I Have Strong Feelings About Air Conditioning in the Tech House

Choosing the System [00:00:15]

• The lack of insulation in the tech house makes traditional cooling insufficient for rising summer temperatures.
• Retrofitting a ducted forced-air system would require extensive, costly ductwork insulation and expansion.
• A mini-split heat pump was selected to provide efficient, per-zone heating and cooling without the need for complex ducting.

• With that in mind, there's a couple different ways that we can tackle heating and cooling for the tech house.

Understanding Inverter Technology [00:02:15]

• Inverter-style evaporators adjust output dynamically rather than running at 100% capacity and cycling off.
• This continuous, lower-output operation improves humidity removal, which is critical for comfort.
• The system handles varying thermal loads from occupants and sunlight exposure more effectively than traditional units.

• Instead, they're gonna run at a more limited output for longer periods of time, which is gonna allow them to pull more of the humidity out of the air.

Installation and Plumbing Risks [00:03:15]

• Ceiling cassettes must be installed with careful attention to condensation drainage to prevent water damage to the home.
• Proper mounting requires aligning units with standard North American ceiling joist spacing.
• The installation process is accessible to handy DIYers, though professional oversight for refrigerant charging is recommended.

• So much that the unit that I installed at my house with Brian the electrician back in the day ended up exposing a leak in my plumbing that I didn't know was there.

Refrigerant Line Preparation [00:07:30]

• Lines must be kept free of moisture, as water cannot be compressed and damages the compressor.
• Pre-charged inert nitrogen gas serves as a protective barrier during the installation process.
• Precision is required when cutting and flaring copper lines to ensure a leak-proof seal at the fittings.

• Any moisture in a refrigeration system is bad. Water cannot be compressed and it is not kind to compressors.

The Outdoor Unit and Heat Pump Mechanics [00:11:00]

• The outdoor condenser uses electronic expansion valves to regulate refrigerant flow to each of the five indoor cassettes independently.
• The system includes a reversing valve to switch between cooling and heating modes.
• To prevent icing during cold-weather heating, the unit can automatically trigger a brief cooling cycle to de-ice the coils.

• The capacity of this unit is actually a hair less than the total of the five ceiling cassettes that we have indoors but in practical terms that's never gonna matter.

Pressure Testing and Commissioning [00:13:30]

• A nitrogen pressure test is essential to verify that all flared connections are airtight before finalizing the install.
• Initial pressure drops indicate leaks, which must be identified using bubble solution and corrected before charging the system.
• The system features a built-in delay to protect the compressor from rapid cycling by the user.

• We're sitting tight at around 53 psi but you can actually see right now we're losing a little bit of pressure.

Final Cost and Performance [00:15:30]

• The total project cost for the condenser and five units was approximately $15,000 CAD ($11,000 USD).
• This represents a significant savings over the $25,000 to $30,000 quotes often required for full ducted retrofits.
• The system provides granular control, though it cannot heat one zone while cooling another simultaneously.

• This is a fraction of the price we actually ran into a similar situation in creator warehouse two where they wanted to duct in a bunch of AC and I was like hey can you just do a mini split.