First of all I would advise you not to build on top of a garage if you can avoid it. This is because attached garages are a major source of pollution in homes. In the winter the stack effect inside an above garage apartment will pump pollutants into the living space. These pollutants are put out by vehicles (and gas powered equipment) even when they aren't running. The major source (when not running) is the gas tank but also pollutants come from the crankcase, tires, interiors, etc... The way to combat this is properly sizing continuous negative pressure ventilation of the garage space. There is no consensus on the correct rate. To find out the correct rate you must get a manometer reading while you negatively pressurize the garage and ensure the air pressure is lower at the adjoining plane (wall and/or ceiling) inside the garage compared to inside the living space, while the living space is operating at max likely negative pressure (in your case likely with the kitchen hood running on high and the bath fan on).
As for HRV/ERV the Panasonic intelli-balance is likely the most economical choice, but Zehnder makes an excellent unit with unrivaled efficiency. You may also consider doing away with an HRV/ERV entirely and doing a supply ventilation strategy. This could be a good thing for you as it will help keep the living space at a higher air pressure than the garage.
As for mini-split use whatever your local knowledge base is comfortable with. Both Mitsubishi and Fujitsu tend to have good regional representation, but local knowledge can still be spotty. Both of those companies also have units that work until around your design temperature so baseboard heat may not be needed.
|