geothermal sticker shock

[slapshot]

Speaking of insulation and sticker shock.....I just got a quote from a local BioBased dealer (soy based foam insulation similar to icyene), it was almost $11,000!!! Fiberglass was <$2000.

-dave

 

[Jagmandave]

Well, in SLO you can probably get away with no A/C, I didn't have it in my house in San Diego either. But here in KC where you get 100*+ days and it only gets into the high 80's at night, PLUS about the same humidity, you need A/C.

I'm also trying to be "smart" about my new house, with lots of energy efficient windows on the south side, limited exposure on the north, and I'm planning to build using ICF's, so I agree with your theory............

After reviewing all the plans we already had in place to save energy, we concluded the geothermal heating wasn't cost effective - at least in our lifetimes, so we're going with a 95% eff. forced air gas HVAC with a fresh air heat exchanger.

 

[SLOBuds]

I would not disagree with that a bit. And I suppose that I should clarify my first post by saying that I was able to achieve comfort without air conditioning, not meaning to say that everyone can achieve the same results. I am fortunate enough to live in an area which always dips to 65 degrees at night, even after day temperatures in the mid-teens.

The point I wanted to make is that auxiliary heating and cooling can be minimized through good planning and implementation of passive measures. AND that those measures are far more cost effective than buying the most energy-conserving auxiliary device available.

There are limits to how far you take this concept though. If you dropped the entire house 5 feet into the ground, you would achieve constant 65 degree temperatures. Year round. But your family would start acting like gophers!

Basements are not typical in California homes, like they are in almost every other state. Did you consider going down into the ground with your KC home? Or berming? I believe that you will find constant temperatures in the mid-60s at that depth. Some designers will then bring cool air up from the basement and through the fresh air heat exchanger. And if you combine that with a mechanism to remove hot air from the ceiling areas, it turns out pretty effective.

But I don't really know if it will make a dent on your 3 months of 100* days/80* nights.

It does suprise me a that you can't achieve passive heating. I was under the impression that winter heating is fully possible in all points of the globe. Maybe I'm wrong about that.

You made a remark about not paying back in our lifetime. The geothermal. That's my problem too. I don't mind going the extra mile for myself, and even part of the way for the next guy (might be my kids or grandkis anyway!). But I think the paybacks are so far out on some of these things that the mechanicals will break before we reach that point.

In my case with geothermal, as an example, the ground tends to shift here in California. /forums/images/graemlins/smile.gif Even if the thing has only a 30-year payback, I'm not sure that all of those holes or trenches in the ground won't be on some massive fault and therefore busted come 18 years into the payback period.

The photovoltaics is another story. With tax rebates we have a fairly short payback period. And I've designed the system so that I can add capacity when needed. In my mind, these technologies have a discrete payback period which will SHORTEN over time as the cost of energy increases.

 

[Jagmandave]

I agree with practically everything you wrote there...........
Our house will be two story, built with ICF's, and since the lot is sloped, the back and most of the two sides of the basement (or, actually, the lower level) will be underground. The front faces south, and we have lots of large windows on that side for some thermal heating in winter, and the right sized roof overhang to keep the direct sun out during the hottest part of the days, so we're doing what we can with the design. I also want to build the house for resale at some point in time, so I have to be somewhat sensitive to the market here, so no straw bale walls for me. Consequently I also won't be putting any solar water heating panels on the roof.
Using ICF's (insulated concrete forms) can yield R values between 30 and 50, depending on construction methods, so this will help too. One of the other benefits of using concrete for your walls, at least here in Tornado alley, is it's easy to construct a "storm room", and ours will have that as well.
I like the idea of solar thru photovoltaics, but our local utility does not "buy back" power or offer rebates, so the payback will be limited and slow. I actually was planning to move to SLO from San Diego, as I really like that area, but I got married. I had a home, family and career in Ca, she had the same here in KC. Guess where we're living...............sighs.........

 

[SLOBuds]

I am surprised that you still need auxiliary heating with all that you say is there. With all of those south-facing windows. Did your architect do one of those heat-load calculations on your house?

People in the early days of trying to implement passive designs felt that 'more windows are better windows.' Those people ended up shading those windows.

My day job is in Los Angeles. I'm looking forward to full-time SLO life!

 

[Ken_f]

Just got one istalled a few months back. Made a web page about it:

http://home.earthlink.net/~kjfrazi/project.html#DX

So far I like it. Used the A/C a few times and I must say it really cools the house down fast.

Still not 100% sure it was worth it yet.

Ken

 

[Westonium]

Has it shown to be a monthly energy bill saver? You don't tell us on your web page. I was really excited to do this as well, but if it is going to be 4X of the price of a regular heatpump - it doesn't sound very attractive.

 

[newcountry]

I always said I would have a geo-thermal unit when I built because it was such a great use of natural resources and energy-efficient. Then I saw the bid for my new house and did many of the same things as Jagman. High-efficiency heater and A/C cost about 1/2 to 1/3 what geo-thermal would've. I just could not justify that.

 

[heehaw]

i don't know how they would do the zones without separate units, so maybe thats what is driving the price up..around here they say about 200ft of pipe per ton, so you would only be looking at about 600 ft...3, 200ft wells...thats how they ususally do it here..but, that said, i only know one person that installed a geothermal system that hasn't had any problems..and he uses the water from his well, instead of the loops..the rest of the systems seem to be high maintenance, and short life...3 people i know had to replace their units within 8 years, so any savings they had went out the window.
i have a video on new house building, actually cowboydoc had it and has mailed it to the next person that wanted to look at it, when i get it back i can send it to you..i think it could save you some $$$
heehaw

 

[techman]

Zoning can be done with motorized ducts, along with variable speed blowers. There are a number of units on the market to zone this way, but they are not cheap.

As for the geo, a horizontal pipe system needs 400'-600' per ton. Your 200' is way too low. You can put 2 or 4 pipes in a trench. This will shorten the overall trench length, but the feet of pipe goes up. For example, 4 pipes in a trench requires about 1.25 times the pipe length of 2 pipes in a trench, due to heat flow in the ground.

paul