GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Audio Play Icon Headphones Icon Plus Icon Minus Icon Check Icon Print Icon Picture icon Single Arrow Icon Double Arrow Icon Hamburger Icon TV Icon Close Icon Sorted Hamburger/Search Icon

Community and Q&A

Where to start?

Jason Kibbe | Posted in PassivHaus on

Hello,

I’ve read about passive houses for some time and understand the basic design principles. I have a piece of land that I am considering building a new passive house on and am looking for some guidance.

I currently have a one-story 4 BR, 2.5 bath home that has a finished basement. I’m looking to build a home that has 3BR and 2 bathrooms. I think I can sell my current home and have enough cash to pay off what is left of my mortgage and build a new home with the proceeds. My brother-in-law built my current home and can build my passive house as long as I give him the correct specs (selling him on the idea would be helpful, too!).

I confess my main motive for building is a selfish one. I’m not looking to spend a ton of cash just to be green, though I certainly don’t mind making some efforts to go in that direction. I primarily want to build an inexpensive house (because I’m cheap) that will have low energy requirements (also because I’m cheap & am concerned about rising energy costs).

I realize that a passive house will require some upfront costs for insulation, windows, and the like, but I don’t spend a bunch of extra money just so I can call the house ‘green.’ I realize I’m posting at ‘green’ building advisor, but I’ve read about some homes that are 3000+ sq. ft. vacation homes with all the latest ‘green’ features that cost 500k — I just want to be upfront about my motives and budget. Building a passive house with Energy Star appliances, low-flow sinks and toilets, and CF bulbs is ‘green’ enough for me!

That all being said, I wish there was a repository of building plans and suggested materials for use in a passive house. I’ve been gleaning information from this site and others, but still struggle with what are the *best* heating (radiant floor, heat pump, etc.), HRV, (brand, specs. to look for), window (brand, rating), water heater (elec., propane, tankless), etc. options for me.

If you were building a 3 BR, 2 bath (1500-1700 sq. ft.?) passive house in south-central PA (N 40, W77) on about an acre of land, what design and construction materials would you use, esp. if you’re trying to keep costs down?

Would you suggest building a one story house or a two story? Basement or slab? Earth warming tubes with HRV or not? What kind of exterior siding? What kind of floor materials?

I realize this is a bunch of questions at once, but this is overwhelming for me! Just throw down your opinion as to what you think some of the most important considerations are and what I’m missing!

Thanks in advance!

Jason

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Replies

  1. Steve El | | #1

    I have friends who built an "earth ship" using adobe filled and plastered automobile tires, and others who've done strawbales.... and one of those is in N PA..... They did most of the labor themselves. Just to complicate things further, there's the non-mainstream building types!

    have fun, great question

  2. T Shepp | | #2

    You can build a Passive house from almost any standard building materials....nothing fancy needed. The biggest concern is can you orient the house due south or at least have lots of glazing on the south side. You also want some mass to capture the solar heat (concrete/tile floors or stone wall). Lots of insulation....ADA.....HRV....I could go on. A Passive house is not much more expensive to build than a normal house....it's how you build it that is important. Get a good book on how to build a Passive house (not PassivHaus) and search the web. Lots of info out there.

  3. GBA Editor
    Martin Holladay | | #3

    Jason,
    Tim's answer assumes you want to build a passive solar house. Some readers might assume you want to build a house that meets the Passivhaus standard. Which of these two types of houses did you have in mind?

    Some observations:

    1. If you want to build a house that meets the Passivhaus standard, you will almost undoubtedly need to hire a Passivhaus consultant. Your house will cost significantly more than a house that does not meet the Passivhaus standard. The Passivhaus standard sets a very high bar, and such homes are not cheap, regardless of what some people claim.

    2. Assuming you don't need to meet the Passivhaus standard, but just want to build a superinsulated house, I would recommend the following:
    - a simple rectangular shape (no bump-outs), with the long axis oriented east-west, two stories.
    - about half of the windows oriented to the south, with few windows on the north side.
    - aim for R-20 basement walls, R-40 above-grade walls, and an R-60 ceiling.
    - frame your walls with two rows of 2x4s, total thickness 12 in., insulated with cellulose.
    - build an unconditioned ventilated attic, with deep cellulose insulation on the attic floor.
    - use Canadian triple-glazed casement and fixed windows with fiberglass frames.
    - install an HRV with dedicated ventilation ductwork.
    - heat it with a Mitsubishi Hyperheat ductless minisplit.

  4. Jason Kibbe | | #4

    Thanks for the input, everyone.

    Marvin, I would like to pursue the passivehaus standard, but would settle for superinsulated if that will give a similar result for less money. I appreciate you spelling things out for me clearly -- it's exactly what I'm looking for!

    How many degrees off of the E-W axis can I get away with and not lose the S facing benefit. With the building lot I have, E-W is probably 15 deg off of being parallel to the street.

    What effect would building a 1-story have? I'm spoiled by having everything one floor right now!

    Finally, any specific HRV manufacturers I should look at?

    I should have specified that I want to build a house that looks and feels much like a 'regular' house!

    Thanks again!

    Jason

  5. John Brooks | | #5

    Jason,
    I don't know much about Cold Climate Foundations...
    But I would suggest that you consider Building a One Story House with NO BASEMENT or crawlspace.
    If you can't live without storage space for cars and "stuff" build a "shed".

    The advantage to a one story(with flat ceiling) is that you will have less Exterior wall surface area and more "attic floor" area.
    Attic floor area is where you will get more bang for your dollar as compared to Exterior wall area.

  6. John Brooks | | #6

    I like Martin's Post.
    I admit that I once thought Passivhaus might be "the solution" for North America.
    I was angry at Martin, John Straube and Robert Riversong for Suggesting that some aspects of the Passivhaus System were "murky" and or not-so-logical.

    I am always looking at US PH examples and so far have not seen one that I would call practical.
    (please post a link if you have seen one)

    Perhaps Passivhaus is too extreme.
    I have lived in homes and apartments that would fit inside the "mountain of foam" shown in the photo below.

  7. John Brooks | | #7

    3 suggestions for affordable, durable High Performance
    AVOID VAULTED CEILINGS
    AVOID VAULTED CEILINGS
    AVOID VAULTED CEILINGS

  8. J Chesnut | | #8

    If you were building a 3 BR, 2 bath (1500-1700 sq. ft.?) passive house in south-central PA (N 40, W77) on about an acre of land, what design and construction materials would you use, esp. if you’re trying to keep costs down?

    I think an important consideration here is whether you hire a professional to design your home. Expectations are different but in my opinion as a designer small homes are more difficult to design well than large homes.
    Additionally the performance of the thermal envelope starts with a good design. Architects typically charge from 7%-12% of the construction budget for design fees.
    Of course I'm biased but if you find a good designer I think it is worth the investment especially when you set out to create a tight well insulated thermal envelope with fenestration that leverages passive solar heat to reduce the heating demand. The right designer would be familiar with passive solar design principles and be able to use energy modeling software to verify the design.
    Poor passive solar design can lead to higher than expected energy consumption and overheating in the summer months and the devil is in the details.

  9. J Chesnut | | #9

    2. Assuming you don't need to meet the Passivhaus standard, but just want to build a superinsulated house, I would recommend the following:
    - a simple rectangular shape (no bump-outs), with the long axis oriented east-west, two stories.
    - about half of the windows oriented to the south, with few windows on the north side.
    - aim for R-20 basement walls, R-40 above-grade walls, and an R-60 ceiling.
    - frame your walls with two rows of 2x4s, total thickness 12 in., insulated with cellulose.
    - build an unconditioned ventilated attic, with deep cellulose insulation on the attic floor.
    - use Canadian triple-glazed casement and fixed windows with fiberglass frames.
    - install an HRV with dedicated ventilation ductwork.
    - heat it with a Mitsubishi Hyperheat ductless minisplit.

    Jason if you found it worthwhile to hire a professional to design your home don't discount a Passivhaus designer based on Martin's comment. Martin's specs here could possibly meet the PH standard for climate zone 5 depending on the size of the home. A Passivhaus designer like any other professional is responsible for helping you meet your budget. If meeting the budget means falling short of the voluntary Passivhaus standard that is possible. The benefit you still receive from hiring PH designer is energy modeling that will help make intelligent decisions about the fenestration to optimize the use of passive solar for meeting the heat load without overheating in the summer. A good PH designer will also pay the appropriate attention to air tightness and avoiding thermal bridging that could undermine the performance of the insulation.
    Its not only PH designers that can accomplish this, but I would recommend only hiring designers with the capacity to energy model passive solar heat gains (and the associated possibility of overheating) or someone with a portfolio of succesfully operating passive solar homes.

  10. John Reimers | | #10

    John Brooks: Regarding your admonition about vaulted ceilings. Are you referring to a ceiling where the vault and roof are one assembly or any type of vault? For example is there anything wrong with a false vault where there is adequate room for insulation and venting below the structural roof?

    Is there anything wrong with several ceiling heights which give the building more interest in my opinion? I understand that the more box like the building , the easier to air seal. Wrong may be an incorrect word here, inefficient is a better one.

    John

  11. Matthew Nolette - So Maine CZ 6A | | #11

    I'm with John Reimers. I think John Brooks objection is to cathedral ceilings where the thermal layer is directly or nearly directly against the roof sheathing. There are a lot of ways to enhance the interior spaces with vaults that still allow for substantial ceiling plane insulation and use common building materials. Think raised-heel truss.

    On a different note, I'm a construction estimator by trade and I'd second Martin's advise to go with two-stories. It's less expensive to reduce the building footprint and put the additional bedrooms on the second floor.

  12. John Brooks | | #12

    I am trying to suggest the most AFFORDABLE
    for a small 3 bedroom 2 bathroom house

    Mathew,
    when you compare 1 story to 2 story costs... are you including a superinsulated basement?
    also are you including the cost and additional square footage of Extra Thick Double Walls like Martin Suggested?

  13. John Brooks | | #13

    John Reimers,
    I think if you want to take a step beyond Affordable...
    then Varied ceiling heights is good.

    Also for a not-so-small home ..... then 2 story can make sense.

    And if you want to add more cost AND more risk then you can include vaulted ceilings.

  14. Daniel Ernst | | #14

    If you follow Martin's list of features, then your energy demand will be dominated by domestic hot water, appliances, and plug loads. So, add the following:

    * Condensing gas water heater, or hybrid (instantaneous with small buffer tank)
    * Energy Star appliances
    * Switched recepticals for your various plug loads---TV, computer, etc.

    Those things don't exactly lend themselves to affordability . . . .

    Martin - You didn't mention airtightness. Airtight sheathing or ADA approach? Or both? ;)

  15. Kevin Dickson, MSME | | #15

    My top home design recommendations in no particular order:

    -Frost protected slab on grade - R20 min perimeter insulation
    -R28 min wall, R60 min roof (many methods available, the consensus is to use cellulose)
    -Design for a "conditioned attic" bonus room or no attic (flat or shed roof)
    -Simple forms, rectangular or square footprint
    -100% electric, no natural gas
    -No sliding doors or windows, or even exterior french doors
    -If you have sunshine available, high SHGC south (and north) windows, solar DHW ($3.5k max)
    -Triple pane windows if you can find them at a reasonable price
    -Fiberglass framed windows for longevity and other thermal reasons
    -DO hire a HERS rater ($1500 max, DON'T waste money on LEED or PH certification
    -Plan for future photovoltaic system, or install now if there are local rebates
    -small, cheap HRV ($1000 max total) or just WhisperGreen exhaust fan for ventilation
    -Minisplit heat pump or PTHP
    -Induction cooktop, small range hood
    -PEX pipe using 1/2" home runs

  16. John Zito | | #16

    I'm with John Brooks about vaults. It's more volume to condition than a flat-plane ceiling.

  17. John Brooks | | #17

    And Kudos to Martin for suggesting an Affordable and Not-So-Foamy strategy
    at Post #3

  18. Lucas Durand - 7A | | #18

    John, I agree with you that super-insulated basements (even in accordance with Martin's suggestions) are less affordable.
    I can't see how a vaulted or cathedral ceiling could be as/more affordable than a flat ceiling with unconditioned attic.

    Talking with friends who have recently bought "production" style homes, it seems that one reason energy-efficient homes are considerd "too expensive" is the assumption that envelope improvements have to be paid for in addition to interior finishing costs.
    Given a choice between spending money on envelope improvements or maxing out on expensive trimmings, it seems that the "average consumer" will usually choose the latter.

    I wonder how many production builders offer "envelope packages" in the same way that they offer "finishing packages"?

  19. John Brooks | | #19

    Vaulted Ceilings and Cathedralized Attics score much lower on the "Straube Roof Assembly Scale" than Simple Ventilated Attics........

    There is a durability issue with vaulted ceilings that is seldom discussed.
    The "warmest & wettest" air is funneled and concentrated in a small area.

  20. John Brooks | | #20

    I think we should build Homes for our families.

    And Build Sheds for our "Stuff" and our Cars

  21. Joel Cooper | | #21

    Martin, thanks for the easy-to-understand definition for a superinsulated house. In your definition, you wrote "no bump-outs". What is your definition of a bump-out and what/why should it be avoided?

  22. GBA Editor
    Martin Holladay | | #22

    Joel,
    Examples of bump-outs: bays, ells, dormers, cantilevers, eyebrows -- you get the idea.

    Bump-outs should be avoided because they greatly increase the area of the home's thermal envelope without providing significant increases in floor area -- and therefore lose more heat in winter and gain more heat in summer. Such bump-outs (as usually detailed) also greatly increase the chances for thermal bridging and air leaks.

  23. Joel Cooper | | #23

    I had a slightly different definition of a bump-out. We would like to have a 6x10' "bump-out" on the south- east side of the building. It would take advantage of an unique outdoor setting plus provide an unique indoor space (and it would make my wife happy). It sounds like it may not exactly fit the preferred rectangular formula, but if built to the same standards as the rest of the house, would not seriously diminish the energy efficiency of the building.

  24. GBA Editor
    Martin Holladay | | #24

    Joel,
    It's your house. Go for it.

  25. Matthew Amann | | #25

    John Brooks, I loved your "fork in the road" response to Martin's excellent response.....;>)

  26. Richard Clark | | #26

    Martin, I like your basic description in entry #3/, but have to ask why no insulation under the slab? Is it not a basic starting point of a super (well) insulated house?
    Thanks

  27. Joseph Garten | | #27

    Is the cart going before the horse? The OP mentions cost several times in the original post...so the first advice I would give him is to identify a realistic budget. Once a budget is identified for the project then a discussion about the different strategies and approaches for "green" can be more on target.

    So what is the overall budget for the project? Is the land paid for? Are you going to take a loan for the construction and if so what are the current average square foot comp appraisals in the area? Does the sight require a little or a lot of sitework? Is public water and sewer available or will a well and septic system need installed? If a well is needed then do folks in the immediate area need to treat or filter their water? All these things add to the cost of the project before the house is even considered and might dictate choices for "green" details and the overall approach to the project.

  28. Lucas Durand - 7A | | #28

    Once a budget is identified for the project then a discussion about the different strategies and approaches for "green" can be more on target.

    Yes, budget is important.
    Finishing materials are part of "the budget".
    How are envelope improvements supposed to compete with the "trimmings"?

    How many production builders offer "envelope packages" in the same way that they may offer "finishing packages"?

    How is an "average" (ie: not-so-dedicated, non-forum surfing) consumer supposed to prioritise their decision making in "the budget" without having different cost scenarios to compare?

    Most consumers don't hire architects.

  29. GBA Editor
    Martin Holladay | | #29

    Richard,
    Needless to say, my short list of bullet points was never intended to be a full specification. Of course I agree with you that a superinsulated house in Pennsylvania should have insulation under the basement slab -- at least R-10, and more if there is hydronic tubing in the slab.

    Although I didn't mention it, it goes without saying that the designer and builder should have a plan to achieve airtightness goals as well.

  30. Richard Clark | | #30

    Thanks Martin.
    Is there a similar system as HERS rating for Canada. (British Columbia )

  31. GBA Editor
    Martin Holladay | | #31

    Richard,
    Yes. You can find out more from CRESNET. Here are some links:

    http://www.cresnet.ca/

    http://www.resnet.us/about/cresnet

  32. Matthew Nolette - So Maine CZ 6A | | #32

    RE Post 12 John Brooks

    Sorry to leave your question hanging for a week.

    My figures do not include the basement but my point was to encourage a smaller footprint which reduces the basement costs.

    I haven't found the double wall construction is as significant to the 1-story/2-story argument as the inevitable greater roof spans and larger foundation, ceiling, and roofing square footage that comes with doubling the volume on a single story. I treat the interior non-bearing portion of the double wall as I would an interior partition; I'm not saying it's inconsequential but relative to roof assembly it has much less impact to cost/sqft. The additional footprint needed to maintain the same interior square footage when using a 10" double wall is about 8% greater on a home measuring 28'+/- by 36'+/- and that decreases as you increase the size of the footprint. I agree with your take that the dollars spent on the ceiling plane are more effective dollars on a $/R-value basis but strictly on a labor and materials basis I find that it's less costly to add a second story for added volume. Admittedly, I don't have solid comparisons done for a monolithic slab construction (only full basement) and I suspect the differential would less.

    Matt

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |