House blog & pics
I've kept a blog running during construction:
vinnie
Picasa albums with construction pics:
Picasa Web Albums - mrd999 - vinnie pics b...
Picasa Web Albums - mrd999 - vinnie pics b...
Heat pump selection
During the home design process, I read about these inverter heat pump systems and wanted to determine if it would be feasible to use one. There are a few traditional-type split systems on the market with inverter compressors - I believe they're called 'IQ Drive' - but from what I've read the equipment is expensive.
I ran Manual-J load calculations using
Rhvac. From this I ascertained a cooling load around 11kbtu and heating load around 19kbtu. A 1.5 to 2 ton system would meet this.
To be fair, 2 tons (24kbtu) is oversized for a 11kbtu cooling load. But I assume with the inverter systems' ability to ramp down compressor speed, it will comfortably handle a 50% design load. It's not ideal, but it allows me to use a single heat pump to meet cooling & heating design loads. If I were using a traditional fixed speed heat pump, I'd likely order a 1.5 ton heat pump with supplemental heat - propane perhaps, as natural gas isn't available here.
That fact was a factor in my selection of this equipment. It's illegal in Delaware to perform any gas piping without a plumber's license, even on your own home. As I'm doing all the work on this home myself, I wanted to forgo the need to contract a licensed plumber. Staying with an all-electric system allowed this, and the inverter system made it practical to go this route.
Most of the inverter systems found in the market here have a single indoor unit, and they are wall-mounted. However there are also multizone systems with multiple indoor units connected to an outdoor unit. There are also various types of indoor units available aside from wall-mounted units. One type is a ductable blower.
I am using ducted indoor units because I want the HVAC system installation to give the appearance and function of a typical system found around here, which is ducted with registers throughout the home delivering conditioned air. I'm mounting the blowers in the conditioned crawlspace and running ductwork to registers.
The Fujitsu system I selected is called "ceiling concealed" and is meant to be installed in the ceiling, typically above a drop ceiling in a light commercial environment. It has a small blower and is optionally ducted. However, after looking at the heat & fan specs, I determined it would suit my needs. There are other blower units available from other manufacturers with a stronger blower actually designed for the type of install I'm doing, but the closest in price to this unit I found was about $700 more. This seemed the best bang for the buck.