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Old 12-16-14, 02:36 PM   #21
Ormston
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The passive haus requirements do seem a bit strange, very tight heating/cooling limits but sloppy overall consumption limit.
We are well within the 120kwh/yr/m2 (around 70) and not far off the 15kwh/yr/m2 heating but our house is nowhere near PH standards in window or wall U values.

I remember some time ago reading there is a correction factor in the passive haus standard for climate, but have never been able to find any other reference or details on this. Anyone?

Also not too sure about how the heating requirement is implemented with regard to heat pumps? Is it just power from the grid that counts or heat pump output?

Steve

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Old 12-17-14, 06:35 PM   #22
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The passive haus requirements do seem a bit strange, very tight heating/cooling limits but sloppy overall consumption limit.
We are well within the 120kwh/yr/m2 (around 70) and not far off the 15kwh/yr/m2 heating but our house is nowhere near PH standards in window or wall U values.
How many square meters is your house?

-AC
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Old 12-17-14, 06:52 PM   #23
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I remember some time ago reading there is a correction factor in the passive haus standard for climate, but have never been able to find any other reference or details on this. Anyone?
The Passive House Planning Package does have localized information for the locale where the proposed Passive Haus is to be built.

It also has significant sections where fenestration losses and solar gain can be calculated.

These sections would allow the designer to compensate the design for unusual occurrences such as a large evergreen tree on the sun side.

-AC
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Old 12-18-14, 01:55 AM   #24
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How many square meters is your house?

-AC
90m2 currently lived in but open to the attic which is mid conversion and not fully insulated yet so we are heating around 135m2.

My question with the passive haus localisation is how is this applied, as in do you get a larger heating budget in colder climates of do you have to add more insulation to keep within the 15/25 kWh/m2/yr making the PH standard easier to reach in some areas than others?

Also since the 120kwh/m2/yr appears to be generous with modern appliances, simply changing all my cfl and led lamps back to tungsten or halogen lamps and maybe swapping LCD TV,s for plasma would still keep me within the 120kwh and provide most of the heating load making the 15kwh limit redundant?

Steve

Last edited by Ormston; 12-18-14 at 02:34 AM.. Reason: typo and more ramblings
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Old 12-18-14, 05:52 AM   #25
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It is my understanding that the required heat losses are fixed. If it is a colder climate, you have to do more to meet the requirements. I could easily be proven wrong on this, though.

I have to get into the regs more deeply and see what they mean. Unfortunately, there are 50 other projects on my plate, haha, including 3 unfinished HPs
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Old 02-16-15, 03:58 PM   #26
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Haven't caught on to the attraction of the PassivHaus standard myself. The standard I want my home to meet is the most sustainable energy required to keep me the most comfortable at the most affordable cost with the least amount of my personal leisure time needed to maintain it. All the passive house homes I have toured, though impressive, have all been far outside "affordable" housing prices. When they include a realistic "cost factor" in the standard it might have some worldwide value IMO.
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Old 02-16-15, 07:52 PM   #27
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When they include a realistic "cost factor" in the standard it might have some worldwide value IMO.
Here is the CONTACT_PAGE for The International Passive House Association.

I'm sure they would like to hear what you have to say.

-AC
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Old 02-16-15, 09:40 PM   #28
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The theory with a passive house is Pay now save later

With ingenuity or the right plan it can be done on the somewhat cheap. My brother in law built a straw bail house with a turf roof heated by a large Rocket stove built from stone and cement in the center of the house.
He lights the stove twice in 24 hrs and lets each fire be started and burn itself out which heats the massive rocket stoves stone work and releases it threw out the day.

I like the idea of expending all your resources at build time so when the build is completed you are not throwing your money down the toilet paying electric and fuel bills.

Instead your money is invested in the house.
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Old 02-18-15, 02:34 PM   #29
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Haven't caught on to the attraction of the PassivHaus standard myself. The standard I want my home to meet is the most sustainable energy required to keep me the most comfortable at the most affordable cost with the least amount of my personal leisure time needed to maintain it. All the passive house homes I have toured, though impressive, have all been far outside "affordable" housing prices. When they include a realistic "cost factor" in the standard it might have some worldwide value IMO.
The Passivhaus standard for primary heating load is based on trying to make things passive and cost effective for Germany. ..and it is. It's also far more expensive to build the common heating system in Germany, hydronic heating, versus the typical cheaper to install forced air heating in the US so that is a factor to consider, they skip the hydronics and save a bunch and oddly enough the heat that is needed in the Passivhaus and other low energy buildings I've seen in this area have all been forced air in some fashion or another except for the Habitat for Huamanity house that has multiple wall mount 1kw plate-type resistance heaters. The odd thing is that mini-split heat pumps generally always seem to be added later for air conditioning needs due to not realizing the consequences of overglazing. I spoke with the owner and told him to use the mini-splits unless they really can't produce the heat needed.

The fun thing about Passivhaus is there is a recommendation on peak heat load but isn't one for cooling loads, that just gets lumped into the primary energy usage. ..why not just let the builder decide the heat load needed to get to the primary energy usage target. There's also the part about the 0.6ach50 requirement was set for dealing with condensation more than energy. It's later been determined by others that 2ach50 is plenty good for reducing condensation risk.

The cost effectiveness of following Passivhaus to the letter to get certified in Minnesota might not be worth doing, especially for people holding a 30 year mortgage to do it. I think the R60 roof versus an R120 roof, R40 above grade walls instead of R60-80 walls, R10 sub-slab instead of R30+(seriously?), R5(u.2) windows is plenty fine for our climate.

My personal goals for my retrofit are about R80 roof via 1000 pounds of cellulose added to the current R25. Walls add 4" of XPS to the existing R13 batts and 3/4" polyiso wrap. I'm finished with my work on air sealing although a B-vent stack going out the roof might take awhile to go away depending on how long the water heater lasts and I'm having issues with considering the expensive of replacing a working gas furnace with a condensing one considering my methane bill for January was 39 therms, $41. Windows are expensive and will come last. This will be expensive to do on a 2100sq ft house but I think those figures for target R values make sense.
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Old 02-18-15, 03:53 PM   #30
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ecomod, anyone adventurous enough to build and heat as your brother-in-law I doubt is doing so to try to achieve an arbitrary standard of certification(because years from now homes may be insulated into the R100's). He appears more interested in the most he can get himself for the best cost. MN Ren, If all that non breathable insulation is planned to be installed outside the existing R13 and is R26 or more you will inviting serious moisture condensation problems inside walls. No more than about 1/3 of the total wall R value should be inside the vapor barrier so vapor moisture will not condense out. And I agree with you that there are many things one can always do to improve efficiency but they should be netted out with what they will truly save you. Investing big in paybacks that could take 20 or 30 years seems pretty risky to me. I'd rather take smaller savings now and be free to change to newer innovations. I'm only feeling OK with a "poured in stone" radiant floor(that is forever) because it is also time proven thermal mass for passive solar and how to provide hot fluid for it is adaptable.

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