Choosing the Right HVAC System

All-too-many people focus on the heating and cooling system (HVAC) without putting first things first. We’d like to believe that we kept things in their proper order by first addressing the building envelope before deciding on the proper unit.

We had originally hoped to install a geothermal system to establish lifetime low maintenance and operating costs. However, our small lot, steep slopes and heavy tree canopy all served to thwart horizontal fields for necessary underground coils. The option to drill wells for coils proved cost prohibitive. Therefore, we turned our attention to creating the best overall fit for our site.

Calculating – Not Guessing – About Unit Size
With proper framing techniques, the best insulation and top-of-the-line windows – “Creating an Energy Efficient Envelope” – we then turned our attention to the proper HVAC system. We opted for all-electric split-system heat pump (even before the run-up in natural gas prices in the winter of 05/06) because all other appliances and our on-demand water heater would be electric. Our electrical engineering and construction advisors completed a “Manual J” (Air Conditioning Contractors Association of America) calculation to determine need. As a result, and with a zone control, we were able to go with a single three-ton HVAC system versus traditional recommendations for two two-and-one-half ton units of cooling capacity.

Amana – The Right Choice
We opted for Amana – one of the best known names in HVAC – now owned by Goodman Manufacturing (http://www.goodmanmfg.com/). We looked first at the then-current code requirements for a 10-SEER (Standard Energy Efficiency Ratio) system. With units now being manufactured with SEER ratings of 18 or more, we scoped the spectrum of efficency versus cost and arrived at a 14-SEER as the optimum decision. As the project took six months longer than originally planned, code requirements as of January 2006 required 13-SEER systems. Thus, our original plan still proved appropriate. The 14-SEER Amana also has an ultra-high rating for heating capacity of 8.5 HSPF (Heating Seasonal Performance Rating). HSPF ratings range from 7.0-9.4.

Easy Facts
For a great resource on how to go about choosing the right HVAC for your project, see http://www.southface.org/web/resources&services/publications/factsheets/1heat_cool.pdf