I’m the new kid on your block and I have a question for you all. If you were to build your dream home from scratch, you want it to be very energy efficient, but also a very healthy enviroment – what would the composition of your house be and why? The building industry keeps throwing new products at us all the time. Would you build with SIPS, ICFs, blown cellulose, blown fiberglass, open and/or closed cell spray foam insulation between wood studs, batt insulation (anything else you prefer that I didn’t name)? What type of heat/cooling source would you choose and why?
I draw house plans for architects, builders and home owners. I would like to find out what you have found to be the most cost effective/energy efficient building construction. MOLD has become a nasty 4 letter word in our profession. GREEN is getting more attention as well. I have seen SIP panels that the ants seem to like better than anyone. ICFs are awesome as long as you only build one story tall. (You can build more than one floor, but it becomes much more involved!) Some of the spray foam products seal your house tight as a balloon – what about indoor air quality then? Sorry this has become so wordy, but I would like to be able to advise home owners on a building system (roof/walls/foundation and HVAC) that is energy efficient, healthy and cost effective. What is you take?
Oz-man
Replies
Welcome to BT. You don't ask for much in your opening query, do you? LOL
Most everybody here knows I went with passive heating/cooling in a concrete house (cast-in-place). Today we'll be 90º outside, 70º inside, passively.
Air changes are critical, for everybody. That's the V in HVAC, generally ignored by HACs here. We're very happy with .5 ACH (although I've been assured by more-knowledgeable here that I'm overdoing it), small positive pressure inside so leaks go out. Along with air changes, managing humidity is critical. Over 50% rh promotes mold growth. Pick your system for control, ac is most common.
Our tiny air system (for 20k cu ft) uses a dehumidifier and heat pump water heater byproduct (cool dry air) after initially filtering incoming air. Ducted everywhere, including closets. Best indoor air I've encountered. Guests notice.
Last similar house built here appraised 50% higher than construction cost. Shell was one of many factors, but a significant one.
You're not gonna get much concensus on "be able to advise home owners on a building system (roof/walls/foundation and HVAC) that is energy efficient, healthy and cost effective". You will get testimony on the effectiveness of almost every building strategy. One size (method) does not fit all.
PAHS Designer/Builder- Bury it!
Dear VaTom
I would have to agree with your thought that everyone has their pet construction ideals. The 2 homes that I have built are similar in the sense that their floor plans are open, they have lots of exposed structure in them and I enjoyed the creation of these structures. My first home was timber frame with SIP walls and roof. I also took advantage of passive solar design. (Low north wall & lots of glass to the south) It has been very inexpensive to heat/cool. My SIP panels were not treated though. I built this house in '85. Wood heat was adequate when I was home. It also had a heat pump, but used very little. It does lack in ventilation.
The 2nd home was stick built with blown cellulose walls. The roof is 5 1/2"EPS over 1 1/2" blue board over exposed 1x8 T&G roof deck over exposed 2x8 rafters. The house is approx 3800 sf of living space with lots of natural light in its design. The only problem encountered are the windows will sweat during cold winter nights. This house uses forced air heat and does have a built in humidifier. The air filter is changed regularly - just wish the windows would not sweat...The walk out basement is ICF where it is in contact with the ground and stick frame elsewhere with blown cellulose. I also have 4 foot overhangs for wall protection, shade and aesthetics.
Have you or anyone else built using Icynene Insulation System? If so how has it performed? Would you recommend using this insulation system? I am about to design another craftsman style home for a client and that is why I am asking for the feed back.
Thanks for you time and response. Oz-man
My first home was timber frame with SIP walls and roof...
Exactly what my client moved from when he commissioned the concrete house I built for him. He'd give you an earful on why he'd never go back. Not that it was a bad house, new owners think it's fine.
Mostly about cost, both upfront and maintenance. Large performance difference. Air source heat pump both places, wood heat primary for the P&B. Major difference in elec bill. Happens when you need neither heating nor cooling.
I was very curious how his house would work summers. Hot, humid here. His ac is primarily dehumidification. House stays the same temp as ours, similar rh, and same elec consumption as ours. Difference is he sprung for the heat pump (to aid financing) and I buy used dehumidifiers for 50 bucks or less, keep a spare on hand. He never bothered to install his heat pump water heater, gave it away.
XPS is adequate for these places. When I did heat loss/gain calcs I discovered that the 2½" I used on my exposed walls was excessive. The next house got 2", similar performance. OTOH, ICFs wouldn't work well for me, much as they're touted by extremely happy users here. Windows are the one area I don't quite have under control. But we don't have your problem.
Your sweating windows have a reason, dew point. Do you know why it's reached? Need that before you can effect the best solution. Either dryer air or warmer glass.
Good luck with the new house. A search here will come up with posted icynene experiences. PAHS Designer/Builder- Bury it!
Welcome to Breaktime.Now fill out yer danged profile, will ya ???(-:
Despite the cost of living, have you noticed how it remains so popular?
I am completing my 2 story ICF wall house with SIP roof on the Northern California coast. The SIPs are Borate treated so the bug issue is taken care of. SIPs are a good choice for the roof in earthquake country, but I would consider using one of the ICF concrete floor systems for a roof in hurricane or tornado prone areas. I used one for my second floor deck.
Building a 2-story with ICF is no more involved than anything else. You brace and pour from the inside. Either way you need scaffold for installing the exterior finish. With ICF and/or SIPs, get someone who really knows what they are doing for energy calcs.
Make sure you have a method to get it sealed well, especially the ICF to SIP roof connection. There are ICF wall houses in this area with truss roofs that are not much more energy efficient than all stick frame because of infiltration. I used 8x20'+ SIPs to reduce leakage potential. Making SIP seams very air tight is much harder than you would think. I did add seam tape inside but I know the seams leak a fair amount and I had a very experienced and reputable installer.
Any super-tight structures should consider installing an HRV or ERV unless you leave doors and windows open most of the year.
High thermal mass does have interesting properties. This has been a record cold winter here in terms of degree-days. The lowest inside temperature all winter was 53° F with plywood doors, open vents, and no heat. All that concrete, especially the two floors, is a thermal battery that moderates. It is staying around 62° 24/7 now that the solar gain is up. The downside it will also make hydronic heat very slow reacting.
Edited 5/28/2007 9:57 am by CJD
My dream house is all fine concrete, thick glass, and brushed stainless steel. All finishes are the structure. No maintenance ever; lots of thermal mass. Flat pavers through a koi pond to get to the front door.
Think Richard Neutra. Sorta.
View Image
View Image
Ground source heat pump; solar to run the pumps. Well. Windmill. Minimal furniture. Overlooks LA city grid at night; ocean during the day. Cantilevered infinity-edge pool.
Schubert's Piano Trio in E playing softly in the background in high, spare rooms.
Ahhhhh . . .
Forrest
Edited 5/27/2007 10:56 am by McDesign
Forrest,When Neutra was teaching architecture, the students had a joke that the best question to ask him was, "Professor Neutra, what is the best material to use in constructing a steel house?"It seems one would want a lot of warmth, softness and texture inside such a home to balance the unyielding characteristics of the primary materials.Bill
< . . . one would want a lot of warmth, softness and texture . . .>
No! I have that now, in a big ol' Queen Anne! It feels like "clutter" after a few decades!
DW says the Neutra house must be for the new wife.
Forrest - secretly dreaming of living in sculpture
Love it. Saw one of those HGTV this-is-too-much shows featuring several mansions. Some guy had one for sale for 22 or 29 million--at that price the extra 7 mil won't hurt you. Said it too, 10 minutes to walk from one end to the other. That stated here just to let you gauge the size somewhat. Anyhow, the roof was stainless steel. All of it. Roof cost $750K. Ouch!
Not intending to hijack thread here but...
You mentioned solar panels to power heat pump,I have ground source heat pump. I had one solar "expert" come and take a look he said I'd be spending quite a lot to run house and heat system. Do you know tech. details about such a system?
I need to find the article - I called and talked to one of the guys after reading it. Some deal between Habitat for Humanity and Oak Ridge National Lab.
I'll track it down and post a link.
Tell me about your system - is it direct-injection, wher the actual refrigerant goes in copper coils in drilled wells, or what? Do you like it? I'd love to do one for this place when the three conventional systems wear out.
Forrest
I'm not sure about direct injection. It's coils filled with refrigerant run into our pond. It came with the house (one of the reasons we bought the place) so I haven't had a chance to get to know it very well yet. So far it seams affordable to run and low maintenance. The shell of the house needs some updating so we aren't getting the full savings we hoped, but given some time I think we will have a very efficient set up.
The only neg. I have is its a forced air system. I'm not to fond of forced air to begin with and ground source heat pumps blow slightly cooler air then a traditional setup. So it doesn't feel all that warm when it blow on you, that said it does heat the house to whatever temp you want very well.
Hey, Greetings! Welcome to BT! Thanks for opening up with such a good question for all of us.
I've been here on the same quest for about two months, asking for smaller parts of the puzzle and getting some excellent replies. I look forward to reading every reply, as I'm sure many others do too.
Hudson
I've been here on the same quest for about two months, asking for smaller parts of the puzzle and getting some excellent replies.
I've read at least one of those threads.
Could you tell me the name of the thread or the links?
I would like to read through those again.
Thanks
Rich
Edited 2/7/2008 1:42 pm ET by cargin
Sorry to say that I didn't make note of those threads.
Most of the topics that have helped me have been on two types of building, PAHS and ICF, both of them new to me. Some others have been on using SIPs on timberframes.
I also got some interesting insights from Mike Smith's excellent photo essay on a new super-insulated radiant slab home he built last year. He shows a lot of details on Mooney walls and the same technique applied to ceilings, using cellulose insulation.
Hudson
Thanks anyway. Just wanted to see what you were planning on building.
Rich
Thanks for your interest. I haven't written about it but I'm planning on an ICF home, three levels, two below grade on the uphill side. Perhaps an exposed timber truss roof with SIPs.
I'm also going to incorporate some of what I've learned about PAHS as an experiment in moderating temperatures, holding energy costs down.
My main objective has been to build a home which will be easy and relatively inexpensive to live in, over the next fifty years, while taking full advantage of the excellent scenic views available on the side hill lot.
If I were building a single story home on a budget, I'd be inclined to follow Mike Smith's fine example, the house he did the full photo thread about.
Hudson
I am not in a position to build a house right now but I would go with ICF. The SIP make me nervous. Too many stories of bad moisture management. I don't know enough about them to build around the variables.
We have alot of ICF basements and whole houses around here with amazing results.
I will have to Google PAHS. I don't know what that is.
I saw part of M Smith's photo thread.
Rich
Glad to hear that you have some working examples of ICF homes close by. Can you elaborate on the "amazing results"?
There's are several builders on BT who've used SIPs with success and have passed on their experience on best installation methods here.
You can use the advanced search feature above the topics column to find threads on PAHS. We have one strong advocate of that system, VATom, on the board who is currently living in the first one he built. He's very knowledgeable and has shared much of his experience on BT.
Edited 2/9/2008 10:09 am by Hudson Valley Carpenter
Hudson
PAHS is what we used to call earth sheltered. Right?
Used to be fascinated with the concept. But I think there are too many problems with earth on the roof.
With the superinsulation techiques, I am not sure the earth sheltering is cost effective and the lack of windows in 1/2 the house is problematic.
ICFs around here are, are telling me about very sound proof, using the smallest possible furnace (that one was built 6-8 years ago) leaving the A/C off until mid summer.
Others have told me about heat bills for the winter being the same as comparable sized homes pay in 1 month.
Rich
That's right, a mostly underground controlled environment. The roof doesn't concern me as much as the other limitations imposed by the concept. I'm considering using their "umbrella" idea to help moderate the temperature of the surrounding soil.
Thanks for the report on your local ICF homes. That's very encouraging. Do you know which ICF products they are made of? Any difference in performance?
Hudson
Most around here are Lite Forms. The company headquarters is just 30 miles down the road.
Right now they are mostly 2" insulated forms, with 2.5 as an option, and 8" walls for the basement and 4" walls above the basement for a single story house.
We have some Rewards, but I have no experience with them.
Rich
Rich,
That's all very useful information. Thank you.
Peter
curious,where you located? oz = ks ozarkcraftsman = mo. or arkansas?
if money is no object icf to the rafters,then foam on the underside of roof. geo thermal hvac system,then i probably would need some crappy windows to let a little air blow through!
i'm out here by myself when i say i have no problem with "some" fresh air blowing through my house. my thought is thats one of the problems of this mold problem,the tech is there to seal a house tight anymore. did you ever hear of them needing to tear down a house built in the 30's to the 60's because mold was growing everywhere?i haven't larry
hand me the chainsaw, i need to trim the casing just a hair.
Edited 5/31/2007 10:55 pm by alwaysoverbudget
bump
If you're asking about energy-efficient and healthy indoor environment and cost-effective AND resource-efficient and healthy to the outdoor environment, this is what I've developed after 25 years of building superinsulated and passive solar homes:
http://www.builditsolar.com/Projects/SolarHomes/LarsenTruss/LarsenTruss.htm
excerpted from:
http://forums.taunton.com/n/mb/message.asp?webtag=tp-breaktime&msg=99930.1
Solar & Super-Insulated Healthy Homes
Oz man,
Welcome to Breaktime.. You can look at my dream house if you go over to the left and enter 85891.1 and 94941.1
It's a combination of ICF's and SIP's
I'll love to give you the ins and outs of both if you are interested..
Stick built is terribly inefficent and not cheaper if you do-it-yourself as I did.. It's real model T stuff. If on the other hand you are teaching contractors on your nickle or the contractors building with either don't have any real competition then you will pay a premium for either one..
There is no valid reason for that.. Here in Minnesota contractors are building with ICF's for the same price as stick building costs.. they've had enough experiance to learn how to do it efficently and competition is forcing them to do so.. In fact if you don't offer ICF construction at competitive pricing you most likely won't be building. Things are that tight around here..
The final reason to build with ICF's or SIPs is because of energy savings..
I used to pay $500 a month in Dec./Jan to heat my old stick built house.. it was 1/2 the size with 1/3 of the number of windows.
This year using the exact same furnace not even properly installed I spend under $200 for Dec. & Jan. Summer air conditioning costs maybe $15 dollars per Year! When it's 90 degrees outside inside it's still in the 70's you only need A/C a few days of the year that approach 100 degrees.
Finally there is the stength and durability issues.. While nothing will approach the strength and durability of a ICF home, you should know that SIP's are 200% sronger than stick built.. Untill you experiance the strength and quietness of a SIP house you have no idea just how solid they can be..