Monday, November 3, 2008

A Better Draw


A short while back, October 11, to be precise, I wrote about the need to improve the heating in this house. So as not to repeat myself, that posting is here. One of the issues we turned up (here) was that the lower floor wood stove insert didn't have a chimney liner, so it didn't draw well, and because of that, it dumped ash and smoke into the house whenever the door was opened for reloading. 

I contacted several heating and chimney companies to get bids for dropping in a liner. The first thing that turned up was that some quoted the job with an insulating sleeve, AKA a "fire wrap," and others didn't. This affected the price by a few hundred dollars. 

The point of the insulating sleeve is twofold. First, it keeps the hot stainless steel liner pipe out of direct contact with the inside of the chimney, especially in the tight area going through the damper opening and around the smoke shelf. As it was explained to me, while the inside of the chimney throat has a masonry liner to protect the wood surround from overheating, there is no way to tell how thick those bricks are. If the intensely hot metal liner is pressed directly against the masonry, it can make those bricks so hot that any wood they are in contact with can crystalize and potentially catch fire. By surrounding the liner with an insulating sleeve it protects the masonry from the heat. 

The second reason why an insulating sleeve is a good idea is that the metal liner will be insulated from the cooler air in the chimney for its entire run, and a hotter liner not only draws better, it allows less creosote to condense on it. It's that thick buildup of creosote which is responsible for chimney fires in the flue, and the softwood we have here in Bend makes its fair share of creosote.

Good reasons to pay extra for the wrap, I reckoned. I talked it over with Mrs Elliott and she agreed. The best price we were able to get which included a sleeve was $200 more than the other quotes without sleeves. I called up the two companies who had bid the job sleeveless and asked them how much more it would be to add the sleeving. One raised the price by $220. But Jeff at Cascade Heating said he had a bunch of extra insulating sleeving in the shop from another job that they had overbought for, and he said he'd add that to the job at no extra charge, making them less-expensive from their nearest competition by $250. 

Guess who got the job? 

His installers arrived this morning, as promised, and in four hours had the new liner, sleeving, and top parts (rain covers, chimney seal, etc.) all installed, then left quietly without making a fuss because they were so covered with soot and creosote flakes (they found 3'' thick chunks of creosote in the chimney throat) that they wanted to proceed directly to the nearest shower.

I fired up the stove and I'm here to tell you that it sucks very well now. When the door is opened for re-fueling, there's a stiff breeze into the firebox and the fire shows no interest in exhausting smoke into the room. 

That's an improvement.

Now the question is how good a job that wood insert on the bottom floor will do keeping the upper story warm. There's a vent in the ceiling below through which warm air from the heated room can come up into the living room upstairs, and I've got some muffin fans set atop the vent upstaits to force the air upward. I have a wireless indoor/outdoor thermometer, the outdoor sender portion of which is in the lower room, and the receiver is in the upstairs. With this I can see how much warmer it is downstairs compared with upstairs and check the effect of blowing the warm air up to the upstairs room. 

All I need is a lab coat and a clipboard . . . and an attractive lab assistant named Inga, and I'll start doing some research. 

If the wood insert doesn't work as well as we'd like, then we'll be looking at gas inserts for the upstairs fireplace. But in the meantime I bought a electrically-heated throw blanket for Mrs Elliott to snuggle in. Cheaper, I figure, to heat Mrs Elliott than try to heat the whole darn house. 


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