[Greenbuilding] Radiant heat boiler

Wed Feb 7 20:25:03 CST 2007

learn to fire the client-- works for rg vanderweil and marc rosenbaum

you ask for advice and then reject it with the same old tired arguments 
(too many redwoods, but in the future when they get logged, we'll consider 
solar "in the  future") wow no solar for two futures just like you.

sorry to be blunt , but get some backbone.

so the decison is to buy an even more expensive unecessary tank and  not use 
it.  great

sorry to be blunt, but you asked.

the future is now

----- Original Message ----- 
From: "David Seth Melchert" <dmelchert at earthlink.net>
To: "Greenbuilder list" <greenbuilding at listserv.repp.org>
Sent: Wednesday, February 07, 2007 5:07 PM
Subject: Re: [Greenbuilding] Radiant heat boiler

> Thank you to all who offered such a well-considered response to my query
> yesterday.
>
> A few clarifications:
>
> The home owner already nixed solar hot water panels - it was my first
> suggestion a year ago when we first started planning. Most of the house
> is shaded by a grove of redwoods.
>
> I mis-stated the BTU's of the Baxi. Its input is 126K BTU.
>
> GFX/Power Pipe is not really a possibility due to a whole number of
> logistical/engineering reasons I won't elaborate here.
>
> Many of you suggested I help the owners change their habits. This is a
> tricky issue - those of us on this list are quite enthusiastic about
> changing our behavior, but many (I would venture most) Americans are
> more convenience and results driven (didn't Amory Lovins state,
> "Americans don't care if their power comes from nuclear or solar, they
> just want cold beer and hot showers").
>
> The Baxi 310 is 85% efficient, but the Baxi  HT 330 is a condensing unit
> and runs in the mid 90's I believe.
>
> Yes, George, the floors are to be well - insulated for radiant heat. The
> remodeled house design is carefully crafted for a whole number
> Architectural characteristics. Hot air duct pathways prove challenging
> in places where feeder pipes for the radiant are easy to distribute. And
> they chose the radiant largely for the comfort they experience with it.
>
> The homeowner is not likely to try a new boiler system that not even the
> employees at HSC have heard of. Who knows how they hold up, how well the
> company provides service, etc. But I do look forward to seeing how the
> Phoenix Combi does over time.
>
> One of the first suggestions posted was to have an indirect tank for DHW
> that is heated by the Baxi. This is probably what we will do - replace
> the 21 gallon Baxi modula with a well-insulated 80 gallon tank. It
> obviates the considerable cost of a secondary system. This will also
> provide future capacity for solar panel feed in the future.
>
> I admire the considerable expertise represented by this group. Thank you
> for chiming in.
>
> Seth Melchert
> Oakland CA
>
> David Seth Melchert wrote:
>> We have started a large residential remodel in Orinda, CA. The 2,800 sf
>> house will be heated with radiant floor heat. We were planning to use a
>> Baxi Luna 330 instant heater for combined radiant and domestic hot
>> water. I really love the Baxi Luna for its compact design and simplicity
>> of installation, not to mention its general high efficiency.
>>
>> However we are concerned about its capacity to serve the demands of a 3
>> bath house. The homeowner consulted with a supplier who suggested that 5
>> gpm, delta 70 degrees is the minimum required, more than the 144,000
>> BTU's the Baxi Luna provides. Baxi has a new Modula supplemental tank
>> that holds 21 gallons and serves as a kind of buffer for temporary high
>> demands. My homeowner is concerned this will not cut it. They are edging
>> towards having separate heat sources, such as a Noritz or an efficient
>> large tank for DHW.
>>
>> Here are my questions: how many gpm should we figure for hot water needs
>> at any one time, and how often might a family of four run into
>> insufficient hot water using the Baxi? Would you agree that providing
>> separate heat sources for radiant and DHW would be the best path?
>>
>> Thanks
>>
>> Seth Melchert
>> Oakland CA
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