New Home/system desing

[tclynx]

Hi I'm new. I've been reading up on the site but I doubt I can read enough to catch up. I uderstand the site rules and am not asking for step by step anything, nor am I asking for any specific prices. Please answer in generalities about such things so as not to upset anybody. I am planning to be a Home Owner (planning to be an owner/builder actually). Probably about to open a big can of worms, hopefully some really cool ones pop out of the discussion.

Anyway, I want an energy efficient, safe and healty home but on a modest budget. Phase one of construction would be 1700 sf give or take a couple of hundred sf. Hopefully in the near future we will be able to expand and add perhaps 1000 sf of living space. Starting off with two people and planning a family of 4+ any extras.

The building technique will be insulated thinshell concrete. Most likely of the airformed structurally engineered type. To explain more throughly, Extermal layer of the home will be a durrable vapor barrier and then 3 inches of Polyurethain foam. The interior will be the 2-4 inches of steel reinforced concrete, applied as shotcrete. Therefore (provided we make good choices in windows and doors) it will be a very well sealed, incredibly insulated structure with a sizeable thermal battery on the inside.

All on it's own this type of construction is supposed to be very efficient on heating and cooling (though careful though must be paid to ventalation because it is very well sealed).

We are interested in in floor radiant heat (for what little heating we will need).

We will be doing a fair bit of digging on the site (just under one acre, fairly level) to put in septic and also some trenching for other items like bamboo root barriers. Only noting this in case we could simply dig a little deeper to put in geothermal loops under. Primarily sandy soil.

The site has some good trees along the south and west side for some protection from the sun and I plan some sizeable overhangs for any south faceing windows and perhaps a wrap around porch.

Finally, perhaps most pertinent to this discussion, the location is in inland Central FL. Primarily a cooling climate with high humidity.

My Questions,
What would you recomend for this type of situation?
What about geoexchange in Central FL? (especially if we are digging anyway)
Was planning on Solar hot water with on demand backup.
I did see a web site for a solar powered Chiller, anyone have any experience with this yet?

Thanks for any input,

[dan sw fl]

Originally posted by tclynx
Anyway, I want an energy efficient, safe and healty home but on a modest budget. Phase one of construction would be 1700 SF give or take a couple of hundred sf.

The building technique will be insulated thinshell concrete.

Only noting this in case we could simply dig a little deeper to put in geothermal loops under. Primarily sandy soil.

Finally, perhaps most pertinent to this discussion, the location is in inland Central FL. Primarily a cooling climate with high humidity.

My Questions,
What would you recomend for this type of situation?

Was planning on Solar hot water with on demand backup.


Your A/C unit may only be 2 or 2.5-Tons depending on house orientation, ceiling insulation, tightness and amount of windows/ SHGC and u-value. Perform a detailed load analysis per ACCA Manual J to determine actual needs.

I would investigate Ground Source Heat pump with closed loop.

http://www.geoexchange.org/about/how.htm

http://www.waterfurnace.com/content.aspx?section=residential&page=rez

Payback might be > ~10 years based on current electric rates. However, that payback period will obviously be shortened with an initial 17% rate increase coming in a few months.

[cem-bsee]

read at BUILDINGSCIENCE.com!! including the study about wind driven rain 2004. and, location of the vapor barrier!

you have quoted the wrong location for barrier --

elevate house on lot, insulate slab perimeter --

[dan sw fl]

Originally posted by cem-bsee
read at BUILDINGSCIENCE.com!!

And this is in reply to WHAT?

[teddy bear]

Originally posted by tclynx
Hi I'm new
The building technique will be insulated thinshell concrete. Most likely of the airformed structurally engineered type. To explain more throughly, Extermal layer of the home will be a durrable vapor barrier and then 3 inches of Polyurethain foam. The interior will be the 2-4 inches of steel reinforced concrete, applied as shotcrete. Therefore (provided we make good choices in windows and doors) it will be a very well sealed, incredibly insulated structure with a sizeable thermal battery on the inside.

We are interested in in floor radiant heat (for what little heating we will need).

We will be doing a fair bit of digging on the site (just under one acre, fairly level) to put in septic and also some trenching for other items like bamboo root barriers. Only noting this in case we could simply dig a little deeper to put in geothermal loops under. Primarily sandy soil.

Finally, perhaps most pertinent to this discussion, the location is in inland Central FL. Primarily a cooling climate with high humidity.

My Questions,
What would you recomend for this type of situation?
What about geoexchange in Central FL? (especially if we are digging anyway)
Was planning on Solar hot water with on demand backup.
I did see a web site for a solar powered Chiller, anyone have any experience with this yet?

Your vapor barrier is on the outside? Good. Your home will heat/cool with minimum input, therefore will not save enough to pay interest on extra investment, forget geothermal or infloor heat. This home will heat on the light bulbs. Focus on fresh air ventilation with air filtration/dehumidification like Ultra-Aire APD connected to a VS fan, Merv 11 filter, 13 SEER HP. A clean fresh air change every 4 hours when occuppied purges indoor polutants and maintains oxygen. Maintaining during <50%RH indoor relative humidity during all weather conditions prevents mold/dustmites growth from the exterior moisture barrier to deepest interiors of the home. TB

[wyounger]

As much as I like the idea of geothermal heat pumps, I don't see that as ideal in this case- given a modest budget. Also from what I've read you can't do a horizontal loop over or under a septic field, so you may either have to dig somewhere else or go with vertical loops. And after you build a house and a suitable septic system on that acre, there won't be a somewhere else for a horizontal loop anyway, unless leach fields just take less space in Florida than they do in Georgia.

As for radiant; it's super-nice stuff, but we're talking about a super-efficient house in Florida. There's a lot of extra cost associated with doing radiant, you're going to be spending that for a little extra comfort on the few days of the year that you use heat at all.

You're already building a super-efficient structure (SIP or ICF) in a cooling-dominated climate, and you're in an area where utilities are not particularly expensive. For my real money (not wish list money) I would just get a nice air-source heat pump. With the savings, you can afford better windows, insulation, water heating, pigmented roof, dehumidifier, etc. (Incidentally you're in a great climate for a heat pump water heater; it's not "free" like solar but it produces "free" cooling and dehumidification while it produces the hot water.)

I won't deny that the geothermal heat pump will be cheaper to run (and with a desuperheater, there may be little need for a solar water heater), but in an application that's going to be very energy efficient to start with, combined with what are reasonable utility rates (even after the 17%), payback is going to be slow. If the house were going to be bigger (maybe at 2700 sq ft to start), less efficient in its construction, in a climate with more heating demand, or just with enough lot space for a horizontal loop, then I can see a geothermal HP paying back faster on utilities. Also, since you absolutely should not overbuild your HVAC up front to try to accomodate some future addition, the need for loops leave you with a quandry- are you going to pay up front to put in a second loop now to accomodate a second geothermal HP that may not be installed for years? Or wait and drill in a vertical loop for that one? Or..?

On the other hand, if you don't mind spending extra for the environmental friendliness of geothermal, go for it. If you do manage to pull off a geothermal HP, make sure to get the desuperheater option, and provide it with a big storage tank that it heats alone so you maximize its water heating potential; any backup water heating should downstream, either in second tank or in a tankless unit. Otherwise you cripple the desuperheater by making it work on water that's already been heated by the backup heat source. With a desuperheater, again, you will have enough free hot water production that there will be little reason to have the solar water heater.

One other suggestion- from a guy who is having problems with his clothes dryer depressurizing a house that isn't nearly as tight as the one you're building- consider putting the laundry room outside the main building envelope (maybe the garage or an unconditioned mud room/laundry room combo?). Yes, you may have an ERV, but why let the clothes dryer be the dominant consumer of make-up air? Even with an ERV there is a cost associated with bringing in all that air just so you can throw it out again.

If I were in your shoes, and thinking about a modest up-front budget but still building with future expansion on my mind, here's the direction I'd head in-

-heat pump water heater ("HPWH", separate from the storage tank, such as the Nyle unit, rather than the integral type) inside the envelope (but away from the bedrooms); that heats an unpowered electric tank-style water heater, and that tank acts as the supply for a powered electric tank unit that will rarely ever draw any power (it serves as boost heat during big demand spikes and as backup in case the HP conks out). This is a bulky setup, yes, but the idea here is to build out the water heating capacity for the addition up front. Note that none of these items are very expensive, and you get some redundancy in case one component fails. For contrast: I would be afraid to rely on a tankless water heater without any backup; where are you going to get parts, a replacement unit on short notice when you have no hot water? And where are you going to find a qualified technician to repair it right away while you aren't showering? With some redundancy in the system, especially something simple and common like a regular electric water heater, you are not likely to do without for long.

-nice air source heat pump, sized absolutely as small as possible given the load calc, the thermal mass, and the fact that you already get a lot of free cooling and dehumidification from the heat pump water heater; ductwork and equipment go inside the conditioned space (though that could easily be a sealed/conditioned attic with the deck foamed); size for only what you're building out now- the addition will get a second unit when the time comes. Two speed is an open question. I'd leave room for a central dehumidifier just in case, but I doubt you'll ever need one so long as you keep using hot water from the HPWH. Note that the HPWH dumps the waste heat into your hot water, where it's useful; a central dehumidifier dumps its waste heat into the house, and in Florida that just means you're going to have to use AC to get rid of that waste heat.

-ERV, but ask yourself critical questions about just how much ventilation is really necessary and where- such as the issue with the clothes dryer- so you don't run it more than is really necessary. Don't go overboard with the kitchen exhaust fan, despite the current rage for commercial equipment. Simple 60-minute mechanical timers ($15 each!) are great instead of regular light switches for controlling bathroom exhaust fans, I might add, since the fan needs to run for awhile, but not all day, after you've finished your shower and left the bathroom.

-try to anticipate possible future infrastructure needs so that adding/upgrading/changing something in the future doesn't require major surgery to run the new cable/pipe/etc. Examples- pull an extra cable to the air handler in case you do turn out to need the central dehumidifier. Oversize the gas line so that if somebody wants to put in a big tankless gas water heater down the road in place of a gas storage water heater, the existing pipe will be sufficient.

-since we've long since learned that you can never anticipate far enough in advance what the next paradigm in data/video/audio signaling may be, put some conduits in strategic places, even if they start out empty, so it's easy to add/change future video/data/etc wiring without tearing drywall apart and/or running wires exposed on the outside of the house (cough cable company, cough cough). It may seem silly now, but somebody will thank you for it in 20 years. This kind of thing is dirt cheap to do if you just include it in your blueprint up front.

-put a critical eye on incandescent lighting. In a cooling-dominated climate, consider lighting something like running an electric space heater in the house. In a tight house like this one, lighting will turn out to be a significant heat load! You just need more AC to get rid of the 90% of the juice that goes to heat instead of light with incandescent lighting. The more you can substitute energy efficient lighting for incandescents, the less you have to run AC to get rid of all that waste heat. In a heating dominated climate, at least the waste heat can be useful at times, but where you are, you're almost always going to pay twice for the inefficiency in the lighting- once for the light, and again to pump that heat out of the house. The trend towards lots of high wattage recessed can lights has really driven this home; 20 years ago nobody would have dreamt of throwing that kind of wattage at lighting, especially in lights that get used for hours and hours every day.

Yeah, the previous comment was a bit random, but do check out buildingscience.com and the Florida Solar Energy Center for other ideas on the best construction techniques available for energy efficiency.

OK, enough rambling for now. Hope the ideas prove helpful, if only as food for thought.

[Edited by wyounger on 11-17-2005 at 10:29 AM]

[wyounger]

If only I could get my brain to do as much forethought as afterthought, because I'm swamped in afterthoughts.

1. Years down the road, where are you going to find a good radiant heat technician to fix your system on short notice when it conks out in a cold snap? That's no problem up north, but could be an issue in your neck of the woods.
2. Yeah, I suppose you could bury your horizontal loop underneath your leach field if you get started early enough. If anything goes wrong with that loop, though, you are up a creek, and will have to just put in a new vertical loop and abandon the existing loop. Yes, loops are typically reliable, but that puts you in a position where most any loop problem is astronomically expensive because you can't get to any part of the loop to repair it. And if you have to work on the septic system, you would have to be super careful not to dig too deep and hit your loop.
3. I'm not sure how you would do wiring in your exterior walls with this technique, but that may be again a location where a little conduit could save a lot of trouble down the road- not just for signal wiring but even for basic electrical wiring. Everything will get rewired, eventually. Yeah the state of the art with wiring is good, but I bet in 50 years people aren't going to trust the wire that's buried a wall any more than we trust 50 year old wiring now. If you're going to build a structure to not be disposable, service access matters, and that means you can't really make anything so inaccessible that it can't be replaced without destroying stuff. Definitely you don't want it to require a jackhammer :D

[Edited by wyounger on 11-17-2005 at 10:52 AM]

[Black Adder]

Wyounger

Great reply well thought out and written, hats off to taking the time to put it all together.

[tclynx]

Thank you wyounger for your detailed reply.

This type of construction is very efficient and one of the quotes by David South Sr "Stepping over dollars to pick up pennies" about trying to use alternative energy with these homes is pretty apt. However if one must be off grid, they do make a good choice of structure so long as combustion isn't going to be the main source for heating and cooking.

I did see somewhere a combo air and ground source heat pump. It didn't require as much ground loop as a normal ground source heat pump. Any experience with combo heat pumps yet?

I do like the idea of the heat pump hot water. I actually think the tankless heater as backup for the HPHW would be a good combo since the tankless would only kick in if the water from the HPHW wasn't hot enough. Hence why certain models are appropriate for use in congunction with solar. On Demand or tankless heaters are becomming much more popular and so long as I can find a supplier in the area, I expect I can find service in the area as well. If I can't, then I'll have to re-think that. Perhaps the tank for the HPHW would need to be very large or more than one tank If I go with an on Demand system. As far as the hot water for the future expansion, would probably put in a separate system if putting in a separate HP for that end.

There is a good chance that we will still go with in floor radiant heat seeing as we will be pouring the main floor anyway. Since this uses lower temps it is efficient and the comforts of having warm toes while keeping the air temp reasonable is so appealing. I've had people tell me that their in floor radiant heat would be the last thing they would give up.

cem-bsee made a comment about elevating the home and Insulating the slab. I understand the elevating the location for the house and grading to keep rain and runoff from causing problems around the foundation. I understand insulating the slab and I think I know why you mention it but please elaborate. Also about the vapor barrier, check out http://www.monolithic.com to understand this particular construction method. (But please don't concider my design to be a dome just because Monolithic calls most of their's domes). The vapor barrier starts off life as an airform for forming the structure. It should later be coated with something to protect it from UV though it can last a while on it's own.

I definitely think ventalation and humidity controll are two very important parts of the design of this home. It won't take much to cool one of these (I've seen plenty of them cooled with only small window shakers south of Dallas Texas).

Thanks for answering my question about where ground loops can go (it would be handy if they could go several feet below a leach field but oh well, skip that idea). I will still be trenching a few hundred feet but unless that is enough to help with the combo air and ground source heat pump, I will only dig as deep as I need for the bamboo barrier since larger equipment would cost more to rent.

What about humidistat controlled vent fans for bathrooms?

I like the idea of timer controled kitchen vent fan.

Thanks for the mention of Dryer location and ventalation issues. I'll have to concider this a bit because I have always liked having the washer/dryer near the bathroom and bedrooms.

In such a sealed home most people recomend against any combustion apliances unless they are sealed and have outside combustion air supplied directly to them. There may be a problem here, we love cooking with a gas range. I don't know of any sealed gas ranges. How can we make this safe? I was supporting the idea of an indoor/outdoor kitchen arrangement where there would be a door off the kitchen to a patio/outdoor kitchen living area for the grilling and barbaqueing etc. We could have electric inside and keep the gas, charcole and wood outside but he has gone back to wanting the gas cooktop inside.

Ok, thanks again and I'll have to check out BUILDINGSCIENCE.com

[wyounger]

Originally posted by tclynx
Thank you wyounger for your detailed reply.

I did see somewhere a combo air and ground source heat pump. It didn't require as much ground loop as a normal ground source heat pump. Any experience with combo heat pumps yet?


Nope. I am no longer a fan of being on the bleeding edge, though. It's too easy to get burned because the technology is immature or because nobody knows how to fix it when it does break. If you can get your heat gain down low enough, though, it starts getting very hard to justify an expensive and elaborate cooling system that's ultra-efficient when you can be reasonably efficient for a lot less. It's the same story where a 10% fuel economy boost for a small car is kinda nice, but the same 10% would save a lot more gas in a big truck.



I do like the idea of the heat pump hot water. I actually think the tankless heater as backup for the HPHW would be a good combo since the tankless would only kick in if the water from the HPHW wasn't hot enough. Hence why certain models are appropriate for use in congunction with solar. On Demand or tankless heaters are becomming much more popular and so long as I can find a supplier in the area, I expect I can find service in the area as well. If I can't, then I'll have to re-think that. Perhaps the tank for the HPHW would need to be very large or more than one tank If I go with an on Demand system. As far as the hot water for the future expansion, would probably put in a separate system if putting in a separate HP for that end.


Tankless has a certain beauty for backup, I'll agree. But the energy savings you anticipate may not really there. People talk and talk about these huge standby losses associated with keeping a big tank of water hot all the time. The reality, with electric tank water heaters, anyway, is that those standby losses are trivial. Gas tank units are a different story, though; they lose a lot of heat through the flue. Anyway, if you use a HPWH to heat a "preheat" tank and the HPWH is set to heat to 120 F, and you set the thermostat for the second (regular electric) tank to 110 F, the second tank will rarely ever switch on its heater... just as if you put a tankless backup in its place, the tankless unit would rarely kick on. The beauty of high efficiency devices is lost when they aren't used enough justify their existence. Now if you just want the tankless to save space, that may be a different story.

As for a second hot water system for the addition, you certainly could, but you probably wouldn't need it for reasons of capacity. I can see wanting to avoid long waits for hot water and the need for circulator pumps, sure. If you already know roughly where the addition would go, though, consider just putting the water heating system close to where the addition would join the original structure. Then you won't have super-long plumbing runs in any direction.



There is a good chance that we will still go with in floor radiant heat seeing as we will be pouring the main floor anyway. Since this uses lower temps it is efficient and the comforts of having warm toes while keeping the air temp reasonable is so appealing. I've had people tell me that their in floor radiant heat would be the last thing they would give up.


Well, OK. But I must ask- were these people in Florida? And were their slab edges insulated? :D



Thanks for answering my question about where ground loops can go (it would be handy if they could go several feet below a leach field but oh well, skip that idea). I will still be trenching a few hundred feet but unless that is enough to help with the combo air and ground source heat pump, I will only dig as deep as I need for the bamboo barrier since larger equipment would cost more to rent.


I am no ground loop expert, by any means, so don't take my advice as golden. Those are just the issues I would worry about if I were in your shoes. If a real expert can address the concerns I suggest there, listen to the real expert. :)



What about humidistat controlled vent fans for bathrooms?

I like the idea of timer controled kitchen vent fan.


Yeah, you could use humidistats too. The downside I see is that if the whole house ever did get humid for some reason, the last thing you would want in this climate is all of those bathroom fans kicking on autonomously. And with a humidity controlled exhaust fan, you still need a way to tell it to turn on because of... odors... and ideally it could continue running after you leave the bathroom and still turn off after a reasonable amount of time. Maybe you have a fan in mind that accomodates all those needs. For a retrofit, though, the timers are much, much easier!

I have replaced all the regular light switches in my bathrooms that controlled the vent fans with the mechanical timers I mentioned. They are simple, cheap, fit in the same spot the light switch would have occupied, and it lets me use a simple, cheap exhaust fan (which in my case is already in place). A timer also lets you keep the fan off until you really want it to run. I frequently take my shower with the fan off (peace and quiet, or listen to the shower radio). When I finish and leave the bathroom, I just crank the timer and let the fan do its thing after I'm gone. Sure, quiet fans are available, too, but again, at least for a retrofit, the timer is cheaper and easier.

The only downside I've found with just using the timers is that occasionally you really want them to stay on for long periods. I just painted one bathroom, and had to keep going in there to turn the timer for another hour of exhaust time until all the paint fumes were gone.

I used Intermatic FD-60 timers, like this: http://www.rewci.com/infd60inspwo.html



Thanks for the mention of Dryer location and ventalation issues. I'll have to concider this a bit because I have always liked having the washer/dryer near the bathroom and bedrooms.

In such a sealed home most people recomend against any combustion apliances unless they are sealed and have outside combustion air supplied directly to them. There may be a problem here, we love cooking with a gas range. I don't know of any sealed gas ranges. How can we make this safe? I was supporting the idea of an indoor/outdoor kitchen arrangement where there would be a door off the kitchen to a patio/outdoor kitchen living area for the grilling and barbaqueing etc. We could have electric inside and keep the gas, charcole and wood outside but he has gone back to wanting the gas cooktop inside.


This will all end up hinging on your floorplan.

You could just make the laundry room airtight to the rest of the house (unconditioned) and give it a dedicated fresh air intake so that whatever the dryer throws out gets replaced with outdoor (unconditioned) air. Much better than what I've been doing lately, which is to open a window a few inches to use as a make-up air source and let the HVAC cope as best it can. There's always the garage, too, which might or might not be close.

Oh, please, somebody start making a direct vent clothes dryer! In the meantime the only other option I see are condensation dryers, which are sort of like the marriage of a clothes dryer and a dehumidifier. Instead of throwing away the humid air in the dryer, you dehumidify the air and use it again, closed loop style. Neat, and doesn't depressurize the building, but all the waste heat from the dehumidification gets dumped into the room, so you replace the issue of needing make-up air with the issue of waste heat. A great idea in heating dominated climates, though. They're rare and exotic in the US, though, and all I've found of them (Bosch) is in the $1,200 range.

You can cook safely with a gas appliance in a tightly sealed house. You just have to turn on the exhaust fan whenever it's running and provide enough make-up air to replace what you're blowing outside, though, which pretty well kills the efficiency of the tight house thing. Otherwise... maybe you could put the kitchen outside the building envelope completely. Like a very fancy screened-in porch :) LOL

Seriously, I don't see a way around efficiency demanding that combustion be kept outside the building envelope, so try to find a way to have some joy and still cook with electricity while you're indoors. Maybe one of those fancy new induction ranges will be fun enough.

[Edited by wyounger on 11-17-2005 at 01:15 PM]

[tclynx]

I need to check out those new induction ranges.

As far as wiring (conduit) in the outer shell of the structure, yes I intend to put in extra conduit for future ease. Only the really cheep shell builders run the wiring through the concrete without conduit.

Thinking about the tankless heaters. I know they make smaller versions of such things meant more for putting close to the point of demand to take the chill off the wait for the hot water to arrive but these are probably too small to operate as backups. They are only designed as subistutes for circulator pumps on the hot water lines. Oh so many things to figure out.

One of the biggest unknowns to me is how/where best to run the ductwork and put the air handler. Generally no attics in this type of construction. Good point, ducts run in conditioned space. Bad point, where to hide them. I do expect to have a loft space over the bedrooms/bathroom. This loft could have a utility closit to house the airhandler and ducting could run in the floor of the loft which would be the ceiling of the bedrooms etc. The main living space would be wide open with high ceiling. I don't really mind some exposed ducting so long as it looks good. We are also planning a soffit around the main living area at about normal ceiling hight. I don't know how large this soffit would need to be to accomadate ductwork if that is possible. We were planning on it housing some lighting so it might be a bit crowded.

Of course now I may be getting into details that must be worked out directly with a system designer and contractors. I'm still open to suggestions and recomendations of things I should keep in mind.

Thanks again,


[Edited by tclynx on 11-17-2005 at 05:02 PM]

[aircooled53]

Ground Source Heat Pump
Closed loops

Check out Commandaire split with/de-superheater GSSD03010C00110C
Trane/TWE037E13FB variable drive /air handler
Perfect Fit Filter
Pro 8000 Thermostat

[dave davis]

Can't speak on HVAC but will put 2cents in on induction cooking. If you like gas, induction will disappoint. Needs specific pots/pans ie magnetic, and not always the pans you want. Then, even w/expensive pans you get hot spots for saute or pan frying. Works great for simmers and boils water faster than you can imagine. Also hums as it cooks. We have a "Sauter" induction range that is impossible to service and I look forward to its demise to replace with a gas cooktop.

[tclynx]

Thanks for the input Dave. It sounds like the induction cooking is more like the worst electric cooktop possible. Sounds a little like the cool heat soldering irons (with those the tip is split and contact with a conductive item to be soldered completes the electrical circuit to heat up the iron), not very practicle at least for my line of work. We may have to make some compramises between efficiency and cooktop. Not sure which way it will have to go.

I'm sure we will make some compramises in efficiency since the other half does like to open windows when the temp is comfortable. That will mainly affect the humidity so I want a system for humidity control that will be able to handle the extra load.

[tclynx]

Anyone have opinions on duct placement in such a home where the outer shell does not provide any space for consealed ductwork and there is no attic. There will be interior walls and a ceiling over the bedrooms/bathroom.
What types of ductwork might be good options. Most everything will be in conditioned space except for outdoor units. Can anyone share links for good looking exposed ductwork if I must run it along the interior surface of the shell?

Thanks

[perel]

I beg to differ on induction cooktops.. love them myself. Heats much faster and better than a normal electric range, no gas smell, and auto shutoff. The last one is important for me as I'm rather absentminded - unlike gas or regular electric, induction ranges will detect a pot that's boiled dry or a burner that's been left on with nothing on it and shut that burner off.

I think induction combines the best of electric and gas, but then again I don't love gas cooktops. I've never had a problem with the pan restrictions either - almost all of my cookware worked fine. In any case, induction feels much more "gas-like" than a regular resistance electric cooktop, so it's certainly something to think about if you're trying to avoid having any open combustion appliances.

[tclynx]

So an update to the house design.
closer to 2100 SF and alot of extra high ceilings.
Had to give up the idea of geothermal, just doesn't fit into the budget.

So How important is it going to be for me to insulate the slab in central FL? The type of construction makes it very tight and the concrete thermal mass on the inside is high. How big a differece will the thermal bridging of the slab make?

Is it going to cost me more to insulate the slab than it will save me in 20 years? I really don't want to be "Stepping over Dollars to pick up pennies" in other words.

[aircooled53]

Then might want to check out Carrier Infinity system heat pump with maybe 17.0 SEER rating or 19.0 with (2)stage cooling.Also I would agree with the others in ERV installation of fresh air on such a tight home; filtration is a key factor in your home comfort and health.

[tclynx]

I agree about the ERV and need ing fresh air. One thing this house design does have is extra air volume that could help us out in a short term situation when it might be undesirable to bring in fresh air but that only helps for several hours.

Any comments on the slab insulation? I don't even know if it is advisable to use foam insulation below grade in the SE due to termites. Not that they eat it but insects may like nesting in it.