Prudence Ferreira – Passive Design, Building Science and Creating Resilient Housing


Episode 379. Kathleen interviews Prudence Ferreira about the power of design and engineering to solve some of our country’s biggest housing and energy issues. Prudence serves on the PHIUS Board of Directors where she was previously president. She has consulted on over 30 passive design projects across seven different climate zones.


Host: Kathleen Slattery-Moschkau


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00:30 Passive design definition

00:35 A climate specific, cost optimized set of building science principles

00:55 A logical pathway to Net Zero

01:20 What constitutes passive design

2:45 Building as assets vs liabilities

04:25 Continuous insulation

04:35 Avoidance of thermal bridging

05:35 Energy recovery ventilation

05:50 Air sealing

09:36 It comes down to how we design and construct the building

10:10 Maintain comfortable temperatures reagardless what is going on outside in terms of extreme temps

10:35 Allows our homes to protect and shelter us regardless of what happens to the grid

11:45  It’s about paying amazing attention to design and then construction execution

12:41 Cost differentials to build with passive design methods

14:22 Scale – large projects like multifamily and dorms, drives down the costs and may even not add to the cost at all because of savings in other areas like mechanicals

14:30 Passive design certification

15:30 Scale and costs further explained

19:00 Large scale at a 1% cost premium for passive design, setting up a pathway to net zero buildings.

19:40 We have the technology, we have the building science know how to do net zero energy buildings that don’t cost any more than conventional buildigs

21:00 Less reliant on heating and cooling needs, thus financial savings once the building is operating

21:25 What kinds of energy reductions do we see with passive design and how does that equate to operating cost differentials?

23:15 Greatly reduced utility bills due to energy preservation. In a cold climate, the buildings heat themselves

23:35 Use and contain the heat thrown off from people, appliances, etc.

24:00 Not wasting any useful internal gains

24:15 How do energy reductions in passive design compare to conventional construction and other certifications like LEED

26:45 PHIUS – Sets passive house standards for North America

27:30 Climate specific passive house vs German passive house methods which are one size fits all

28:00 Why have we been slower in the United States to adopt this very basic, solid engineering approach?

30:40 The politics of energy. Not a left vs right thing, just solid engineering and building design.

34:00 Passive design and self reliance

34:30 Not dependent on the grid, energy independent

35:30 Not a political issue, an engineering issue. Engineering is above politics

36:00 Other barriers to passive design

36:15 Public misperception is that passive design is aesthetically unattractive. How do we overcome that barrier?

37:00 Early adopters, lessons learned.

37:30 Trump speech on passive house

38:00 Passive house can look like anything you want.

38:15 Passive house branding, and the word passive does not connect with people.

40:30 ‘Resilient’ as a better word than passive?

41:45 Passive design as a matter of national security.

42:30 The fragility and aging of our grid.

43:15 The Department of Defense,  the Army Core of Engineers, Armed Forces

44:00 The state of Massachusetts, building code

44:15 Once local contractors have experience, things snowball

45:15 Train the trades

47:10 Once they go passive, they don’t go back

47:15 The builder gets to bring back a nobility to the trade.

47:30 Builders make a massive difference to the process

48:30 That contagious excitement and pride is contagious.

49:00 A noble, honorable trade

49:20 Experience as a solution

50:10 Personal journey

53:30 Thornton Tomasetti  

58:20 Book Recommendation: Transforming Design and Construction