“I grew up in Colorado in an early version of a Passive House designed in the 1970s. It was super-insulated, had natural ventilation, and utilized active and passive solar radiation strategies. I went to architecture school at the University of Colorado–Boulder, where the architecture studios were taught around a passive design bent. So, as a firm, from the very beginning [in 2004], we have always dealt with how to reduce energy consumption as much as possible.
The H2O Apartments was our first [time also acting] as the developer. Being our own client, we had the freedom to set design priorities and test energy-use optimization strategies. We started by eliminating systems in order to achieve better energy performance. The project is a 39,000-square-foot, seven-story, multifamily live-work project. Usually, in these kinds of buildings, the lighting, heating and cooling, and pressurization of the corridors draw a lot of energy because the systems are operating 24/7 for the life of the building. So, we moved all of the corridors and stairs to the exterior of the building and turned them into a system of walkways instead. With one move, the building performance was much improved.
Moving the corridors to the exterior of the building also allowed better light and better natural ventilation into the units. H2O doesn’t have a core, so all units receive natural light on two sides. Not only does this improve daylighting performance, but it allows for natural breezes and cross-ventilation throughout the year, especially since Seattle does not experience too many high-heat days. There is no air-conditioning system on the property, period.
Each unit also exists as its own atmospherically separate unit to help meet thermal performance goals. We knew as we were designing the building that our weakness was going to be air infiltration through electrical outlets. We used putty packs that are found in firewalls, packing them around the backs of the each electrical outlet box to keep the air in each unit isolated. [This] improved acoustics and the transfer of odors too. This is important in a multifamily building. At H2O, you will never hear your neighbors, and you won’t smell their cooking.
The building has many other features taken from Passive House principles—high-quality triple glazing on its north façade and double glazing for the rest of the building; durable, long-term materials that have a lifespan of up to 150 years; and a hybrid wood-concrete structure that acts as a carbon sink. And its design unites all systems so there is no performance ambiguity.
It took some extra work to get the City [of Seattle] onboard, but H2O Apartments has been a very successful project. It helped our firm learn how to approach and develop systems for high-performance, larger-scale projects. We took those lessons and folded them back into our other work, and they are now baked into our standard approach.”