SIPs, Radiant, Geothermal, & High Veleocity AC ?

ncdesigner

Found this site through some other sites I frequent concerning home building, etc. Hadn't had too much luck there so thought I would give this forum a shot.
Planning on building a 2,800 sf home near Charlotte, NC. Home will be two story with enclosed attic. All ext. walls and roof will be SIPs. Here are my questions:
SIPs - Contemplating using slab or crawl-space. If I use SIP walls for the crawlspace do I need to vent that area, and if so, doesn't that defeat the idea of using SIPs to create a tight envelope? I have also read into having a conditioned crawl space. Anyone have any pros and cons about that?
Radiant heat - I like this a lot, but not totally sold on it yet. I don't know if it would suit my location. I do know a few people who have it around here and they like it a lot. Not sure about which system to go with. I will likely only use at entire first floor and master bath on second. First floor will be 100% hardwood and/or tile. I definitely want to nail hardwood, no gluing. I feel like the engineered wood is stable enough to make this work. Other than putting sheathing on concrete, I guess it would make the most sense to build over a crawl space? Any other ideas? Very confused about the pros and cons on this one and the possible extra costs.
Geothermal Heat Pump - just came across this technology and it sounds great. Is it possible to install the horizontal loops under a driveway? If not, I would have to put in wells. Also like the idea of using this for hot water and hooking up to radiant heating. Can these units be installed in my conditioned attic?
Last thing is high velocity AC. I haven't found a whole lot of information on this yet, but it seems to be better that "standard" forced air ac? Again, anyone have any experience?
I know that's a lot of stuff, but those are all kind of linked together. Really trying to figure out the pros and cons of my foundation options given what I would like to do. Thanks for all of your help. Also, any suggestions other than those I have come up with are very welcomed.

Big Ed

Options

Radiant heat is the best form of heating system to give you highest comfort level. Hydronic is always the better choice.

High V AC is a great system if install correctly...And in some homes, Hi V is the only option .I perfer the Hi V over a low v .Its a nicer unit to install, mix the air space well,looks neater. The cost of the system is higher but it may be worth for the house you are building..

There are a lot of designers on this site that would help you more.. Good luck

Larry Weingarten

sips

Hello: If you're building a sips house over a crawl space, why not use Insulated Concrete Forms (ICFs) for the foundation wall and use sips for your floor as well? Or, put your sips house on a slab that has substantial rigid foam underneath it.

Research has shown that vented crawlspaces are usually wetter than unvented. Look up "Energy Design Update".

The trick with sips is to plan carefully where you're going to run plumbing and electrical. That's my two cents ;~)

Yours, Larry

Kevin_in_Denver

SIP house in NC

I've been living in my new SIP house for a year now. It has simple passive solar features such as south facing windows, and 2" concrete floors on two levels. In one year I've spent $80 on nat. gas for space heating, for about 6000 heating degree days.

The lesson for me was: minimize your first cost on the heating system if you're in a warm, sunny climate. A few electric heaters in the right spots will save at least $10k vs. a complete in-floor hydronic gas boiler or heat pump system.

If I had done this, my yearly space heat bill would be more like $200. In the long term, electric cost will be more stable than natural gas, because electricity can come from renewables like wind and solar.

A perimeter insulated slab on grade helps increase your thermal mass. 1" of XPS under the slab is probably not required because the cooling effect of the slab helps you more in the cooling season than it hurts in heating season.
The radiant heat in my basement slab has never, ever, come on even when it was -5F outside. (Of course, the XPS is required if you plan to put heat in the slab.) Window shades on the south windows for Sept and Oct. are needed to prevent overheating.

Unvented, conditioned, insulated crawlspace (and attic for that matter) is much better than the conventional methods.

For a great discussion of passive solar design, check out
OurCoolHouse.com
Keep in mind he went with a heat pump because the climate is cold and cloudy in winter, hot and humid in summer. Concrete floors and south facing windows don't really add to the cost of the house.

SIPs and Solar, yeah, that's the ticket!

Kevin_in_Denver

Check also sipweb.com for more info.

Brent_2

geo

You can put horizontal loops under a driveway but it sounds like if you are asking this your lot is smaller. You will have to figure out your cooling load and then you can determine how much horizontal trenching is needed. Vertical wells may make more sense. Horizontal loops need a fair amount of area and then you are locked in to never use that space for a pool or anything else you dream up. You could put the geo equipment in the attic. You would need to run the water loop up to the attic. Since your area is cooling dominated it will be great that you will get free domestic hot water all summer.
You can make heating hot water with geothermal but you will need a separate water to water heat pump. I'm not sure it would make sense in Charlotte.
It is unusual for hi velocity to be used in new construction. It is done though. Hi velocity systems cost more and in new construction you can usually find space to run standard ductwork.

Brent

J Matthers_2

Sips Geo

Sips, Geo IFR and High V is exactly what I used for my new house on Long Island.

You can find lots on Sip info on www.sipweb.com as someone else pointed out. The one mistake I made was putting a convictional roof on. I have since had it sprayed. You could put in a closed conditioned crawl space, a vented one and use SIP floors over it or, for less cost, a slab on grade insulated below.

Geo and IFR in a well insulated tight house is a marriage made in heaven. The low temp demands of a well designed IFR system is perfect for the low 110* to 120* temps you will get from the geo. There are several ways to do Geothermal or ground source heat pumps, closed loop, open loop or direct exchange. Although an open loop water to water is probably the most efficient, your water source needs to be excellent and you ground conditions on the injection well side need to be good to prevent problems. Closed loop is more expensive and soil conditions surrounding the wells is important for good exchange. Direct exchange is an interesting idea where the refrigerant coil is buried in the earth eliminating a step in the exchange process. Be sure you have amble space to spread out coils.

In your climate, you cooling load is likely greater than your heating load. The Geo system is far more efficient at cooling than a conventional air exchange heat pump or compressor.

The upside of the HV system is the latent heat removal. It is about 30% greater then a conventional ducted system. I can leave my thermostat on 78* during the cooling season and be very comfortable. The HV system can also provide heat using the Geo with an electric backup if you need it on unusually cold nights.

Good Luck