[Greenbuilding] Fresh air to boiler questions

Thu Jan 15 08:41:42 CST 2015

Norbert.
There is no damper of any kind. I could add one, but there isn't much room
beofre the brick chimney. Perhaps on the horizontal portion, if that is
acceptable.
However, I am still considering a new boiler. Does anyone have any input as
to my original question--what would be the ROI on a newer more efficient
direct vent boiler? I just found this link, but have no way to determine if
it is accurate.
http://www.houseneeds.com/learning-center/hydronic-boilers-learning/boilers-heat-source-costs-example
Thanks!
Ben

b e n j a m i n p r a t t

professor art+design
the university of wisconsin stout

On Thu, Jan 15, 2015 at 7:40 AM, Norbert Senf <norbert.senf at gmail.com>
wrote:

> On Wed, Jan 14, 2015 at 4:36 PM, Benjamin Pratt <
> benjamin.g.pratt at gmail.com> wrote:
>
>> Norbert, I would love to close off that 6" hole. I was told that the
>> boiler would operate less efficiently if I do that. I suppose that assumes
>> less oxygen
>>
>
> not true, common fallacy. In some jurisdictions, building code may require
> it, or it may be in "manufacturers installation instructions", so you need
> to check that.
> Only exception I can think of is a separate, sealed, furnace room. Always
> make sure you have a CO detector, since low level CO spillage is very
> common with your type of setup, outside air or not.
>
>
>> IF that is not true, I and am ready to plug up that hole! Any ideas about
>> the open flue of the boiler and the water heater? Are they less concerning?
>>
>
> Not sure, since my experience is with wood and not oil or gas. In a
> basement, you are very likely to have negative pressure, so on standby
> perhaps there is not a lot of flow from the basement into the barometric
> damper, particularly if you have an outside chimney. If you take a sheet of
> old style newsprint, it has a grain orientation to it, and in one direction
> you can tear it into parallel strips. This makes a handy flow visualization
> tool, for example low flows into open fireplaces. It might be interesting
> to check around your barometric dampers, air inlets, window drafts, etc. A
> stick of incense, or a cigarette, is good also ;-)
>
>
>> Thanks!
>> Ben
>>
>>
>>
>>
>>
>> b e n j a m i n p r a t t
>>
>> professor art+design
>> the university of wisconsin stout
>>
>> On Wed, Jan 14, 2015 at 3:04 PM, Norbert Senf <norbert.senf at gmail.com>
>> wrote:
>>
>>> The air consumption of an 80,000 BTU/hr boiler is in the range of 25 cfm
>>> while it is operating. Heating that combustion air by 50 degrees F requires
>>> about 3,000 BTU/hr, which happens no matter whether the outside air has a
>>> direct or indirect path to the burner.  Having a 6" dia permanent leak in
>>> the basement is a really inefficient way to do it. There is no good
>>> engineering reason to have that leak, unless your basement is hermetically
>>> airtight and 25 cfm would depressurize it enough to cause the boiler or
>>> water heater or (worst case) an open fireplace to backdraft. This is
>>> generally considered to be -5 Pa. Much more likely that a 250 cfm kitchen
>>> exhaust hood would do it, assuming that your basement is not sealed from
>>> the rest of the house. Clother dryers and bathroom fans also, are in the
>>> 100 cfm range.
>>>
>>> On Tue, Jan 13, 2015 at 7:43 PM, Benjamin Pratt <
>>> benjamin.g.pratt at gmail.com> wrote:
>>>
>>>> I have been sealing up and insulating the unfinished portion of my
>>>> basement, but am concerned it is a waste of time and money: There is a 6"
>>>> fresh air duct to provide proper combustion for the boiler. Also, there is
>>>> no damper on the water heater or boiler. Therefore, a lot of cold air is
>>>> continually dumped into the basement, and a lot of hot air escapes up the
>>>> chimney.
>>>>    I suppose the solution to this would be to install a new boiler, and
>>>> to install a direct vent kit on the water heater. The boiler is around 15
>>>> years old, and is 84 percent efficient. If I buy a more efficient boiler,
>>>> that is direct vented, any guess as to how much energy I will save? I
>>>> suppose its more then just the amount of natural gas I will save with a
>>>> more efficient boiler, since I would also be eliminating a huge source of
>>>> air infiltration. I would like to be able to calculate the ROI, so my wife
>>>> agrees to the purchase.
>>>> I'd appreciate any help you can provide.
>>>> Thanks,
>>>> Ben
>>>>
>>>>
>>>>
>>>> b e n j a m i n p r a t t
>>>>
>>>> professor art+design
>>>> the university of wisconsin stout
>>>>
>>>> On Tue, Jan 13, 2015 at 3:46 PM, Sacie Lambertson <
>>>> sacie.lambertson at gmail.com> wrote:
>>>>
>>>>> I'm looking for an architect in Seattle who understands energy
>>>>> efficient good building and does contemporary design work.  Welcome
>>>>> suggestions.   Best to send these off the forum, to me directly. Sacie
>>>>>
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>>>>
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>>>
>>>
>>>
>>> --
>>> Norbert Senf
>>> Masonry Stove Builders
>>> 25 Brouse Road, RR 5
>>> Shawville Québec J0X 2Y0
>>> 819.647.5092
>>> www.heatkit.com
>>>
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>>
>>
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>
>
>
> --
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Québec J0X 2Y0
> 819.647.5092
> www.heatkit.com
>
> _______________________________________________
> Greenbuilding mailing list
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>
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