THE FUTURE OF SYSTEMS
Future homeowners will live in a world where rising codes and standards have made homes 30% to 50% more efficient than today. Energy Star Version 3 will be more than a decade old. Expectations for comfort, performance, and health will be higher. There will be more builders catering to the high-performance home market.
Then there are the homes themselves. We know heating and cooling loads will continue to drop. And no matter how high-tech they get, traditional ducted HVAC systems will inevitably become less effective at providing ventilation, humidity control, and filtration. With lower loads, less and less air will pass through the system. That small volume of air won’t be enough to maintain the right level of moisture and air quality considering the large volume of air in the house. It will become more efficient to condition the air in rooms, rather than moving conditioned air to rooms.
While heating and cooling loads drop, the quantity of air needed for ventilation will rise proportionally. Since the air inside can be 10 times worse than outdoor air, indoor air quality will become an even bigger concern.
One thing that seems clear is a trend toward fewer, smaller, or even no ducts in heating and cooling, since ductwork can add up to 30% to the energy consumption of space conditioning. One candidate to replace the traditional ducted, forced-air system is some version of a ductless mini-split air source heat pump. These mini-splits will supply cooled or heated air to individual rooms or groups of rooms. People will be able to condition only the rooms they’re using. And they’ll have more control over their comfort, setting the conditions that are right for the area or even the individual.
We’ve also been assessing even more radical solutions for high-performance homes such as single- or dual-point heating and cooling, with distribution either partly or completely handled by air currents, transfer grilles, and conduction through walls. We are even experimenting with low-cost ways to move air into closed-door bedrooms via computer fans in overdoor transfer grilles.
Ventilation will include air purification, so that indoor air quality is enhanced along with spaces being properly ventilated, and it will probably need to work toward moisture removal as well. Another possibility is that loads will be so low that some version of a heat or energy recovery ventilator will also handle heating and cooling, with an air purifier either separate or integrated into the system.
Whatever kind of equipment comes to dominate the HVAC market, it will likely incorporate a home energy management system (HEMS). Although several companies currently offer HEMSs, no system has caught on widely or integrated all the functions homeowners will need and want. We predict that future HEMSs will be able to monitor and control indoor air quality and moisture in tandem with ventilation and heating/cooling systems, and they will also be able to monitor occupancy, energy use, and even energy generation and storage, in an intelligent way. These systems will give homeowners total comfort, control, and insight into how their home is performing.
CHALLENGES AND OPPORTUNITIES
At IBACOS, we’re optimistic, but we’re also practical. Beyond technology and design, there are other issues that have to be addressed in order to make consistent delivery of high-performance homes possible at the industry level:
Stressing building science in education. Building science is the key to understanding how the building enclosure, the HVAC system, and every other part of a home work together as a system, but designers, architects, and engineers aren’t encouraged to be forward-looking. Building science is critical to the future of this industry. It needs to be part of the curriculum for anyone working in this industry, starting now.
Creating a mind shift with key stakeholders. Another issue is that equipment manufacturers, trade contractors, code bodies, and officials all have a vested interest in the status quo. As we’ve seen, whether it’s in building systems or business processes, the approaches that are likely to be most effective are also very different from the current ones. In space conditioning systems, for example, a new kind of system would be much more comfortable and economical for homeowners to operate, but manufacturers would need to reorient huge portions of their businesses in order to develop, manufacture, and market them on a large scale. Trade contractors would also have to learn a whole new bag of tricks and get used to the idea of less expensive equipment, faster installations, and lower overall income per installation. Code officials would need to better understand how high-performance building practices impact codes.
Incorporating performance in green building programs. Also, despite all they have done to raise awareness about the importance of environmentally friendly, high-performance design, green building standards and rating systems present their own obstacles. For example, from a building science perspective, LEED is somewhat flawed in its focus on building design rather than building performance, and the way certain features of that design are weighted. Green building standards also don’t always track building performance or keep track of energy bills versus projected savings, making their claims hard to prove. As yet there is no consistent body of data against which to measure how these buildings are performing versus their projections. For these standards to be truly effective, they have to meet the standards of building science, which are measurable and verifiable results.