An example of a recent (2009) renovation designed to meet the Passive House energy standard, using a phased approach. (And yes, the air-tightness standard is possible on a retrofit!)
The Larkspur Remodel: A Phased Approach to the Passive House Standard
1.
2. Who we are: A DESIGN BUILD COMPANY + PRODUCT DISTRIBUTOR, PERFORMANCE TESTER and ENERGY ANALYST
3. What do we do? We DESIGN + BUILD Q+ homes that can PRODUCE MORE ENERGY than they consume. We have committed to build all our NEW PROJECTS so that their building ENVELOPE meets the PASSIVE HOUSE STANDARD
24. Testing, testing… Source: Sustainable Spaces GreenUP report for client, 2007, & PHPP 0.54 8.20 PHPP (ach/hr n50) 22 196 Equiv. Hole (sq inches) 227 3469 CFM50 After Before AIR LEAKAGE
25. Previous energy cost: Source: Sustainable Spaces GreenUP report for client, 2007 EXISTING (kWh/sf,yr) Elec: 4.46 Gas: 8.08 Total: 12.54
26. Where the losses were: Source: Sustainable Spaces GreenUP report for client, 2007
27. Projected energy use: Source: Sustainable Spaces GreenUP report for client, 2007 Note: The projected energy use assumes final PH compliance. It has been modified for variance between PHPP TFA and typical overall sf energy use calculations. Benefit of the Solar PV system is not included. However, since we did not install the slab insulation, it will likely be higher.
28. Compared to others: Source: PG&E & Sustainable Spaces GreenUP report for client, 2007, & PHPP
34. Thank you from the Team: Architect: Josh Moore Project Manager : Carlos Velasquez Crew: Attu Fave Paea Favaleaki Peter Soruco Testing: Stefan Carpentier Energy Analysis: Mary Graham Bronwyn Barry
Notes de l'éditeur
Roxul Top Rock MD rigid mineral wool was used on the exterior walls. We also wrapped the insulation at the jambs and headers of the windows to improve the window performance.
We elected to cover the existing T&G roof sheathing with an additional skin of OSB as this was easier to air-seal. 30lb Roofing felt was then placed over the OSB and API Kingspan metal SIPS insulation and roofing panels were used as both insulation and roofing finish surface.
Perimeter insulation product: Energy Edge. (Plastic cover over 2” Expanded Polystyerene.) The taped seam on the corner is part of the Sto Gold mastic we used for our wall sheathing air-tightness layer, under the Mineral Wool exterior insulation.
Three weeks of continuous air-testing and envelope tightening yielded results! We waiting to finish our air-sealing before we installed the exterior insulation and siding.
Note: The projected energy consumption is based on final Passive House Certification compliance. Since we did not install the basement above-floor insulation, the actual number is expected to be higher than the projected numbers shown. The projected number does not take the solar PV credits into account either, so it could potentially be lower.
Client has a pool and a hot-tub!!
Biggest surprise for us here was the Thermal Bridge losses at both the roof to wall junction and the foundation to wall junction: 30% overall! These are two details that can be completely designed OUT of new construction. Seems like a no-brainer to do so…
Cost numbers were around $110/sf for this remodel. We still haven’t parsed out what percentage of that was to get it to meet the PH standard. We’re estimating that a new roof, new windows and new siding would have cost this client around $90/sf. We have buried 4 data loggers inside this project and will be retrieving them after a year. We placed one inside the house, one outside directly near the interior sensor, and two are buried within the walls on the interior and exterior sides of the old exterior siding.