Best heating/cooling options for new Pacific NW home?

[Mike]

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!

 

[Anthony Matonak]

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!

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

 

[Mike]

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....

 

[Pete C]

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!

Hi,

There are some very efficient split air conditioner/heat pumps that
are coming available with a COP of about 6.

It may be possible to use the heat from a ground source to keep
maintain the capacity of an air source heat pump by pumping water over
the fins.

cheers,
Pete.

 

[SueMarkP]

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!

To answer the question, we need to know a lot more. What are your choices of
utilities (electric, gas, propane) and what do they cost? Do you have a
strong preference or dislike for a certain type of heating? Spokane isn't
like western Washington or western oregon, I believe you're much colder in
winter and your humidity is typically quite low.

Since you'll need AC, an heat pump is a good choice. About the only other
variable to add is an alternate heat source for when its below about 30F
outside. If you have a gas supplemental heating system, this could cost less
(or maybe not). Will anything else in the house be gas (dryer, hot water)?
You could also go with a gas furnace, and a "swamp cooler" for AC (don't
know the issues for winterizing a swamp cooler though).

Think about planting some deciduous trees on the south and west sides of the
house (and rather distant from the house on the west side). Think about good
windows with low-e glass. There's not much point in superinsulating the
walls if you have a lot windows with a U value of .5 or more.

 

[Anthony Matonak]

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

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.

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?

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

 

[[email protected]]

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!

Net-Tamer V 1.12.0 - Registered

 

[Ken Finney]

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!

Having a house in Okanogan County, I second most of what others
have said.

1. Bias the house towards SE, but having lots of glass that you can
shade on the SW side is a good thing also. If you have glass that
you can't shade on the South and SW sides, your air conditioning
bills will kill you.

2. Go with the geothermal heat pump. Very efficient cooling and
heating in the temperate months. But, do not plan on using it in
the middle of Winter. Below about 30 F, my heat pump is very
inefficient, and the built-in backup is an electric furnace which costs
an arm and a leg. Since you probably don't have NG available,
I'd recommend a propane furnace as your primary heating, with
the woodstove as a backup.

 

[wave_man]

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!

Net-Tamer V 1.12.0 - Registered

Mike,

I live in Spokane myself and have looked into whether evaporative
cooling is suitable for our climate. My conclusion is yes.
Definitely follow the good advice regarding passive methods in this
thread as well. You may find some resistance to installing the swamp
cooler from many contractors. They are less expensive, and less
profitable to install. You may get some rationalization in the form
of scare talk regarding mold in your ducting. Disregard. Evaporative
cooling rules in hot/dry environments like ours. Are you on the
Palouse?


JF

john fisher
systems engineer
Relion Inc.

These expressions are my own, blah blah blah

 

[...D.]

2. Go with the geothermal heat pump. Very efficient cooling and
heating in the temperate months. But, do not plan on using it in
the middle of Winter. Below about 30 F, my heat pump is very
inefficient, and the built-in backup is an electric furnace which costs
an arm and a leg. Since you probably don't have NG available,
I'd recommend a propane furnace as your primary heating, with
the woodstove as a backup.

I am just now starting to look at what it might take to build an off-grid home
in central California. I am totally green. A basic question - a geothermal
heat pump - since temps hardly ever fall below freezing in the winter & I'd
need air cooling in the summer months, is then a geothermal heat pump a real
good choice for the area I speak of (90 - 100 degree heat many summer days).

Anyone - a ballpark figure of what it costs to get into one, say a 1500 sq ft
house. (??)

Thanks,


....D.

 

[wmbjk]

I am just now starting to look at what it might take to build an off-grid home
in central California. I am totally green. A basic question - a geothermal
heat pump - since temps hardly ever fall below freezing in the winter & I'd
need air cooling in the summer months, is then a geothermal heat pump a real
good choice for the area I speak of (90 - 100 degree heat many summer days).

Anyone - a ballpark figure of what it costs to get into one, say a 1500 sq ft
house. (??)

We're off-grid in AZ. 2000 sq.ft., three free-standing (no ducting)
ground-source heat pumps, about 700 Watts each, about $4k total for
the units, plus the trenching etc. We get to use them a lot in summer
to soak up the output of the many extra hours of PV production. Much
less in winter. Our hybrid power setup is fairly large, 2000W solar,
1300W wind, about $25k in components. Because of the cost of the heat
pumps and the larger system needed to run them even in a mild climate,
most off-gridders opt to burn fuel instead.

Outdoor temps are *not* a factor with ground-source heat pumps. Check
the manufacturer's data to see how ground temp will affect output.

Wayne

 

[Steve Spence]

ground source geothermal pumps work great in colder climates. -40 air temps
don't bother slinky coils 10' underground.


--
Steve Spence
Renewable energy and sustainable living
http://www.green-trust.org
Discuss vegetable oil and biodiesel
powered diesels at
http://www.veggievan.org/discuss/

 

[wmbjk]

Let's see.... 2000, 3, 700, 4000.


2000, 1300, 25000

Nope, your numbers still don't add up.

:+)

(The preceeding off-topic comments were intended for humor only.
No serious meaning should be read into them. Void were prohibited.
Contents sold by weight, not volume.)

Shush! You're going to cause somebody to write several paragraphs
about how I'm hiding the pipe sizes, the wire sizes, the circulation
pump current, blah blah blah, and that if I'd really done this stuff
then it would be on a website.... ;-)

Wayne