[Greenbuilding] [BULK] Re: Fw: Trying to maximize passive solar gain without investing too much....

[Lawrence Lile]

On Apr 18, 2007, at 15:56, Christa Carpenter wrote:

> Can you have too much thermal mass?  I have a book that gives minimum
> numbers corresponding to the area of southfacing glazing, but they
> don't mention whether or not you can have too much.

>Corwyn said:No. 

That's a good short answer, Corwyn.  I'd add that, in a conventionally constructed home, you probably won't have too much mass.  At some point, a lot of mass leads to slow heat-up, and if the building ever does get cold, you end up spending $$$ to get it back up to temp. Double sheetrock is a good idea and is not nearly enough mass to have this negative effect, that's my guess.  

> Do you think it is worth it to do this for a conventional house that
> we will try to sell to conventional people in a few years time or am I
> banging my head against a wall unnecessarily?

Corwyn Said:Everything you can do to make a conventional house better should be
done, in my opinion.  

Go beyond the standards you cite for insulation, unless they are really extreme.  Most building standards are a compromise.  



> Do you have any suggestions for how to heat this house in addition to
> the passive solar gain?  We get rebates here for using forced air, but
> I am loath to use furnace oil again.

>Corwyn wrote: Forced air is not my favorite heat distribution method, but it is not
completely unreasonable (with all ducts inside the heating envelope). 
What are your other options for fuel?  You ought to be able to have
forced air with a gas furnace if you want.  Talk with a local heating
contractor should get a list of all your options.

Radiant floor heat is very popular now, and I am starting to become aware of it's limitations.  A lot of heat can get sucked down into the ground, or wasted due to inefficient controls.  Insulate your slab really well.  There are sites that recommend only perimeter insulation on slabs, to add tons of mass inside the envelope. I am starting to realize this isn't always the best approach.  

Ducts inside the heating envelope can't be stressed enough.  If you are North of Air Conditioning country, then you don't really need forced air, and can rely on other methods.


> Is there any other advice you might give?

>Corwyn Wrote: If you must have a garage, it should go on the west side, all things
being equal.

Yes, shade the West and open up to the East.  East light in a kitchen adds a lot to a home in heat energy when you need a boost, daylight when you are waking up, and cheeriness when you are tired of winter.  

--Lawrence