We were told not to bother with the passive house standard because we were building a small home in a cold climate and it would be impossible to meet the certification.
Well, in March of 2015, the standards changed. There's now a chance we would meet the new standards for our climate zone with a small structure. Read more here: http://www.phius.org/phius-2015-new-passive-building-standard-summary
1. The air-tightness requirement was reconsidered on the basis of avoiding moisture and mold risk, using dynamic hygrothermal simulations to be published elsewhere. The change is from a limit of 0.6 ACH50 to 0.05 CFM50 and 0.08 CFM75 per square foot of gross envelope area.
We calculated our goal as follows:
.05* Gross Envelope of 1152 (42+24)*2*9) = 57.6 CFM50
Translation to ACH50:
57.6CFM*60 = 3456 CFHour
3456/ house interior cubic feet of 7524 (22*38*9) = 0.46 ACH50
2. The source energy limit is now 6200kwh/person/year, so we have 12400kwh as a limit. It may go back to 4200kwh/person in the future. We use approximately 500kwh/month when we are home for the summer. This leaves us 9400kwh/year to use for the heat in the building. Should be very simple to meet that given our design approach. Also, installing the solar panels will be considered toward the source energy limit.
3. Space Conditioning Criteria: The standards have changed in 2015 – in theory helping a small house to meet the metrics. The new standards for Atikin MN are:
For us, iCFA is calculated as 22 * 38 = 836.
Well, in March of 2015, the standards changed. There's now a chance we would meet the new standards for our climate zone with a small structure. Read more here: http://www.phius.org/phius-2015-new-passive-building-standard-summary
1. The air-tightness requirement was reconsidered on the basis of avoiding moisture and mold risk, using dynamic hygrothermal simulations to be published elsewhere. The change is from a limit of 0.6 ACH50 to 0.05 CFM50 and 0.08 CFM75 per square foot of gross envelope area.
We calculated our goal as follows:
.05* Gross Envelope of 1152 (42+24)*2*9) = 57.6 CFM50
Translation to ACH50:
57.6CFM*60 = 3456 CFHour
3456/ house interior cubic feet of 7524 (22*38*9) = 0.46 ACH50
2. The source energy limit is now 6200kwh/person/year, so we have 12400kwh as a limit. It may go back to 4200kwh/person in the future. We use approximately 500kwh/month when we are home for the summer. This leaves us 9400kwh/year to use for the heat in the building. Should be very simple to meet that given our design approach. Also, installing the solar panels will be considered toward the source energy limit.
3. Space Conditioning Criteria: The standards have changed in 2015 – in theory helping a small house to meet the metrics. The new standards for Atikin MN are:
| Zone 7 | Standard | Our House |
| Annual Heating Demand kBtu/sf-iCFA.yr | 8.6 | 7189600 |
| Annual Cooling Demand kBtu/sf-iCFA.yr | 1.3 | 1086800 |
| Peak Heating Load Btu/sf-iCFA.h | 4.8 | 4013 |
| Peak Cooling Load Btu/sf-iCFA.h | 3.9 | 3260 |
| Manual J Peak Heating Load Btu/sf-iCFA.h | 7.9 | 6604 |
| Manual J Peak Cooling Load Btu/sf-iCFA.h | 5.5 | 4598 |
For us, iCFA is calculated as 22 * 38 = 836.
There's a lot more information on why the standards are changed in the paper that was published on the research:
http://www.buildingscience.com/documents/bareports/ba-1405-draft-climate-specific-passive-building-standards
In addition, there's a free version of the WUFI software:
http://wufi.de/en/service/free-wufi-versions/