[Greenbuilding] Passive Solar and HVR/ERV systems

Sat Feb 24 15:04:55 CST 2007

Thanks for the info. One thing, both our green builders have said that
forced air is the cheapest way to heat, and half the cost of radiant floor
heating--it's odd that you find it less expensive... Cheers!

Mary Bull, Co-director
Greenwood Earth Alliance, Save the Redwoods - Boycott the Gap Campaign
252 Frederick, San Francisco, CA 94117 http://www.gapsucks.org
Chalice Farm and Sustainable Living Center, 748 Montgomery Rd, Sebastopol CA
95472
415-731-7924 - 415-509-1188 chalicenew at earthlink.net

----- Original Message ----- 
From: "Ward Edwards" <ward at buildgreen.ca>
To: "Ian Albinson" <ialbinson at moonbase9.com>
Cc: <greenbuilding at listserv.repp.org>
Sent: Saturday, February 24, 2007 8:26 AM
Subject: Re: [Greenbuilding] Passive Solar and HVR/ERV systems

> Hi All,
>
> I have been away from this list for quite a while, but I have to jump in
> on this discussion.
>
> I have built a super insulated, passive solar house that is a two story
> walkout (the south side is two stories, the north is one story).  We are
> using radiant heat on the lower floor (3.5" concrete over R15 foam) and
> a wood stove.  We are also using a propane fired tankless hot water
> heater for heat and hot water.  We have the thermostat to kick in at
> 20.3C and shuts off at 20.8C.  In the winter when the sun is shining,
> the temperature will climb to about 24C (a bit warm but still
> comfortable)  and the house will stay warm until about 10pm (the sun
> goes down at about 4-5pm) and the infloor heat will kick in and run for
> about 3 hours (takes a long time for to heat up all that mass) and will
> stay warm until the next morning.  When the radiant heat is on, it will
> generally overshoot the setpoint of the thermostat by about half a
> degree, due to the time it takes for the heat to move through the
> thermal mass. If the day is cloudy, the heat will kick in mid morning
> and run for about 3 hours again.  The plan for this year or next is to
> add an active solar component to add more heat to the slab in the areas
> of the house not directly exposed to the sun.  So far we are using 425
> gal of propane a year (heat, hot water and cooking) and about 1/2 a cord
> of wood.  We also have a Lifebreath HRV which has it's own ducting
> system to control the humidity.  In the summer the house rarely gets
> above 25C.
>
> The radiant flooring was inexpensive to put in ($600 for Kitec, $800 for
> manifolds, control and pump) and we had to have the tankless hot water
> anyway.  We have hot water radiators upstairs and this added about
> another $900, so it is still less than a furnace and ducting.  Since we
> don't need A/C the lack of ducting is not an issue.
>
> The floor is warm to bare feet when the sun is shining on it (just
> checked with an infrared thermometer and the temp is 80F (26C)) .  The
> only problems I have had with the radiant floor heat is that if I use
> the woodstove a lot to conserve propane, the floors in the back of the
> house tend to get very cool (about 15C) as they have no solar gain and
> are away from the woodstove.  We have had no problems with overheating
> combining the radiant heating with passive solar, as the sun can get the
> floors above the setpoint of the radiant heating and thus absorb the
> extra heat.  We almost always wear slippers, mostly due to the hardness
> of the floor, but the house is almost always comfortable.  If you have
> any further questions feel free to ask
>
> Ward Edwards
> Ward at buildgreen.ca
> Ian Albinson wrote:
> > Hello,
> >
> > Does anyone here have experience with passive heating and cooling?
> >
> > I'm planning to build a super-insulated 2000 sq.ft house in Vermont,
> > and would like to find out if a passive system will be enough to keep
> > the indoor temp pleasant throughout the year.
> >
> > The house will be south facing on the site, and use a large bank of
> > triple pane low-e windows for solar collection. I'm also looking into
> > the
> > possibility of a solar hot water system.
> >
> > Thank you,
> > Ian
> >
> > _______________________________________________
> > Greenbuilding email list
> > List info:
http://listserv.repp.org/mailman/listinfo/greenbuilding_listserv.repp.org
> > List email: Greenbuilding at listserv.repp.org
> > Managed by BuildingGreen, Inc. http://www.buildinggreen.com
> >       publisher of Environmental Building News and GreenSpec(r)
> > Hosted and archived by REPP / CREST http://www.crest.org
> >
> >
>
>
> _______________________________________________
> Greenbuilding email list
> List info:
http://listserv.repp.org/mailman/listinfo/greenbuilding_listserv.repp.org
> List email: Greenbuilding at listserv.repp.org
> Managed by BuildingGreen, Inc. http://www.buildinggreen.com
>       publisher of Environmental Building News and GreenSpec(r)
> Hosted and archived by REPP / CREST http://www.crest.org
>