Best heating/cooling options for new Pacific NW home?

 We are in the final planning stages of building a new home - 2500 sf
1.5 story cape cod style home south of Spokane - trying to figure out
what to do for HVAC. Had considered Geothermal heat pump but the high
initial cost and uncertain (ie longer than what the installer clains)
payback on it has ruled it out. Air source heat pump is probably my
next choice. If I didnt have to figure for AC (we are out in the open,
no shade) I might consider some type of hydronic (boiler with
baseboard heat) but I figure we will probably need some AC in the peak
summer. Any advice? We will have a fireplace (Vermont Castings) so I
figure the fireplace would offset the inefficiency of the air source
heat pump at temps below 30 deg. What would you do? Any advice is
greatly appreciated!

  Mike wrote:

You've got a whole bunch of things mixed up together there so it's
not a simple "buy this" answer you'll get. I'm no expert in these
things (but I can play one on the internet) but I can give you
some thoughts.

First, you are planning your home now so it's a good time to plan
it to use as little HVAC as possible. This means super-size the
insulation, orient it properly for natural light, heating and
ventilation, proper overhangs on the windows and so forth. Some
insulation technologies, like spray in foam, perform much better
and are more difficult to mess up the install than older standbys
like fiberglass. The insulation is a one time cost while heating
and cooling are ongoing ones.

Next, compared to the price of the house, your heating and cooling
system is likely to be fairly inexpensive. Try to figure out the
various costs, savings and what you give up going with the different
systems. I know some people who like the under floor hydronic systems
so much they don't particularly care about the cost.

You should learn more about the fireplace before you count on it
for heating your home. Most fireplaces aren't designed as furnaces
and some will even suck the heat out of your home.

Lastly, there is nothing saying you can't have multiple forms of
heating and cooling. For instance, whole house fans can cool the
house during the night so it'll take longer to warm up in the
morning. Solar air heaters, sunspaces, attached greenhouses or
the like can provide some heat. Adding phase change materials
inside the building can give it more temperature stability. Corn
and pellet furnaces can work in conjunction with heat pumps.

Anthony

 Anthony -
When you say "super-size" the insulation, does that include making the
wall thicker, or going with a denser material?

The house is out in the open, no shade... what would be the best
orientation? Right now, we were planning on setting it at a diagnol,
with the front aimed to the SW - are there any guidelines to follow in
arriving at the best orientation?

Thanks for your thoughts....


wrote:

 Mike wrote:

Either, both, whatever works for you. You want to increase the R value
and however you go about doing that is up to you and your architect.
It's not just the wall. You likely need to consider the floor and
ceiling as well.

There are some people who build using straw bales. These are rated
around R50 and I'm told that is a fairly good amount of insulation.
Like anything else, this is a trade off. The higher the R value
the better but it also costs more and at some point adding more
insulation becomes either financially, thermally or dimensionally
impractical.


I'm sure there are but not being an architect I wouldn't have the
handbook in front of me. Generally you want the long dimension and
more windows facing South (in the Northern hemisphere) for winter
heating and the opposite for summer cooling. If you want solar PV
or heating panels on the roof they work better tilted at an angle
equal to your latitude and facing mostly south. If you wish to
use natural breezes to help cool your house then you need large
openings (windows, french doors or the like) on both sides of the
house perpendicular (at right angles to) the prevailing breeze.
If you want to avoid strong winds then you would orient your
building with it's narrowest side facing the wind and have as
few windows or openings on that wall. As you can see, a lot of
this depends on the site and some of them are contradictory so
you'll usually have to compromise. There are even some lighting
decisions that would vary from person to person. For instance,
in my case I like the bedroom and bathroom windows to face East
to catch the rising sun and to provide a modicum of warmth on
those cold winter mornings. I live in a hot climate (Los Angeles)
so I prefer something like an attached garage on the West side
to take the blasting heat of summer sunsets. In your situation,
you may choose to give up some performance in exchange for views
or to keep the style of your home.

Anthony

 

On 2004-05-31 mparkesnospam@mparkes.com said:
   >Newsgroups: alt.energy.homepower
 ...
   >The house is out in the open, no shade... what would be the best
   >orientation? Right now, we were planning on setting it at a diagnol,
   >with the front aimed to the SW -  ...
I wouldn't orient to the SW - you will be receiving fierce solar when you
need it least, when your house is already quite warm and outdoors is at its
highest temperature and experiencing maximum heating.

Solar house practice here is to bias the south wall toward the east, to
increase the early-morning solar input.  The sun's path is twisted about 12
deg. eastward, so you might consider more than that.  (That's true
direction, not compass, which, I think, is _way_ off where you are.)  That
same eastward bias puts your south wall in shadow later in the day, for much
of the year.

South roof overhang will give seasonal shading.

We minimize west window area!


Tom Willmon
Mountainair, (mid) New Mexico, USA

Read the manual.  Now there's a radical concept!

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