Historically and currently, Heating, Ventilating, and Air Conditioning (HVAC) companies oversize heating and cooling systems for residences. Conventional forced hot air systems continue to be the most commonly installed systems, and this has been the case for the last few decades. However, in just the last several years, homes have become much more air-tight as new codes move everyone in the “Build it Tight and Ventilate Right” direction. Essentially, the HVAC industry is slow to catch up with the fact that homes have much lower heating and cooling loads than they did just five and certainly ten years ago. The “big-old” off and on systems are oversized, often uncomfortable, and becoming outdated.

Meanwhile, air-source heat pump technology has advanced such that it works well in cold climates. This relatively new capability combined with homes that have much lower heating and cooling loads has created a great opportunity for these systems to be installed in new code-built homes. No longer do homes have to have fossil-fuel fired furnaces (or boilers) that turn off and on and are controlled by just a couple or few thermostats. Homes can now be heated and cooled cost-effectively with properly sized air-source heat pump systems that run continuously and allow for multiple zones.

The way air-source heat pumps work requires a paradigm shift in how we see our homes being heated and cooled. Air-source heat pumps are essentially air conditioners that work both ways transferring heat outdoors in the summer and transferring heat indoors even on a cold winter day. When properly installed, an air-source heat pump can deliver one-and-a-half to three times more heat energy to a home than the electrical energy it consumes. This is possible because a heat pump moves heat rather than converting it from a fuel like combustion heating systems do. This makes them cost-effective to operate over long period of time to produce a more consistently comfortable indoor environment.

Designing and installing air source heat pump systems for new homes is not rocket science, but it does require knowledge of building science as well as an understanding of the technology and how it works to provide continuously effective heating and cooling. Many systems are simply oversized for homes and for the rooms in which they are installed. This results in uncomfortable conditions and unnecessarily higher operating costs.

The first step in designing a system is do a Manual J heating and cooling load calculation for a home. This is done on a room by room basis and must be done using Air Conditioning Contractors of America (ACCA) methods. Once a Manual J report is complete, the process of designing a system can begin.

Designing a system can be easy with smaller, open concept homes or it can be challenging with more complicated home designs and larger homes. Heat pump manufacturers such as Mitsubishi Electric have developed a range of indoor components that can be adapted to fit a home’s needs. Heat pump designs can be all ductless, meaning only refrigerant lines running inside and out, or ducted. Typically, a combination of ducted and ductless heat pumps makes for a good application. The ducted system can supply smaller bedrooms and bathrooms while the ductless indoor units supply large open areas such as dining rooms and living areas.
Air-source heat pump technology is a big component of new “Smart Homes”. These are homes that can be made more comfortable on a room by room basis which is a major step in increased comfort and efficiency. Each indoor unit or zone and be controlled remotely from a cell phone.

In summary, improved technology, more energy efficient homes, significant financial incentives, and a big step up in comfort have made air-source heat pumps very desirable. As energy geeks, we see the advantages, and this is why we design, install, and service air-source heat pumps. We are very excited about the current synergy that exists and the future.