<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Tahoma
}
--></style></head>
<body class='hmmessage'><div dir='ltr'>
<P style="MARGIN-BOTTOM: 0in">On Sat. 24 Dec. Eli outlined both his current wood heating practices and </P>
<P style="MARGIN-BOTTOM: 0in">additionally his concepts for improving the heating efficiency of his dwelling: </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">Considering the air speed and volume, carbon soot, and potentially embers, </P>
<P style="MARGIN-BOTTOM: 0in">isn't using a Shop Vac on the pit of a recently used chimney pushing the line </P>
<P style="MARGIN-BOTTOM: 0in">a tad too far? Hopefully the list readership recognizes just how dangerous </P>
<P style="MARGIN-BOTTOM: 0in">this can be. </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">I tend to agree with Rob T 's suggestions regarding heating improvements </P>
<P style="MARGIN-BOTTOM: 0in">(I'm another moose-burgher, but from a not quite so chilly part of Eastern Ontario). </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">Regarding exterior wood fired boilers, it's my understanding that the fires tend </P>
<P style="MARGIN-BOTTOM: 0in">to run cool due to the water jacket and are thus prone to inefficiency and creosote </P>
<P style="MARGIN-BOTTOM: 0in">production. </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">I would look closely at the losses occurring in the long lines out to the boiler, </P>
<P style="MARGIN-BOTTOM: 0in">as I suspect they would become quite significant. To prevent freeze-up, units </P>
<P style="MARGIN-BOTTOM: 0in">around here tend to require expensive propylene glycol and thus great quantities </P>
<P style="MARGIN-BOTTOM: 0in">for the interior tank or suffer the losses of an extra heat exchanger. I would think </P>
<P style="MARGIN-BOTTOM: 0in">using cheaper ethyl glycol is risking fatal poisoning or poisoning of your </P>
<P style="MARGIN-BOTTOM: 0in">aquifer. The glycol needs to be pumped, thus an additional electrical cost and </P>
<P style="MARGIN-BOTTOM: 0in">eventual failure site, and really needs a fail-safe power source, yet another cost </P>
<P style="MARGIN-BOTTOM: 0in">and source of failures. </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">The thermal losses from a large thermal tank need to be accurately determined </P>
<P style="MARGIN-BOTTOM: 0in">(my solar DHWT losses surprised me) and hopefully directed to interior winter </P>
<P style="MARGIN-BOTTOM: 0in">heating needs. Even if non-pressurized, the forces on tall tanks must be managed </P>
<P style="MARGIN-BOTTOM: 0in">structurally and may well shorten the lifespan of common inexpensive materials. </P>
<P style="MARGIN-BOTTOM: 0in">Is your 'significant other' prepared to deal with 10 tons of water throughout the </P>
<P style="MARGIN-BOTTOM: 0in">house? Mine drew the line at 120 gal. :) </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">When planning our renovation we examined various forms of hydronic heating in </P>
<P style="MARGIN-BOTTOM: 0in">detail - fully expecting that it would be optimal. Such was not the case. However, </P>
<P style="MARGIN-BOTTOM: 0in">from my investigation of interior radiator options, yes, the output is rather linear </P>
<P style="MARGIN-BOTTOM: 0in">wrt inlet temperature in the normal 160 to 190F range, but does tend to significantly </P>
<P style="MARGIN-BOTTOM: 0in">decrease below 140F. At low temperatures, it's difficult to beat antique vertical </P>
<P style="MARGIN-BOTTOM: 0in">tube cast iron radiators. At very low temperatures (80-100F) I've been told to de-rate </P>
<P style="MARGIN-BOTTOM: 0in">cast iron tubes linearly, then divide by a factor of 2 or 3! The heat will be delightful, </P>
<P style="MARGIN-BOTTOM: 0in">but the cost of so many radiators will kill you! In my case, I even examined runs </P>
<P style="MARGIN-BOTTOM: 0in">through old cast iron radiators prior to PEX in a poured slab lift to try to improve </P>
<P style="MARGIN-BOTTOM: 0in">the match with condensing boilers it wasn't cost-effective either. </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">I really agree that the initial target is to reduce the heat load dramatically - preferably </P>
<P style="MARGIN-BOTTOM: 0in">in a well planned/phased manner concentrating on benefit-cost payback. (With great </P>
<P style="MARGIN-BOTTOM: 0in">effort, we were able to get down to a net heat load of about 21,000 Btu/hr at -5.8F for </P>
<P style="MARGIN-BOTTOM: 0in">a forty-plus year old 3130 sq ft dwelling). We really liked Amory Lovins idea of </P>
<P style="MARGIN-BOTTOM: 0in">selecting design and materials such that they provide multiple beneficial uses thus </P>
<P style="MARGIN-BOTTOM: 0in">providing a much greater benefit for the cost involved. </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">Once the heat load is minimized, I would suggest examining renewables, such as </P>
<P style="MARGIN-BOTTOM: 0in">taking advantage of passive/active solar to the extent feasible and selecting a reliable </P>
<P style="MARGIN-BOTTOM: 0in">and cost-effective means of heat storage, perhaps solid mass. In calculating an </P>
<P style="MARGIN-BOTTOM: 0in">appropriate amount of thermal mass, I would suggest trying to keep the typical daily </P>
<P style="MARGIN-BOTTOM: 0in">'deltaT' within bounds acceptable to prospective purchasers of your dwelling. A </P>
<P style="MARGIN-BOTTOM: 0in">slightly larger swing might be acceptable for high solar days as at least it is seen as </P>
<P style="MARGIN-BOTTOM: 0in">'putting up with the inconvenience of free energy'. With solar, recoveries and internal </P>
<P style="MARGIN-BOTTOM: 0in">gains, purchased heat can be reduced to 20% of the total annual heat load (perhaps </P>
<P style="MARGIN-BOTTOM: 0in">less depending upon the situation and climate). </P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">However, beware, solar can be a very 'leveraged' investment. Around here, it typically </P>
<P style="MARGIN-BOTTOM: 0in">resembles a stock market equity investment in that while the pricing of markets on </P>
<P style="MARGIN-BOTTOM: 0in">average tends to be a reasonable reflection of value, markets can and do act irrationally </P>
<P style="MARGIN-BOTTOM: 0in">far longer than one can remain solvent!. In other words, unless one is very lucky with </P>
<P style="MARGIN-BOTTOM: 0in">having a very stable and predictable local climate, weeks and months can go by with </P>
<P style="MARGIN-BOTTOM: 0in">essentially no solar productivity, so one still must provide alternative heat sources </P>
<P style="MARGIN-BOTTOM: 0in">hopefully with a measure of redundancy for security. - My 2 cents :)</P>
<P style="MARGIN-BOTTOM: 0in"><BR></P>
<P style="MARGIN-BOTTOM: 0in">best wishes</P>
<P style="MARGIN-BOTTOM: 0in">Gord Scale</P>
<P style="MARGIN-BOTTOM: 0in"></P> </div></body>
</html>