Passive House FAQ
Due Diligence + Pre-Development FAQ
LA – Passive House is basically a building energy standard. It is the most rigorous energy standard available. However it is performance based, not prescriptive which provides flexibility in design. PH has three main thresholds which cannot be exceeded: a heating demand, a cooling demand and a whole building source energy demand all of which are measured on a per sqft basis.
KL – I’d phrase it more along the lines of: Passive House is the most reliably effective approach to designing healthy, resilient, affordable and comfortable buildings. It starts with an optimized enclosure, that crushes the heating demand by up to 90%. A fully integrated and performance based approach it’s the platform of fundamental performance metrics….
AK: Passive House is the most rigorous green building standard in the world. It focuses on insulating a building (like a thermos) to reduce heating and cooling loads and ultimately reduce energy usage and carbon emissions up to 80% compared to a standard code building.
‘Significant energy/cost savings’ as opposed to percentage amount.
LA – the costs to achieve PH depend on the developers/owners basis of design. For the majority of our PH projects we see anywhere from 0 to 7% increase with a typical average of 4%.
KL – The cost premium can vary depending on experience of the team and the extent of
AK: Multifamly high-rise construction had about a 2-5% cost premium that is inclusive of added soft costs for added inspections and consultants.
KM – I would add costs can often times be covered by energy savings. Differentiating between hard and soft costs. Potential foot note referencing case studies, where available. Does Bronwyn’s policy doc have good reference points? Increased availability of materials bringing down costs. Varies widely, a repeat team had proven to reduce costs over time. Will hopefully continue to reduce overtime as technology improves, as well as the availability of materials increase.
AK: Resillience and carbon neutrality have increasingly become significant criteria to evaluate in the investment space. We do not yet know how to “value” this component of buildings, but we do know that exit values can be heavily influenced by the increased costs of not including energy reduction measures in existing buildings. Investors have begun to rely heavily on various benchmarking standards that take environmental impact of the assets into consideration. One of the most relied upon standards is GRESB – the Global Real Estate Sustainability Benchmark which ranks/scores Passive House.
‘Future proofing’ – resiliency of a building could impact value, especially as it relates to climate change and every policy. For example LL 97 compliance. Sustainable way to build.
AK: I don’t think we have the data but we should discuss whether the data has evolved.
Operations – YES. 40-50% improvement. Maintenance – potentially pay more for operational staff. More difficult to quantify. More hands on from asset management and maintenance perspective, inclusive of a training component. Training is required. Break out M from O. Bright power white paper? BE-EX website? However cost of not implementing passive house could be more expensive – less likely to have decay, moisture, mold, issues, with improved durability. However from a systems maintenance aspect, it can be more intensive. Johnathon Rose/L&M info?
LA – If your tenants pay for their heating and cooling, they should see a significant reduction in their utility costs.
AK: Advertising and marketing of lower utility bills should be based on data and evidence. We strongly encourage that Property Management companies gather and track individual tenant utility data to ensure that the Passive House program is effectively reducing usage.
KL – do we have access to this data from CPC/HPD/NYSERDA or from others? Does Cornell have hard numbers we can reference? Carrick Library?
AK: Something about having an ongoing benchmarking and monitoring system – requiring a BMS?
KL – Success can be assessed quantitatively & qualitatively. The simplest measures are the total annual utility usage and how it compares to the design’s calculated predicted performance. Data can be measured more granularly from individual “spot” sensors to comprehensive BMS systems, for not just energy but for indoor air quality too. Qualitatively, occupants should feel thermal comfort and stable temperatures without drafts, with fresh air and related reductions in illness. It should be acoustically separate from outdoor noise, with quiet internal mechanical systems. It should feel peaceful.
LA -Yes, PH actually requires operable windows in all living spaces. In addition to that, all PH projects require fresh, filtered air be delivered to all habitable spaces 24 hours a day, 7 days a week.
KL – Natural ventilation is a core Passive House strategy and is encourage as part of the building design. However, because natural ventilation cannot be relied upon, Passive House provides high-qulity filtered fresh air mechanical ventilation for all occupied spaces, that can, and often does, operate 24/7.
Sustainable way to build.
LA -ERV filters need to be changed at least twice a year. On small, unitized ERVs, the intake air grill should be accessible as it will need to be cleaned occasionally as well.
AK: I think we should address refrigerant line leaks and potentially extra training for building managers. SInce the systems have refrigerant in them, it can be hard to identify leaks so the line charge should be checked on annual basis (VRF specific). Also let’s add in that a multitude of heating and cooling systems can be used so if you are more comfortable with a non-VRF system than PH is still feasible.