[Greenbuilding] mini split? Always?

[jfstraube]

A wood stove has far fewer problems with distribution, but more problems with comfort.
Wood stoves are very high temperature heat sources: surface temperatures of 300 F and higher are not uncommon.  This generates a powerful plume of rising hot air that moves air around rather aggressively in all connected spaces.  Like mini-splits, the heat does not get to rooms with closed doors, but at least wood stoves mix and churn the air in open areas.
That said, they tend to have comfort problems due to overheating, especially radiant asymmetry. Interestingly, people dont mind getting baked in winter as much as they mind being a little cold in a back bedroom.
Pellet stoves and zero-clearance fireplaces increasingly include some interconnection to an air handler to overcome some of the distribution problem, and both have heat shields to convert more of the radiant heat into convective air heating.  Pellet stoves also respect "modern lifestyles" of people not being home for 10 hours a day while they work, not wanting to get up at night to refuel, etc.

On 2010-10-12, at 12:44 PM, Reuben Deumling wrote:

> 
> Thanks, John.
> 
> On Tue, Oct 12, 2010 at 9:37 AM, John Straube <jfstraube at gmail.com> wrote:
> Climate?
> Ah yes. This is in Portland, OR. Around 4,000 HDD. Few hours or days below 10F. Most years I'd say none.  The condo in question is quite compact but one complaint has been that with an open stairway in the middle all the heat goes up quickly. The status/presence/absence of insulation in walls and ceiling and under the floor are unknown but definitely something I'd like to investigate a bit more. 
> The huge problem with mini-splits is there lack of distribution. How to spread the heat and cool around without causing discomfort in far corners of buildings.
> 
> Sort of like a wood stove?
>  
> Second issue is capacity: most are limited to 24-36K.
> Systems with air handlers and higher capacity are available but their cost tends to skyrocket and the performance drops a lot.
> If many cases, a standard US brand air source heat pump is not a bad choice: a Carrier, Goodman or Trane SEER16 heat pump with an ECM air handler can be a great swap out for electric furnaces in homes with modest heating demand in climates without many hours below around 10 F.
> 
> An air source heat pump is going to sit outside, yes? Given that the ducting radiates from a closet in the center of the unit would one expect some new ducting to, say, run in a crawlspace to said closet before tying into the existing system? 
> 
> 
> On 2010-10-12, at 12:32 PM, Reuben Deumling wrote:
> 
> > I'm helping some folks replace their forced air electrical furnace (1970s condo, two level, 1,200 square feet) and from paying peripheral attention to electrical heating discussions here I understand that a mini-split system is the way to go if energy efficiency/low energy consumption per HDD is the top priority and wood and gas are not options.
> >
> > I normally only work with wood and natural gas heating systems, so this is new to me. Any introductory tips? Advanced recommendations? Obvious mistakes to avoid?
> >
> > Thanks so much.
> >
> > Reuben Deumling
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