How large is the outdoor unit?

The size of the outdoor unit varies by the size (BTU rating) of the outdoor unit, and the brand. In general, a Fujitsu single unit is about 34" wide and 24 1/2" high, and a Mitsubishi single unit is about 33" wide and about  34 1/2" high. A Fujitsu multi outdoor unit is generally between 35 1/2" and 38 1/4" wide, and 28" and 39 1/2" high; a Mitsubishi multi outdoor unit is generally between 37 1/2" and 41 1/2" wide, and between 41 1/4" and 53" high. Ask your designer for the specific dimensions of your particular unit if this is important to you. 

What do you mean by a "single" heat pump? a "multi" heat pump?

A single heat pump means that you have a "single" system: one outdoor unit paired with one indoor unit. You can have more than one "single" heat pumps. A "multi" heat pump means one outdoor unit connected to more than one indoor heat pump. You can have multiple "multi" units, multiple "single" units, and of course a combination of "single" and "multi" heat pumps. 

What brands does Goggin Energy sell?

Unlike many of our competitors, we source several brands. That is because your situation might require a certain solution, and one of those brands might be better for that solution. We currently sell Fujitsu, MItsubishi, and Daikin, as we believe that those brands offer the best combination of output and low heat temperatures. More brands are hopping on the heat pump brand wagon and we evaluate those as they come out.

Do heat pumps stop working when it gets cold?

Most of the heat pumps that we sell put out 100% of their capacity at +5F, and are rated to to -15F. Every heat pump has a "low temperature" rating.  The heat pump won't actually stop working at this temperature, but the amount of heat put out below this goes down significantly and the amount of electricity needed to run the heat pump goes up, so for all practical purposes assume that they don't work below this temperature. 

Can I install one indoor unit now and add another unit later?

Yes, but there are some limitations. Multis require at least two connected indoor units of specific size in order to function. So, within allowable size ranges, you can start with two indoor units and add more later to the same outdoor unit. If you want to start with just 1 indoor unit, you will need to install a single system, and add a new outdoor unit for any future additions.

What do HSPF, COP and SEER mean?

HSPF = Heating Season Performance Factor. This is a term used to measure the efficiency of air source heat pumps.  The efficiency is measured over an average heating season. HSPF is a ratio of BTU heat output to watt hours of electricity used. It has units of BTU/watt-hour.  The higher the rating, the more efficient the unit.

SEER = Seasonal Energy Efficiency Ratio. This is a measure of a heat pump's efficiency over an average cooling season, using cooling output in BTUs compared to electricity consumed in watt-hours.

COP = Coefficient of Performance. This is the ratio of cooling or heating output to energy consumed at a specific temperature. This ratio converts both output and consumption to a common unit, making this different than HSPF or SEER which use a ratio of BTUs to watt-hours. The higher the COP, the better.