. I would like to get my HRV to be as effective at avoiding smoke ingress as natural ventilation. Has anyone else noticed this, or found a good solution? Is there a chimney height that will free the smoke stream from effects of the house in a strong wind?
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Replies
A higher chimney will better disperse the smoke, and is probably your best option here if you can’t relocate the HRV intake.
Bill
Hi Bill - Thanks for the reply. I plan to relocate the HRV intake based on my local "wind rose". It looks like north or maybe east would be the best option. There are still times when that will be problematic. I can extend the chimney another foot without adding exterior support. Do you think that would make a difference?
More height won’t hurt here, but my guess is that one foot is probably not going to be enough to make a noticeable difference. I’d think 5-10 feet would be more likely to make a difference. You need to get the chimney up above the air layer near your house that is more affected by the wind.
Bill
Sinarit,
I built a lot of Panabode cabins for a resort. Consisting of T&G squared logs they leaked a tremendous amount of air, and the mechanism you describe for naturally vented houses did occur with the smoke from the chimney. However the air-movement from the windward to the leeward side through the interior was strong enough that at the end of their burns the fireplaces would sometimes backdraft into the cabin as that air movement through the cabin overwhelmed the draw up the chimney. Opening a window on the leeward side made things much worse, opening one on the windward side cured it.
As you noted, as soon as you introduce mechanical ventilation, all that interesting natural air-movement is overwhelmed. The most sure fire cure is moving the intake onto one of the other three faces of the building.